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Biology Extended Essay Topics and RQs for IBDP

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• Writing Metier

It’s time for our exploration of Biology extended essay topics, a resource designed to spark your curiosity and guide your research interests in the vast and vibrant field of biology. 

Whether you’re fascinated by the intricate workings of ecosystems or intrigued by the complexities of cellular processes, this article offers a diverse range of topics collected by expert academic writers to suit your interests. 

NB! If you need assistance with your Biology assignments, you can use our biology essay writing service , which will surely assist you. Now, let’s get back to the main question of the article – BIO EE topic ideas.

Bio EE topic categories

List of biology extended essay topic categories I’ll cover in this article.

• Impact of Urban Development on Local Ecosystems – Investigating the effects of urban expansion on biodiversity in a specific area.
• Marine Biology and Ocean Acidification – Studying the impact of changing pH levels on marine life.
• Invasive Species and Their Impact on Biodiversity – Analyzing how a particular invasive species has affected native wildlife.
• Conservation Efforts for Endangered Species – Evaluating the effectiveness of current conservation strategies for a specific endangered species.
• Climate Change and Its Effects on Ecosystems – Researching how a particular ecosystem has been impacted by climate change.
• Nutrition and Diet’s Impact on Human Health – Exploring the effects of a specific diet on human health.
• Exercise Physiology – Investigating how different types of exercise affect a particular aspect of human health.
• Neurobiology of Sleep – Studying the effects of sleep patterns on cognitive functions.
• Genetic Factors in Diseases – Exploring the role of genetics in the susceptibility to a specific disease.
• Impact of Environmental Factors on Allergies – Analyzing how environmental changes have influenced the prevalence of allergies.
• Gene Expression in Cancer Cells – Investigating how gene expression differs in cancerous versus normal cells.
• Protein Synthesis and Its Regulation – Studying the regulation of protein synthesis in a specific organism or cell type.
• Stem Cell Research and Regenerative Medicine – Exploring the potential of stem cells in treating a specific condition.
• Viral Replication and Host Interaction – Examining how a particular virus replicates and interacts with its host.
• DNA Repair Mechanisms – Investigating the efficacy of different DNA repair mechanisms under various conditions.
• Photosynthesis Variations Among Plant Species – Comparing photosynthetic efficiency in different plant species.
• Impact of Climate Change on Plant Growth – Studying how changing climates affect the growth of a specific plant species.
• Medicinal Properties of Plants – Investigating the medicinal properties of a specific plant.
• Plant Defense Mechanisms Against Pathogens – Exploring how a particular plant species defends itself against pathogens.
• Genetic Modification and Crop Improvement – Analyzing the impacts of genetic modification on a specific crop’s traits.
• Social Behavior in Insects – Studying the social structures and behaviors of a specific insect species.
• Bird Migration Patterns – Investigating the factors influencing migration patterns of a specific bird species.
• Physiological Adaptations in Marine Mammals – Exploring adaptations that enable marine mammals to survive in their environments.
• Impact of Environmental Stressors on Animal Behavior – Analyzing how specific stressors affect the behavior of a particular animal species.
• Endocrine Regulation in Animals – Studying how the endocrine system regulates processes in a specific animal.
• Antibiotic Resistance in Bacteria – Investigating the mechanisms of antibiotic resistance in a specific bacterial strain.
• Use of Microorganisms in Bioremediation – Exploring the use of microorganisms in cleaning up environmental pollutants.
• Genetic Engineering and Its Applications – Analyzing the applications and implications of genetic engineering in a specific field.
• Role of Microbiome in Human Health – Studying how the human microbiome influences health and disease.
• Yeast Fermentation and Its Industrial Applications – Investigating the fermentation process in yeast and its uses in industry.
• Evolutionary Adaptations to Environmental Changes – Exploring how a particular species has adapted to environmental changes over time.
• Genetic Diversity and Population Health – Studying the impact of genetic diversity on the health of a specific population.
• Molecular Basis of Inheritance – Investigating the molecular mechanisms of inheritance in a specific organism.
• Speciation and Genetic Drift – Analyzing the role of genetic drift in the speciation process.
• Human Evolutionary Biology – Studying aspects of human evolution, such as the development of specific traits.

Every category and its subcategories provide a comprehensive overview, from the microscopic wonders of microbiology to the grand scale of evolutionary biology. 

With the help of our IB writers team, I have managed to collect all these ideas for you, so I hope you will be enjoying this. I aim to inspire your investigative spirit and help you select a topic that  satisfies the IB criteria  and aligns with your passion for biology. 

IB Bio extended essay topics

So, let’s begin with a list of IB Biology EE topics list.

Ecology and Environmental Science

I’m stoked to talk about Ecology and Environmental Science . It’s all about how living things interact with each other and their surroundings. Think of it like a complex dance of life, where every move affects the whole scene. 

From the hustle and bustle of city ecosystems to the quiet, yet dynamic, world of marine biology, we’ll explore how these interactions shape our planet. We’ll also explore the hot topics of invasive species and their impacts, the heroic efforts in conservation, and the big elephant in the room – climate change. 

So, let’s get ready to explore the intricate tapestry of life that makes our world fascinating!

Impact of Urban Development on Local Ecosystems

• Research Question: How does the presence of urban green spaces affect bird species diversity in [City Name]?
• Research Question: What impact do urban heat islands have on the behavior and distribution of [Specific Animal Species] in [City Name]?

Marine Biology and Ocean Acidification

• Research Question: How does ocean acidification affect coral bleaching events in the [Specific Coral Reef Location]?
• Research Question: What is the impact of increasing ocean acidification on the shell growth and survival of [Specific Shellfish Species]?

Invasive Species and Their Impact on Biodiversity

• Research Question: What has been the impact of the invasive Zebra Mussel on native species in the Great Lakes?
• Research Question: How do invasive plant species [Specify Species] affect the growth and survival of native plants in [Specific Region]?

Conservation Efforts for Endangered Species

• Research Question: How effective have conservation strategies been in increasing the population of the Giant Panda in China?
• Research Question: What are the impacts of anti-poaching measures on the survival of Rhinoceros populations in Africa?

Climate Change and Its Effects on Ecosystems

• Research Question: How is the melting of Arctic sea ice affecting the habitat and migration patterns of polar bears?
• Research Question: What are the effects of rising global temperatures on plant and animal life in the Alpine ecosystems?

Transitioning from the external world of Ecology and Environmental Science, we now turn to the internal intricacies of Human Physiology and Health. 

This shift brings us from exploring external ecosystems to understanding our body’s inner workings, a world where lifestyle choices meet biological responses.

Human Physiology and Health

Let’s chat about Human Physiology and Health, the amazing science of how our bodies work and how we keep them ticking. We’re diving headfirst into the world of nutrition and diet – what you eat isn’t just about taste, it’s about your health too! 

Then, we’ll check out how exercise, that thing we all know we should do more of, affects our bodies in awesome ways. Ever wondered about the science of sleep and how it messes with your brain when you don’t catch enough Z’s? We’ll cover that, along with the mysteries of genetics in diseases, and how our environment plays a sneaky role in triggering allergies. 

It’s going to be an eye-opening ride through the wonders of our bodies!

Nutrition and Diet’s Impact on Human Health

• Research Question: How does adherence to the Mediterranean diet affect cardiovascular health indicators in adults?
• Research Question: What is the impact of a long-term vegan diet on nutrient absorption and health in teenagers?

Exercise Physiology

• Research Question: How does HIIT affect cardiovascular fitness in young adults?
• Research Question: What are the effects of regular yoga practice on stress and anxiety levels in college students?

Neurobiology of Sleep

• Research Question: How does sleep deprivation impact cognitive performance and memory in high school students?
• Research Question: What is the relationship between sleep patterns and academic performance in IB students?

Genetic Factors in Diseases

• Research Question: How do specific genetic factors contribute to the risk of developing Alzheimer’s disease?
• Research Question: What is the contribution of genetics to the onset of Type 2 Diabetes in populations with high prevalence rates?

Impact of Environmental Factors on Allergies

• Research Question: What is the correlation between air pollution levels and the prevalence of respiratory allergies in urban children?
• Research Question: How has climate change influenced the prevalence and severity of allergic diseases in [Specific Region]?

Moving from Human Physiology and Health, we zoom into the realm of Cellular and Molecular Biology. 

Here, we swap the broader human health perspective for a closer look at life’s building blocks, delving into the microscopic universe that operates within every living being.

Cellular and Molecular Biology

Ready to geek out on Cellular and Molecular Biology? This is where we get down to the nitty-gritty of life – the cells and molecules that make up every living thing. 

We’re talking about the big bad world of cancer cells and what makes them tick, the fascinating process of how our cells make proteins, and the cutting-edge stuff like stem cell research and how viruses play a game of cat and mouse with our bodies. 

Meanwhile, make sure also to check our article with biology research paper topics for all students.

Plus, we’ll unravel the mysteries of how our cells fix their own DNA. It’s like being a detective, but for biology. Trust me, it’s cooler than it sounds!

Gene Expression in Cancer Cells

• Research Question: How does gene expression in breast cancer cells differ from that in normal breast tissue?
• Research Question: What role do specific oncogenes play in the development of colorectal cancer?

Protein Synthesis and Its Regulation

• Research Question: How is protein synthesis regulated in response to physical exercise in human muscle cells?
• Research Question: How do bacterial cells regulate protein synthesis under environmental stress conditions?

Stem Cell Research and Regenerative Medicine

• Research Question: What is the potential of stem cell therapy in the treatment of Parkinson’s Disease?
• Research Question: How can stem cells be used to repair damaged heart tissue?

Viral Replication and Host Interaction

• Research Question: How does HIV replicate within human cells, and what is its impact on the immune system?
• Research Question: How does the Influenza virus adapt to host immune responses over time?

DNA Repair Mechanisms

• Research Question: How do DNA repair mechanisms change as human cells age?
• Research Question: How effective are DNA repair mechanisms in skin cells exposed to different levels of UV radiation?

After diving into the microcosm of cells and molecules, we transition to Plant Biology. 

This shift steers us from the foundations of life at the cellular level to the diverse world of plants, exploring how these organisms harness and embody basic biological principles.

Plant Biology

Let’s dive into the world of Plant Biology! Plants are not just pretty to look at; they’re the backbone of all life on Earth. 

We’ll be talking about how they turn sunlight into food – a process that’s as important as it is fascinating. Ever wonder how plants are coping with our changing climate or what superpowers medicinal plants have? We’ve got that covered. 

We’ll also explore the secret life of plants, how they defend themselves against enemies, and the science behind making them stronger and better through genetic modification. 

It’s time to get our hands dirty and uncover the secrets of the plant world!

Photosynthesis Variations Among Plant Species

• Research Question: How does photosynthetic efficiency compare between C3 and C4 plants under varying light conditions?
• Research Question: What is the effect of varying light intensities on the rate of photosynthesis in [Specific Aquatic Plant Species]?

Impact of Climate Change on Plant Growth

• Research Question: How are Arctic tundra plants adapting their growth patterns in response to global warming?
• Research Question: What is the impact of elevated atmospheric CO2 levels on the growth of [Specific Plant Species]?

Medicinal Properties of Plants

• Research Question: What are the anti-inflammatory properties of [Specific Medicinal Plant] and how can they be harnessed?
• Research Question: What is the antioxidant capacity of different herbal teas, and how does it affect human health?

Plant Defense Mechanisms Against Pathogens

• Research Question: How do [Specific Plant Species] defend themselves against fungal infections?
• Research Question: What role do secondary metabolites play in the defense mechanisms of [Specific Plant Species] against herbivores?

Genetic Modification and Crop Improvement

• Research Question: How effective are genetically modified crops in resisting drought conditions compared to traditional varieties?
• Research Question: What is the impact of genetic modification on the nutrient content of [Specific Crop]?

From the stationary life of plants, we now step into the dynamic world of Animal Behavior and Physiology. This change of scene introduces us to the complex behaviors and physiological adaptations of animals, offering a contrasting perspective to plant biology.

Animal Behavior and Physiology

Let’s jump into the wild and wonderful world of Animal Behavior and Physiology. This is where we get to spy on the animal kingdom and learn about their secret lives. 

From the social gossip of insects to the globe-trotting adventures of migratory birds, animals have some amazing stories to tell. 

We’ll also look at how marine animals have adapted to their deep and mysterious homes, how animals respond when their environment goes bonkers, and the hormonal soap operas that dictate their lives. 

It’s like being a fly on the wall in the most interesting nature documentary ever!

Social Behavior in Insects

• Research Question: How does the social structure of honeybee colonies affect their survival and productivity?
• Research Question: What are the primary communication mechanisms used in ant colonies, and how do they impact colony efficiency?

Bird Migration Patterns

• Research Question: How has climate change affected the migration routes of [Specific Bird Species]?
• Research Question: How do magnetic fields influence the migration patterns of [Specific Bird Species]?

Physiological Adaptations in Marine Mammals

• Research Question: What physiological adaptations allow sperm whales to dive to extreme depths?
• Research Question: How do polar bears regulate their body temperature in the Arctic environment?

Impact of Environmental Stressors on Animal Behavior

• Research Question: How does underwater noise pollution affect the behavior and communication of dolphins?
• Research Question: What are the effects of urban light pollution on the nocturnal activities of [Specific Nocturnal Animal Species]?

Endocrine Regulation in Animals

• Research Question: How do hormones regulate the reproductive behaviors in [Specific Bird Species]?
• Research Question: How do stress-induced cortisol levels affect the behavior of [Specific Wild Animal Species] in their natural habitat?

Leaving the observable world of animals, we enter the less visible but equally important sphere of Microbiology and Biotechnology. This transition takes us from larger life forms to the microscopic, where tiny organisms significantly impact our health, environment, and technology.

Microbiology and Biotechnology

Alright, microbe hunters and tech wizards, it’s time to zoom in on Microbiology and Biotechnology. This is the world of the tiny, where bacteria and viruses hang out, and where science meets innovation . 

We’re going to explore the battleground of antibiotic resistance, how we can use tiny organisms to clean up our messes, and the mind-blowing possibilities of genetic engineering. 

Ever thought about how your gut buddies – the microbiome – affect your health? We’ll get into that too, along with the yeast party that’s behind some of your favorite bread and beverages.

Antibiotic Resistance in Bacteria

• Research Question: What factors have contributed to the rise of Methicillin-resistant Staphylococcus aureus (MRSA) in hospitals?
• Research Question: What are the primary mechanisms of antibiotic resistance in Escherichia coli strains found in [Specific Environment]?

Use of Microorganisms in Bioremediation

• Research Question: How effective are specific bacterial species in the bioremediation of oil spills?
• Research Question: What is the effectiveness of using fungi in the phytoremediation of soils contaminated with heavy metals?

Genetic Engineering and Its Applications

• Research Question: What is the potential of CRISPR-Cas9 technology in preventing genetic diseases?
• Research Question: How has genetic engineering been used to enhance the nutritional quality of [Specific Crop]?

Role of Microbiome in Human Health

• Research Question: What is the relationship between the gut microbiome and obesity in adults?
• Research Question: How does the diversity of the human microbiome affect immune system functioning?

Yeast Fermentation and Its Industrial Applications

• Research Question: How efficient is yeast fermentation in the production of biofuels compared to traditional methods?
• Research Question: How do different yeast strains affect the flavor profiles in beer brewing?

Finally, we shift from the practical applications in Microbiology and Biotechnology to the historical narrative of Evolution and Genetics. This move links present-day biological understanding to the historical journey of life, unraveling how genetic heritage and evolutionary processes shape all living things.

Evolution and Genetics

Ready to unravel the tales of Evolution and Genetics? This is where we figure out how life on Earth got to be as diverse and fantastic as it is. We’ll be exploring the incredible adaptations organisms have made to survive and thrive, how genetic diversity is crucial for the health of species, and the molecular secrets behind inheritance. 

Ever pondered how new species come into being or what genetics reveal about our own ancient history ? Well, you’re in for a treat. We’re about to walk through time and genes to discover the roots and branches of the tree of life. Buckle up!

Evolutionary Adaptations to Environmental Changes

• Research Question: What evolutionary adaptations have enabled cacti to thrive in harsh desert environments?
• Research Question: How have Galápagos finches undergone adaptive radiation in response to their environment?

Genetic Diversity and Population Health

• Research Question: How does genetic diversity affect the health and survival of animal populations on isolated islands?
• Research Question: How can conservation genetics be used to enhance the survival prospects of [Specific Endangered Species]?

Molecular Basis of Inheritance

• Research Question: What is the molecular basis of inheritance for Sickle Cell Anemia?
• Research Question: How can mitochondrial DNA be used to trace maternal lineage in human populations?

Speciation and Genetic Drift

• Research Question: What role has genetic drift played in the speciation of cichlids in Lake Victoria?
• Research Question: How does genetic drift affect the genetic diversity of small, isolated animal populations?

Human Evolutionary Biology

• Research Question: What evolutionary factors contributed to the development of bipedalism in early humans?
• Research Question: What are the key genetic adaptations that enable humans to live at high altitudes?

These topics and questions aim to inspire in-depth exploration and research, allowing students to delve into various aspects of biology, from molecular to ecosystem levels. 

Use them as an inspiration for your future Ib extended essay.

Select your topic wisely!

The world of biology is rich with diverse topics suitable for an Extended Essay. From the tiny intricacies of cellular biology to the broad complexities of environmental science, each area offers a unique perspective and a chance for in-depth exploration . 

The key to a successful essay is choosing a topic that not only interests you but also challenges your analytical and research skills.

Need Extra Support?

If you’re seeking guidance with your topic selection, or if you need assistance in writing or editing your Biology Extended Essay , our team at Writing Metier is here to help. 

Our experienced IB writers are equipped to provide the support you need to refine your ideas and enhance your writing. Contact us for personalized assistance, or simply fill out our online order form with details of your IB EE and ensure your essay is a reflection of your best efforts.

Free topic suggestions

Vasy kafidoff.

Vasyl Kafidoff is a co-founder and CEO at WritingMetier. He is interested in education and how modern technology makes it more accessible. He wants to bring awareness about new learning possibilities as an educational specialist. When Vasy is not working, he’s found behind a drum kit.

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Sat / act prep online guides and tips, the complete ib extended essay guide: examples, topics, and ideas.

International Baccalaureate (IB)

IB students around the globe fear writing the Extended Essay, but it doesn't have to be a source of stress! In this article, I'll get you excited about writing your Extended Essay and provide you with the resources you need to get an A on it.

If you're reading this article, I'm going to assume you're an IB student getting ready to write your Extended Essay. If you're looking at this as a potential future IB student, I recommend reading our introductory IB articles first, including our guide to what the IB program is and our full coverage of the IB curriculum .

IB Extended Essay: Why Should You Trust My Advice?

I myself am a recipient of an IB Diploma, and I happened to receive an A on my IB Extended Essay. Don't believe me? The proof is in the IBO pudding:

If you're confused by what this report means, EE is short for Extended Essay , and English A1 is the subject that my Extended Essay topic coordinated with. In layman's terms, my IB Diploma was graded in May 2010, I wrote my Extended Essay in the English A1 category, and I received an A grade on it.

What Is the Extended Essay in the IB Diploma Programme?

The IB Extended Essay, or EE , is a mini-thesis you write under the supervision of an IB advisor (an IB teacher at your school), which counts toward your IB Diploma (learn more about the major IB Diploma requirements in our guide) . I will explain exactly how the EE affects your Diploma later in this article.

For the Extended Essay, you will choose a research question as a topic, conduct the research independently, then write an essay on your findings . The essay itself is a long one—although there's a cap of 4,000 words, most successful essays get very close to this limit.

Keep in mind that the IB requires this essay to be a "formal piece of academic writing," meaning you'll have to do outside research and cite additional sources.

The IB Extended Essay must include the following:

• A title page
• Contents page
• Introduction
• Body of the essay
• References and bibliography

Additionally, your research topic must fall into one of the six approved DP categories , or IB subject groups, which are as follows:

• Group 1: Studies in Language and Literature
• Group 2: Language Acquisition
• Group 3: Individuals and Societies
• Group 4: Sciences
• Group 5: Mathematics
• Group 6: The Arts

Once you figure out your category and have identified a potential research topic, it's time to pick your advisor, who is normally an IB teacher at your school (though you can also find one online ). This person will help direct your research, and they'll conduct the reflection sessions you'll have to do as part of your Extended Essay.

As of 2018, the IB requires a "reflection process" as part of your EE supervision process. To fulfill this requirement, you have to meet at least three times with your supervisor in what the IB calls "reflection sessions." These meetings are not only mandatory but are also part of the formal assessment of the EE and your research methods.

According to the IB, the purpose of these meetings is to "provide an opportunity for students to reflect on their engagement with the research process." Basically, these meetings give your supervisor the opportunity to offer feedback, push you to think differently, and encourage you to evaluate your research process.

The final reflection session is called the viva voce, and it's a short 10- to 15-minute interview between you and your advisor. This happens at the very end of the EE process, and it's designed to help your advisor write their report, which factors into your EE grade.

Here are the topics covered in your viva voce :

• A check on plagiarism and malpractice
• Your reflection on your project's successes and difficulties
• Your reflection on what you've learned during the EE process

Your completed Extended Essay, along with your supervisor's report, will then be sent to the IB to be graded. We'll cover the assessment criteria in just a moment.

We'll help you learn how to have those "lightbulb" moments...even on test day!  

What Should You Write About in Your IB Extended Essay?

You can technically write about anything, so long as it falls within one of the approved categories listed above.

It's best to choose a topic that matches one of the IB courses , (such as Theatre, Film, Spanish, French, Math, Biology, etc.), which shouldn't be difficult because there are so many class subjects.

Here is a range of sample topics with the attached extended essay:

• Biology: The Effect of Age and Gender on the Photoreceptor Cells in the Human Retina
• Chemistry: How Does Reflux Time Affect the Yield and Purity of Ethyl Aminobenzoate (Benzocaine), and How Effective is Recrystallisation as a Purification Technique for This Compound?
• English: An Exploration of Jane Austen's Use of the Outdoors in Emma
• Geography: The Effect of Location on the Educational Attainment of Indigenous Secondary Students in Queensland, Australia
• Math: Alhazen's Billiard Problem
• Visual Arts: Can Luc Tuymans Be Classified as a Political Painter?

You can see from how varied the topics are that you have a lot of freedom when it comes to picking a topic . So how do you pick when the options are limitless?

How to Write a Stellar IB Extended Essay: 6 Essential Tips

Below are six key tips to keep in mind as you work on your Extended Essay for the IB DP. Follow these and you're sure to get an A!

#1: Write About Something You Enjoy

You can't expect to write a compelling essay if you're not a fan of the topic on which you're writing. For example, I just love British theatre and ended up writing my Extended Essay on a revolution in post-WWII British theatre. (Yes, I'm definitely a #TheatreNerd.)

I really encourage anyone who pursues an IB Diploma to take the Extended Essay seriously. I was fortunate enough to receive a full-tuition merit scholarship to USC's School of Dramatic Arts program. In my interview for the scholarship, I spoke passionately about my Extended Essay; thus, I genuinely think my Extended Essay helped me get my scholarship.

But how do you find a topic you're passionate about? Start by thinking about which classes you enjoy the most and why . Do you like math classes because you like to solve problems? Or do you enjoy English because you like to analyze literary texts?

Keep in mind that there's no right or wrong answer when it comes to choosing your Extended Essay topic. You're not more likely to get high marks because you're writing about science, just like you're not doomed to failure because you've chosen to tackle the social sciences. The quality of what you produce—not the field you choose to research within—will determine your grade.

Once you've figured out your category, you should brainstorm more specific topics by putting pen to paper . What was your favorite chapter you learned in that class? Was it astrophysics or mechanics? What did you like about that specific chapter? Is there something you want to learn more about? I recommend spending a few hours on this type of brainstorming.

One last note: if you're truly stumped on what to research, pick a topic that will help you in your future major or career . That way you can use your Extended Essay as a talking point in your college essays (and it will prepare you for your studies to come too!).

#2: Select a Topic That Is Neither Too Broad nor Too Narrow

There's a fine line between broad and narrow. You need to write about something specific, but not so specific that you can't write 4,000 words on it.

You can't write about WWII because that would be a book's worth of material. You also don't want to write about what type of soup prisoners of war received behind enemy lines, because you probably won’t be able to come up with 4,000 words of material about it. However, you could possibly write about how the conditions in German POW camps—and the rations provided—were directly affected by the Nazis' successes and failures on the front, including the use of captured factories and prison labor in Eastern Europe to increase production. WWII military history might be a little overdone, but you get my point.

If you're really stuck trying to pinpoint a not-too-broad-or-too-narrow topic, I suggest trying to brainstorm a topic that uses a comparison. Once you begin looking through the list of sample essays below, you'll notice that many use comparisons to formulate their main arguments.

I also used a comparison in my EE, contrasting Harold Pinter's Party Time with John Osborne's Look Back in Anger in order to show a transition in British theatre. Topics with comparisons of two to three plays, books, and so on tend to be the sweet spot. You can analyze each item and then compare them with one another after doing some in-depth analysis of each individually. The ways these items compare and contrast will end up forming the thesis of your essay!

When choosing a comparative topic, the key is that the comparison should be significant. I compared two plays to illustrate the transition in British theatre, but you could compare the ways different regional dialects affect people's job prospects or how different temperatures may or may not affect the mating patterns of lightning bugs. The point here is that comparisons not only help you limit your topic, but they also help you build your argument.

Comparisons are not the only way to get a grade-A EE, though. If after brainstorming, you pick a non-comparison-based topic and are still unsure whether your topic is too broad or narrow, spend about 30 minutes doing some basic research and see how much material is out there.

If there are more than 1,000 books, articles, or documentaries out there on that exact topic, it may be too broad. But if there are only two books that have any connection to your topic, it may be too narrow. If you're still unsure, ask your advisor—it's what they're there for! Speaking of advisors...

Don't get stuck with a narrow topic!

#3: Choose an Advisor Who Is Familiar With Your Topic

If you're not certain of who you would like to be your advisor, create a list of your top three choices. Next, write down the pros and cons of each possibility (I know this sounds tedious, but it really helps!).

For example, Mr. Green is my favorite teacher and we get along really well, but he teaches English. For my EE, I want to conduct an experiment that compares the efficiency of American electric cars with foreign electric cars.

I had Ms. White a year ago. She teaches physics and enjoyed having me in her class. Unlike Mr. Green, Ms. White could help me design my experiment.

Based on my topic and what I need from my advisor, Ms. White would be a better fit for me than would Mr. Green (even though I like him a lot).

The moral of my story is this: do not just ask your favorite teacher to be your advisor . They might be a hindrance to you if they teach another subject. For example, I would not recommend asking your biology teacher to guide you in writing an English literature-based EE.

There can, of course, be exceptions to this rule. If you have a teacher who's passionate and knowledgeable about your topic (as my English teacher was about my theatre topic), you could ask that instructor. Consider all your options before you do this. There was no theatre teacher at my high school, so I couldn't find a theatre-specific advisor, but I chose the next best thing.

Before you approach a teacher to serve as your advisor, check with your high school to see what requirements they have for this process. Some IB high schools require your IB Extended Essay advisor to sign an Agreement Form , for instance.

Make sure that you ask your IB coordinator whether there is any required paperwork to fill out. If your school needs a specific form signed, bring it with you when you ask your teacher to be your EE advisor.

#4: Pick an Advisor Who Will Push You to Be Your Best

Some teachers might just take on students because they have to and aren't very passionate about reading drafts, only giving you minimal feedback. Choose a teacher who will take the time to read several drafts of your essay and give you extensive notes. I would not have gotten my A without being pushed to make my Extended Essay draft better.

Ask a teacher that you have experience with through class or an extracurricular activity. Do not ask a teacher that you have absolutely no connection to. If a teacher already knows you, that means they already know your strengths and weaknesses, so they know what to look for, where you need to improve, and how to encourage your best work.

Also, don't forget that your supervisor's assessment is part of your overall EE score . If you're meeting with someone who pushes you to do better—and you actually take their advice—they'll have more impressive things to say about you than a supervisor who doesn't know you well and isn't heavily involved in your research process.

Be aware that the IB only allows advisors to make suggestions and give constructive criticism. Your teacher cannot actually help you write your EE. The IB recommends that the supervisor spends approximately two to three hours in total with the candidate discussing the EE.

#5: Make Sure Your Essay Has a Clear Structure and Flow

The IB likes structure. Your EE needs a clear introduction (which should be one to two double-spaced pages), research question/focus (i.e., what you're investigating), a body, and a conclusion (about one double-spaced page). An essay with unclear organization will be graded poorly.

The body of your EE should make up the bulk of the essay. It should be about eight to 18 pages long (again, depending on your topic). Your body can be split into multiple parts. For example, if you were doing a comparison, you might have one third of your body as Novel A Analysis, another third as Novel B Analysis, and the final third as your comparison of Novels A and B.

If you're conducting an experiment or analyzing data, such as in this EE , your EE body should have a clear structure that aligns with the scientific method ; you should state the research question, discuss your method, present the data, analyze the data, explain any uncertainties, and draw a conclusion and/or evaluate the success of the experiment.

#6: Start Writing Sooner Rather Than Later!

You will not be able to crank out a 4,000-word essay in just a week and get an A on it. You'll be reading many, many articles (and, depending on your topic, possibly books and plays as well!). As such, it's imperative that you start your research as soon as possible.

Each school has a slightly different deadline for the Extended Essay. Some schools want them as soon as November of your senior year; others will take them as late as February. Your school will tell you what your deadline is. If they haven't mentioned it by February of your junior year, ask your IB coordinator about it.

Some high schools will provide you with a timeline of when you need to come up with a topic, when you need to meet with your advisor, and when certain drafts are due. Not all schools do this. Ask your IB coordinator if you are unsure whether you are on a specific timeline.

Below is my recommended EE timeline. While it's earlier than most schools, it'll save you a ton of heartache (trust me, I remember how hard this process was!):

• January/February of Junior Year: Come up with your final research topic (or at least your top three options).
• February of Junior Year: Approach a teacher about being your EE advisor. If they decline, keep asking others until you find one. See my notes above on how to pick an EE advisor.
• April/May of Junior Year: Submit an outline of your EE and a bibliography of potential research sources (I recommend at least seven to 10) to your EE advisor. Meet with your EE advisor to discuss your outline.
• Summer Between Junior and Senior Year: Complete your first full draft over the summer between your junior and senior year. I know, I know—no one wants to work during the summer, but trust me—this will save you so much stress come fall when you are busy with college applications and other internal assessments for your IB classes. You will want to have this first full draft done because you will want to complete a couple of draft cycles as you likely won't be able to get everything you want to say into 4,000 articulate words on the first attempt. Try to get this first draft into the best possible shape so you don't have to work on too many revisions during the school year on top of your homework, college applications, and extracurriculars.
• August/September of Senior Year: Turn in your first draft of your EE to your advisor and receive feedback. Work on incorporating their feedback into your essay. If they have a lot of suggestions for improvement, ask if they will read one more draft before the final draft.
• September/October of Senior Year: Submit the second draft of your EE to your advisor (if necessary) and look at their feedback. Work on creating the best possible final draft.
• November-February of Senior Year: Schedule your viva voce. Submit two copies of your final draft to your school to be sent off to the IB. You likely will not get your grade until after you graduate.

Remember that in the middle of these milestones, you'll need to schedule two other reflection sessions with your advisor . (Your teachers will actually take notes on these sessions on a form like this one , which then gets submitted to the IB.)

I recommend doing them when you get feedback on your drafts, but these meetings will ultimately be up to your supervisor. Just don't forget to do them!

The early bird DOES get the worm!

How Is the IB Extended Essay Graded?

Extended Essays are graded by examiners appointed by the IB on a scale of 0 to 34 . You'll be graded on five criteria, each with its own set of points. You can learn more about how EE scoring works by reading the IB guide to extended essays .

• Criterion A: Focus and Method (6 points maximum)
• Criterion B: Knowledge and Understanding (6 points maximum)
• Criterion C: Critical Thinking (12 points maximum)
• Criterion D: Presentation (4 points maximum)
• Criterion E: Engagement (6 points maximum)

How well you do on each of these criteria will determine the final letter grade you get for your EE. You must earn at least a D to be eligible to receive your IB Diploma.

Although each criterion has a point value, the IB explicitly states that graders are not converting point totals into grades; instead, they're using qualitative grade descriptors to determine the final grade of your Extended Essay . Grade descriptors are on pages 102-103 of this document .

Here's a rough estimate of how these different point values translate to letter grades based on previous scoring methods for the EE. This is just an estimate —you should read and understand the grade descriptors so you know exactly what the scorers are looking for.

Here is the breakdown of EE scores (from the May 2021 bulletin):

How Does the Extended Essay Grade Affect Your IB Diploma?

The Extended Essay grade is combined with your TOK (Theory of Knowledge) grade to determine how many points you get toward your IB Diploma.

To learn about Theory of Knowledge or how many points you need to receive an IB Diploma, read our complete guide to the IB program and our guide to the IB Diploma requirements .

This diagram shows how the two scores are combined to determine how many points you receive for your IB diploma (3 being the most, 0 being the least). In order to get your IB Diploma, you have to earn 24 points across both categories (the TOK and EE). The highest score anyone can earn is 45 points.

Let's say you get an A on your EE and a B on TOK. You will get 3 points toward your Diploma. As of 2014, a student who scores an E on either the extended essay or TOK essay will not be eligible to receive an IB Diploma .

Prior to the class of 2010, a Diploma candidate could receive a failing grade in either the Extended Essay or Theory of Knowledge and still be awarded a Diploma, but this is no longer true.

Figuring out how you're assessed can be a little tricky. Luckily, the IB breaks everything down here in this document . (The assessment information begins on page 219.)

40+ Sample Extended Essays for the IB Diploma Programme

In case you want a little more guidance on how to get an A on your EE, here are over 40 excellent (grade A) sample extended essays for your reading pleasure. Essays are grouped by IB subject.

• Business Management 1
• Chemistry 1
• Chemistry 2
• Chemistry 3
• Chemistry 4
• Chemistry 5
• Chemistry 6
• Chemistry 7
• Computer Science 1
• Economics 1
• Design Technology 1
• Design Technology 2
• Environmental Systems and Societies 1
• Geography 1
• Geography 2
• Geography 3
• Geography 4
• Geography 5
• Geography 6
• Literature and Performance 1
• Mathematics 1
• Mathematics 2
• Mathematics 3
• Mathematics 4
• Mathematics 5
• Philosophy 1
• Philosophy 2
• Philosophy 3
• Philosophy 4
• Philosophy 5
• Psychology 1
• Psychology 2
• Psychology 3
• Psychology 4
• Psychology 5
• Social and Cultural Anthropology 1
• Social and Cultural Anthropology 2
• Social and Cultural Anthropology 3
• Sports, Exercise and Health Science 1
• Sports, Exercise and Health Science 2
• Visual Arts 1
• Visual Arts 2
• Visual Arts 3
• Visual Arts 4
• Visual Arts 5
• World Religion 1
• World Religion 2
• World Religion 3

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human physiology Notes

Human physiology, approaching the topic:.

Human nutrition

Essential and non-essential nutrients.

• Essential amino acids
• Essential fatty acids
• If the necessary nutrients are synthesised in our bodies by metabolism, then they are called non-essential nutrients and if some nutrients are not getting synthesised in the body but need to be taken as a part of our diet, those are called essential nutrients .

Amino acids

• Out of 20 amino acids, 9 are essential amino acids which are supplied in our regular diet.
• These 9 essential amino acids are; Valine, phenylalanine, histidine, leucine, isoleucine, tryptophan, threonine, lysine and methionine.
• Deficiency of one or more of the essential amino acids in diet may not lead to necessary protein formation and thus may affect the individuals.
• These are the inorganic substances which are mostly taken in the ionic form (i.e. as electrolytes) and are needed in very small quantities.
• Some of the most important minerals are Ca 2+ , Fe 2+ ,Na + , Mg + and Cl – ions. Calcium is needed for bones, iron is embedded in haemoglobin molecule, sodium is used in generating action potentials, magnesium is used in muscle functioning and chloride maintains the electrolytic balance in the blood.
• Electrolytic imbalance causes muscle cramps.
• These are organic molecules, which are taken as part of diet but many of them are also synthesised in our body.
• These are also needed in small quantities and plant food is the main source.
• Deficiency of vitamin C (an essential vitamin), also called an ascorbic acid, in the body may cause scurvy .
• Deficiency of vitamin D may cause rickets . In rickets, deformities of bones occur because vitamin D is necessary for better formation of the bones. Leg bones are affected mostly.
• Children are at most risk to be affected by this disease but similar conditions can occur in adults as well, called osteomalacia.

Fatty acids

• Omega-3 and omega-6 are the two essential fatty acids that are need to be taken in our diet. Fat is the only source for these two fatty acids to be taken in.
• Fatty acids are marked by their long hydrocarbon chain and a carboxyl group at one end.
• Cholesterols are therefore come out to be beneficial and harmful as well. They are harmful in the way that, plaque formation occurs inside the arteries making them even smaller in diameters, called atherosclerosis . The blockage in the arteries may result in the heart attack.

Malnutrition

• Malnutrition is the result of intake of unbalanced or improper diet. The diet can be unbalanced or fail to provide essential nutrients leading to starvation , or it may have excess amounts of carbohydrates and fats leading to overweight .
• Hypertension: More the weight, more the blood would be needed to supply oxygen to every cell in the body. Increase in the volume of blood will increase the blood pressure in the walls of the arteries and therefore causes hypertension.
• Type II diabetes: With overweight, more and more lipids and carbohydrates are getting inside the body which enhances the glucose levels inside the blood. The insulin production gets low, and so the benefit of insulin to remove glucose from the blood also gets reduced.
• If not enough carbohydrates or fats are provided to the individual, then the stored glycogen (in the liver) will be used as a source of glucose. After that, the body fat will be used and if it gets even worse, then proteins will be used as a source of energy.
• Body tissues can also be used at last, starting from the skeletal muscle.

Digestive process

• Secretions through exocrine glands are necessary for digestion. Exocrine secretions occur through ducts and on the specific location it is meant to be functional on.

Gastric secretions

• There are three glandular secretions; HCl, pepsin and mucus which are produced by three glandular cells present in the gastric pits .
• Any sense of food triggers nervous responses in the body. ANS sends impulses to the medulla oblongata which responds by sending action potentials by vagus nerve , directly to the stomach causing it to release HCl, pepsinogen and mucus in the stomach.
• Gastrin (a hormone secreted by endocrine gland) is also released due to this response which results in even more secretion of HCl and pepsinogen.
• When the chyme travels into the duodenum from the stomach, secretin hormone is released which inhibits gastric pit activity.
• HCl helps in denaturing the proteins and killing harmful pathogens, pepsin catalyses the hydrolysis of large polypeptide chains into smaller units.

Stomach ulcers!

• The pH of the fluid in the stomach can be as low as 2, this may cause partial digestion of the lining of the stomach and stomach ulcers. The bacteria called Helicobacter pylori , has a major contributing role in causing ulcers.

Adaptive Absorption

• Absorption of the digested food occurs in small intestine lined by
• Villi further contain projections called microvilli for even better
• Through the plasma membrane using active transport mechanism . ATP for active transport is provided by mitochondria present in the

• Basal labyrinth also increases the surface area for efficient transport
• Tight junctions between each epithelial cell ensure that, no molecule can pass through without entering the epithelial

Functions of the Liver

Circulation of blood considering liver

• Two major blood vessels; hepatic portal vein and hepatic artery , flow blood in the liver which exits by only one (hepatic vein) .
• The capillaries of the liver which receives blood from the two blood vessels are called sinusoids .

• Specialised leucocyte cells called Kupffer cells are present inside the sinusoids which help in recycling of older erythrocytes by breaking down its haemoglobin.

Functions of liver

• The food we eat may contain a number of toxins like the crop is sprayed with pesticides, herbicides etc., added preservatives, flavouring substances etc. Liver comes in action to remove these substances.
• Kupffer cells phagocytose many bacteria in the blood and also contain many lysozymes. Removes toxins from the blood
• Hepatocytes extract toxin from blood plasma, modifies them to weaker molecules and make them water soluble so that they can be eliminated by kidney.
• Every time blood passes through liver sinusoids, the exchange of nutrients will occur to maintain the homeostasis of the body.
• Hepatocytes will absorb much of glucose if blood glucose levels are high and if blood glucose levels are low, then the stored glycogen will be converted into glucose and added into the bloodstream.
• This is of course hormonal, taking into account the insulin and glucagon secretion from pancreas.
• The erythrocytes need to be replaced every 120 days because they die after 4
• Soon after they die, the haemoglobin molecules are released from these cells due to weakening of the cell membranes, in the blood stream. These are phagocytosed by Kupffer cells in sinusoids and dissembled into its

Constituents of haemoglobin!

Four globins (polypeptides), four haem groups (one in each globin) and four iron atoms (one in each haem group).

• Globin proteins are hydrolysed into amino acids which draw into bloodstream.
• Iron atom is removed, some of it is stored in the liver and rest is sent to bone marrow for production of new erythrocytes.
• The remaining part after iron removal is called bilirubin which is absorbed by hepatocytes and becomes one of the components of bile.
• Lipid molecules in the food are hard to digest because they clump together, making it difficult for lipase to act upon them.
• Bile juice from the liver breaks up the clump and allows lipase to breakdown lipid molecules.
• Hepatocytes produce plasma proteins which add up in the plasma of the blood.

Structure of heart

• Heart is made up of cardiac muscle which has sarcomeres like in skeletal muscle.
• The muscle cells are joined to each other by intercalated discs which helps them to work together as a unit. Also they have disc-shaped openings called gap junctions through which the cytoplasm of the cells can pass. This allows an electrical signal to pass quickly from one cell to another.
• Cardiac muscle tissues have large mitochondria and are highly vascular so as to prevent them from getting fatigue.

Heart valves:

• Two atrioventricular valves on left and right side of the heart, separating left atrium from left ventricle and right atrium from right ventricle. These two valves are called bicuspid or mitral valve and tricuspid valve respectively on the left and right side.
• Left and right semilunar valves are also present on the left and right side of the heart. Left semilunar valve, also called aortic valve separates left ventricle and its outlet of Right semilunar valve, also called pulmonary valve separates right ventricle and its outlet of blood.
• The sounds of the heart i.e. lub and dub comes from the closure of these valves timely.

Heart rate mechanism

• Heart is wholly made up of muscles known as cardiac muscles . These muscles contract and relax spontaneously and this phenomenon is called myogenic muscle contraction . It is not controlled by the nervous system.
• A specialised tissue called sinoatrial node (SA node) is present in the right atrium, it is also known as pacemaker . SA nodes have the properties of both muscles and nervous system.
• SA node sends the signal after every 0.8 seconds to initiate the contraction of both the atria and the same signal is received by AV node (atrioventricular node) which further after the delay of 0.1 seconds, sends the signal for the contraction of both the ventricles. These two electrical signals maintain the synchrony between the atria and ventricular contraction.

Electrocardiogram (ECG)

Heart and problems and their treatments

Cardiac arrest and arrhythmia.

• When the heart stops working ( cardiac arrest ) or is no longer in sequence with the set of electrical impulses of a cardiac cycle ( arrhythmia ), defibrillators could be used.
• This is the device that delivers an electric shock to the heart and resets the electrical signal starting with the SA node. The resetting may cause the heart to continue with the beating.
• A condition in which a clot is formed within a blood vessel causing blockage. It is more harmful when it travels to the smaller veins, specifically called deep vein thrombosis (DVT) .
• It can be treated by using anticoagulants medicines.
• Coronary thrombosis: It is the clot that occurs in the coronary arteries of the heart (plaque formation), narrows the lumen and may eventually cause myocardial infarction .

Hypertension

• Plaque formation is one of the main reasons causing hypertension, another is loss of elasticity in arteries.
• There are two values of blood pressure; systolic pressure (when arteries are contracting) and diastolic pressure (when arteries are resting).

Hormones and metabolism

• In this system of hormone secretion, the hormones are secreted directly into the bloodstream which is accepted by the receptor molecules of the target cells.
• Pituitary gland (anterior and posterior lobe)
• Thyroid gland
• Parathyroid glands
• Adrenal glands (occurs in pair)
• Pancreas (it has both endocrine and exocrine functions)
• Ovaries (in females)

There are two types of hormones:

• Synthesised from cholesterol and therefore have the properties of lipid.
• They can easily pass through the cell membrane (lipid bilayer) due to its hydrophobic nature.
• The mechanism of action of steroid hormones; The receptor protein for hormones is present inside the cytoplasm. The steroidal hormones pass the membrane and attach to the receptor molecule, forming receptor-hormone complexes. The complex then enters the nucleus and binds to a specific gene. This way they control the protein production of the target cells.
• These are composed of amino acids and therefore have the properties of proteins. They can’t directly enter the cell membrane.
• The receptor proteins of this kind of hormones are present outside the cell membrane on which the hormones bind together.

The pituitary gland (master gland)

• It is called master gland because it secretes most of the hormones to stimulate a certain function in the body.
• It is divided into two lobes; posterior and anterior lobe. These lobes act as two different glands and therefore they are called posterior pituitary and anterior pituitary .
• It works under the orders of hypothalamus. Hormones are produced in the hypothalamus and travelled down to the pituitary to be secreted.
• Hormone secretions from posterior and anterior lobes of the pituitary work differently.
• The hormones are produced by neurosecretory cells , which are present in a unique way. The dendrites and cell body is covered under the hypothalamus and the axon part comes under the posterior lobe.
• The cell body secretes hormones and moves down to the posterior pituitary where they mix with the capillary bed.
• The hormones produced are oxytocin and ADH.
• The hormones are produced by neurosecretory cells in the hypothalamus only. They then get into the capillary bed, which collects into the portal vein .
• The portal vein travels down into the pituitary where it branches into a second capillary bed that allows it to release into the bloodstream.
• The hormones produced are thyroid stimulating hormone (TSH), FSH, LH, growth hormones (GH) and prolactin.
• Secretion of prolactin during pregnancy develops the breast to produce milk. The high oestrogen level during pregnancy inhibits milk release.
• After the birth of the child, the decline in the oestrogen production and high levels of oxytocin (due to uterine contraction) stimulates the milk secretion.

Transport of respiratory gases

Haemoglobin (hb 4 ).

• Each haemoglobin molecule inside each erythrocyte cell can occupy four oxygen molecules at most and one CO 2 molecule .
• The iron atom in the haem group bonds with oxygen i.e. four iron atoms will bond to four oxygen molecules.
• Haemoglobin changes its shape in addition to the oxygen molecule (depends on how many oxygen molecules it occupies). This is known as haemoglobin’s affinity for oxygen .
• Haemoglobin that already carries three oxygen molecules has the greater affinity for oxygen because every oxygen molecule when bonds with haemoglobin changes its shape to increase its affinity.

Oxygen dissociation curves

Carbon dioxide transport in the blood

• It is dissolved in blood plasma in some amount, some is carried by haemoglobin (causing Bohr shift) and most of it is converted into bicarbonate ions .
• Bicarbonate ions exit the erythrocyte cells by facilitated diffusion. One HCO 3 – gets out and one Cl – gets inside, as an exchange. This is called chloride shift .
• The release of H + ions decreases the pH of the blood.

Regulation of ventilation rate

• Ventilation rate is controlled by the respiratory centre in medulla oblongata.
• The rate increases when there is more CO 2 detected in blood and vice versa.
• Chemosensors are present in the inner walls of aorta and carotid arteries, which detect the CO 2 levels in the blood and generate an action potential to the respiratory centre in medulla oblongata.
• These chemoreceptors are also present in the medulla oblongata itself. When the blood passes from the capillary bed in the medulla oblongata, it detects the pH decrease or high levels of CO 2 in blood.

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Biology Extended Essay: The Complete Guide for IB Students

by  Antony W

March 13, 2023

Biology Extended Essay is an assignment that requires you to explore biological issue relevant to you and your environment.

Your focus should be on a particular biological emphasis within a broader context of scientific investigation. Given that the focus is on a biological system, you’ll have to make an analytical argument as you write the essay.

In this guide, you’ll learn exactly what you need to know about the IB Biology Extended Essay . Our goal with this lesson is to give you the most important information about the subject so that you can get the assignment done right.

What is Biology in an IB Extended Essay?

Biology in IB Extended Essay is the examination of living organisms and their life processes. The assignment integrates biological theories and examines the nature of the subject.

While you can approach a Biology EE from varying viewpoints, the treatment of the material used in your investigation must be 100% biological.

IB Biology Extended Essay Topics

The topic you choose to explore in your IB Biology Extended Essay shouldn’t be too broad or too narrow. Make sure you choose a focused topic that’s easy to investigate and easy to explain.

Your teacher expects you to explain how you arrived at your research question, and the best way to do that is to outline the aspects you wish to consider in the essay.

You may also have to formulate one or more hypothesis based on the research question.

The EE guide on the subject recommends that you choose your topics carefully, making sure you refrain from inappropriate topics such as those that are likely to inflict pain, involve the use of dangerous substances, or linked to safety concern.

You should avoid topics whose outcome are either obvious or already well known and documented in textbooks.

Doing Research for Your IB Biology Extended Essay

You will need to do primary and secondary research for your Biology Extended Essay.

1. Primary Research

For primary research, you can collect data from fieldwork, surveys, biological drawings, and biological observations.

If you’ve picked topic that requires practical work, you may have to conduct multiple, extensive fieldwork or do lab tests. In such a case, you will have to provide a detailed explanation of the experimental research procedures sued.

2. Secondary Research

When it comes to secondary research, you get data or information from literature.

Some students restate the information they collect from secondary sources, but doing so often adds little or no value to a Biology Extended Essay.

Therefore, the right approach is to analyze the data or information in an original way to add a new dimension and value to your research and to the essay at large.

Whether you do primary research, secondary research, or a combination of both, you need to make sure you have access to enough data or information to answer your research question.

How Do You Write an IB Biology Extended Essay?

The first step to writing a comprehensive, 4,000-word essay in Biology EE is to use the right scientific techniques to analyze the data you collect during research.

You then have to present your argument or evaluation based on the analysis you’ve completed.

You can include graphs, tables, and diagrams, and make sure you point out their significance in the essay so they’re easy to understand.

As with any other EE, your Biology essay should have a good structure and demonstrate a logical progression. Feel free to use headings and subheadings in the essay because it imposes a concise structure.

Your evaluation of the research questions should demonstrate that you not only understand the results from your experiments but also can explain their significance in a wider academic context.

Since you aren’t sure about what to expect from biological experiments, you may have to account for anomalies or unexpected results in your investigation.

In such a case, you have to provide explanations for the expected outcome and give an alternative explanation for such findings.

The subject also allows you to propose slight or major changes to the hypothesis presented in the essay, in which case you will have to suggest relevant approaches to testing the new changes.

Evaluation of Your Biology EE

Writing your EE in Biology also requires that you undertake a critical evaluation of the work that you have already done.

The evaluation helps you to identify and explain the limitation of your research by a number of factors including the reliability and validity of statistics, the precision of experimenting equipment and the reliability of sources.

You also need to consider biological limitations of your research. Such limitations are likely to arise from the inability to generalize based on a single form of an organism or problems of control and repeatability when using living organisms in your research.

Biology Internal Assessment vs Biology Extended Essay

It’s important to keep in mind that a Biology Extended Essay is not an extension of the Internal Assessment in the same subject. There are a few differences that set the two assignments apart, and it’s important to know them before you start working on the essay.

Get Extended Essay Writing Help

Do you need help with your Extended Essay in Biology? Our team of IB experts is here to help you write the 4,000-word essay, even if it’s on a complex topic. You can click here to learn more.

About the author 

Antony W is a professional writer and coach at Help for Assessment. He spends countless hours every day researching and writing great content filled with expert advice on how to write engaging essays, research papers, and assignments.

IB Biology EE examples

Filter exemplars, how do different concentrations of punica granatum extracts: peel, flower and leaves (10, 20, 30, 40 and 50 mg/ml) affect the rate of reaction of α-amylase and compare with metformin (anti-diabetic drug) as measured by a spectrophotometer at 587nm, to what extent do extracts of allium sativum (garlic) and zingiber officinale (ginger) reduce antimicrobial activity and how effective it is compared to antibiotics, want to get full marks for your ee allow us to review it for you 🎯, to what extent does performing the dance styles, cha cha, viennese waltz, and modern contemporary affect human fitness levels as measured by oxygen consumption (vo2) and maximum heart rate (bpm), how effective is the cone repair technique when treating ebstein’s anomaly in comparison to other treatments, how does juice from garlic allium sativum cloves prepared in different ways (fresh raw, crushed one day prior, cooked, kept in oil, fermented in brine and fermented (black garlic)) affect the growth of a non-pathogenic strain of escherichia coli, fast track your coursework with mark schemes moderated by ib examiners. upgrade now 🚀, to what extent does the presence of acetaminophen (tylenol), polymixin b (polysporin), and diphenhydramine hydrochloride (benadryl) in the growth medium of cotoneaster acutifolius affect the average change in leaf length over a period of 15 days in five different concentrations, to what extent do different concentrations of magnesium nitrate (10, 20, 30, 40, 50 mm) affect the concentration of chlorophyll a and b in ocimum basilicum at 645 nm and 662 nm wavelength using spectrophotometer, what is the effect of salinity stress (0, 50, 100, 150, 200 mm nacl) measured through microscopic (stomatal aperture) and morphological (leaf area, leaf dry mass, and root length) characteristics on pre-treated radish (raphanus sativus) seeds with magnetopriming (48 hours), how is the number of errors made by participants when attempting to distinguish between the temperature of two different water baths influenced by the hours slept within a 24-hour period, to what extent do different species of chili pepper consumption biologically affect the rate of lipid digestion in terms of ph change within 30 minutes, to what extent do phytochemicals such as resveratrol, glyceollin and epigallocatechin-3-gallate (egcg) possess comparable antibacterial effects against staphylococcus aureus bacteria to a non-prescription otitis externa (oe) treatments such as ciprofloxacin using bacillus subtilis as a prokaryotic model organism, to what extent is blood pressure related to the development of alzheimer’s disease in people in age above 50, to what extent do bioinformatic tools such as cb dock 2 and chimera help in the analysis of phytochemicals (calotropone, quercetin, thymoquinone) compared to allopathic drugs (gemcitabine, olaparib, fluorouracil) against target receptors of pancreatic cancer (human glutamate oxaloacetate transaminase 1 (got1), threonine-protein kinase bub1, and peroxisome proliferator-activated receptor gamma), to what extent does inhaling e-cigarettes affect the lungs’ vital capacity of high school students in jakarta, estudio sobre el efecto de la crema dental utilizada para el cepillado de los dientes como inhibidor en la actividad enzimática de la alfa amilasa salival, how can the frameshift mutation caused by a deletion that affects the human body's melanocortin receptor gene (mcr) and leptin receptor gene (lepr) induce monogenetic obesity, to what extent does high intensity interval training (hiit) effect the maximum oxygen uptake (vo2max) in sedentary populations, investigating the effects of oil spillages on plants, to what extent does varying the duration (0 mins, 5 mins, 10 mins, 15 mins, 20 mins, 25 mins) at which a 25% solution consisting of ethanol-dissolved ayurvedic spices (curcumin and black cumin) is maintained at 60°c affect the antimicrobial activity of these spices against a k12 strain of escherichia coli, what effect do differing concentrations of the growth hormone gibberellic acid, have on the growth and mortality rates of pulses, common beans (phaseolus vulgaris l.) and common peas (pisum sativum l. (partim)), how do different concentrations of two cytokinin hormones: kinetin (0.5, 1 and 1.5 mg/l) and 6-benzylaminopurine (1.5, 2 and 2.5 mg / l) affect the growth of lactuca sativa, measured by height, number of leaves and dry mass, separately and combined over 5 weeks, to what extent is frequent consumption of ultra processed food related to prevalence of overweight and obesity among high school and college students, in poland and in thailand, how does the pollution of oestrogens into freshwater systems affect the biological processes of fathead minnows, to what extent does the abundance of hormosira banksii influence biodiversity at different positions on the intertidal rocky shore, how does the duration of exposure time to ultraviolet light affect the growth of saccharomyces cerevisiae, to what extent do various concentrations of piper betle extract (1%, 2%, 3%, 4%, 5%) affect the enzymatic activity of the digestive enzyme amylase, protease and lipase on their substrates (starch, casein and milk) in the the process of digestion and the estimation of vitamin c concentration in piper betle, ¿cómo los cambios en la luminosidad con niveles de 0, 2 500 y 5 000 lux, en focos de 25 y 50 watts respectivamente, afectan a la fijación de dióxido de carbono (co2) en la sansevieria trifasciata zeylanica biología nm, knowing that fingerprints are always different, but the core is identical, to what extent is it possible to see other similarities between the minutiae of close family members, to what extent does irrigation with carbonated water affect the ferric ion (fe3+) nutrient content of brassica oleracea ‘black tuscany’ microgreens, ¿cómo se estudia el angioedema hereditario, su diagnóstico, tratamiento, síntomas y etiología en humanos, to what extent does the efficiency of lactase enzyme found in different types and brands of dietary supplements (vitaplus innolact lactase dietary supplement film-coated tablet, millandjoy lactase enzyme chewable tablets, lactase comfort drops, dr. chen soft capsule, sanct bernhard lactase enzyme capsule) differ if the prescribed dosage used, measured as the amount of glucose produced after being treated with different supplements in a given time period (30sec, 60sec, 90sec, 120sec, 150sec), how do different concentrations of salicylic acid (1mm and 1m) affect growth of radishes (raphanus sativus), under drought, osmotic and cold stress, as well as normal conditions, the impact of ph on chlorella vulgaris, the effect of sucrose concentration on the percentage change in carbon dioxide during ethanol(yeast fermentation), to what extent does animal rennetassist lactic acid bacteria in the fermentation of milk during the production of cheese curds, what is the effect of seawater mixture (0%, 5%, 10%) on the germination of black chickpeas (cicer arietinum), green gram (vigna radiata) and fenugreek (trigonella foenum-graecum) for 5 days and their subsequent growth when watered using tap water for 10 days where growth was measured by plant height (±0.05 cm) and dry mass (±0.001 g), what is the effect of different light combinations on the movement of semiaquatic turtles, red-eared slider (trachemys scripta elegans) with respect to the position of the light sources, how do different nitrogen-phosphorus-potassium (npk) ratios (1:1:1, 2:1:1, 2:2:1 and water) in aqueous fertilisers affect growth (as measured through a mitotic index) of the onion (allium cepa), over a 5- week period, in a hydroponics set up, to what extent does varying concentrations of the hormone progesterone promote the short term growth of egeria densa.

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What I learned from messing up my biology extended essay

Each year we invite IB alumni to share their experiences, interests and advice with our global community in the  graduate voices  series. We welcome Diploma Programme (DP) graduate Lim Hui Yuan to share some tips and advice to DP students completing their extended essays after completing her DP education at Hwa Chong International School .

By Lim Hui Yuan

I’m sure all the current and past IB students know the hardship of completing an Extended Essay (EE). And for those who are not familiar with EE, it is actually “ an independent, self-directed piece of research ”, which culminates into a 4,000-word paper.

To many (including me), EE was a real boot camp training because of the effort and tenacity it requires one to possess. Well, it was quite daunting a time for me, BUT—I have to admit that I learned a lot from messing up my project. Looking back, the nine months I spent on my EE was indeed an endurance experience.

Here are my takeaways from almost failing my Biology EE. Some of them might be relevant to other EE subjects, but they mainly revolve around the challenges I personally faced.

Knowing what you’re interested in isn’t always that easy

They always say, “follow your heart”

“Pick a project topic that you are interested in.”

Sometimes, we might not even know what our heart wants and where our interests actually lie. We students face a dilemma when choosing an EE subject or topic in the same way we are confused when standing at the junction of deciding which university path to choose.

There is a plethora of topics that we could work on, but not all of them could keep us motivated for more than half a year. I chose, “The Efficacy of Natural Plant Extracts and Commercial Disinfectants in Reducing Bacterial Growth.”

I like to think of it like becoming a gardener. Your project starts off small, you have to nurture it, and once the research topic is settled, it just keeps growing. In the end, you’ll have an EE that has grown from just a tiny seed into a big plant you are really proud of.

Nevertheless, I came to realise that no matter what topic you choose, as long as you pour your heart into it, you will not regret the outcome.

Asking yourself, “ why do I want to do this project?” helps to keep you on the right track (even if the answer was “to get a good grade”).

Failing is more common than succeeding

After diving into my biology EE, I realised how easy it was to carry out experiments in class compared to conducting your research project. There’s no lab manual you can simply refer to. Instead, you have to create your own recipe , adapting from previous work. And since it’s your own custom-made experiment, you can never predict how the results will turn out.

As much as you try to fix the controlled variables, it seems like you can’t control the outcome of the study.

In my case, I expected some of the plant extracts to show antibacterial properties. However, I underestimated how mischievous the bacteria can be, contaminating all my plant samples.

I took the success of the experiment for granted.

This bump went on for over five months. At one point, I was so traumatised by the lack of progress that I couldn’t bring myself into the lab. Frustrated and drained, I was on the verge of giving up.

Here’s when you should take a breather to flush away the negative emotions and reset everything—including your impression of the project itself.

Learn to move on

Just as the wise Ryan Higa mentioned, “ here’s a bridge; now, get over it ”.

Whatever will happen has happened and all you can do is to move on.

After getting yourself ready for a fresh start, you should turn on troubleshoot mode and make amendments to your procedures. Try to pinpoint the problem and then search for plausible solutions to tackle it. The trial and error method is the only way!

Imagine beginning to piece a puzzle together; you usually know what the big picture looks like first before connecting the parts. The same applies to your EE. Plan ahead.

Set mini-deadlines as you draft your action plan. The timeline is essential so that you don’t feel too overwhelmed by a load of work (especially when you have a month left to write your EE after getting your results, which was exactly my case).

Be careful not to be too optimistic with the progress of your experiments. I expected and planned that mine would take at most two months to finish, but I completely neglected some time factors such as time needed for the bacteria to incubate, to make the agar plates, the opening hours of the lab (which leaves me only a few hours after school), and of course , failures.

You may have a supervisor to nag you about your EE progress. However, once you’re out of high school, nobody will be there to alarm you and snoozing off will cost you more than just your grades.

You’re not alone on this

If it weren’t for my EE supervisor and friends, I would’ve given up.

My EE supervisor kept encouraging me and taught me how to endure an initial lack of results, and I’ve learned since then that this is actually a norm of scientific research . One of my best friends, who was also doing a biology EE, took his time to teach me how to write a biology EE amidst his busy schedule (you know who you are, thank you!).

Remember to discuss your difficulties to your advisor or friends; they’ll be your pillar of support.

EE is not only here to prepare you for undergraduate research, but also provide a resilient attitude for life, in general.

Honestly, I’m quite grateful that I faced so many problems during the process. It feels like playing a game with many obstacles and overcoming each hurdle leads you to a higher-level ranking. I am, by no means, a “Legend”, but I’ve certainly passed the “Rookie” level.

P.S. Remember to pat yourself on the back after completing your EE. After all, you’ve shed blood, sweat and tears into raising your seedling into a plant.

Lim Hui Yuan is a graduate of Hwa Chong International School , Singapore. She is currently pursuing her degree in science, specifically a major in Molecular Biology and Biotechnology, at the University of Hong Kong. She likes to experiment with new things and loves dancing and cooking. Also, you can find her binge-watching dramas most of the time.

To hear more from Diploma Programme (DP) graduates check out these  IB programme stories. If you are an IB grad and want to share your story, write to us at [email protected].  We appreciate your support in sharing IB stories and invite you to connect with us on LinkedIn , Twitter and now Instagram !

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Extended essay frame and word citation tool.

Posted by Stephen

Here’s a document we are using in my Extended Essay group . The intention is that students set it up from day 1, keeping all of their reading and research in a section at the end which will allow them to build their citations database. This section of notes will be deleted before final submission, unless any of the resources they save are worthy of an appendix.

By this point, students have read the examiners’ reports for their subject area EE’s, looked at some excellent examples ( on sale in the IB store ) and have read carefully through the EE guide, noting the subject-specific guidance for each criterion.

At the end of the document is a set of rubrics for self-assessment, which they should refer to on a regular basis. I have set it up so that they can add their own checkboxes above each rubric, listing what is most important for them to achieve.

There is a screencast below the document which gives a very quick introduction to using the Word citation manager.

Check out these great resources from Purdue’s OWL project on APA citation .

What I would love to see

If I could make one request of the IB, it would be that rolled into our programme fees for DP we could have access to university-style academic searches and journals. Wouldn’t it be great if the IB subscribed to the journals and schools could access them through Athens or Springerlink (or something else), to use in EE’s and research?

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​Researching and writing an IB Extended Essay in Biology

Mr James Fraser, Head of Science at  Scarborough College , shares some of the Extended Essay topics that he's had the pleasure of supervising.

The Extended Essay is a compulsory component of the IB Diploma. Students are tasked with writing four thousand words on a topic of their choice relating to one of the subjects they are studying for their Diploma. Every student is allocated a supervisor who will guide them through the process. It is not an exaggeration when I say that supervising students completing their Extended Essay in my subject has been the most rewarding part of my teaching role at the College.

I have had the privilege of supervising more than thirty students since the IB was introduced at the College more than ten years ago. When I cast my mind back, some topics and essays immediately spring to mind. For instance, the research undertaken by a student to investigate the response made by the tiny C. elegans worm to being tapped on the head. After we had acquired the worms from the University of Chicago, the student designed an ingenious device to tap the head of the worms using her own eyelash. I am sure the experience of conducting research for her Extended Essay in the College laboratory was an instrumental reason for her choosing to read for an immunology degree at the University of Glasgow before doing a PhD at Melbourne University.

More recently, a student now studying medicine at university, designed an investigation to genetically modify bacteria cultured in the lab with a gene originally obtained from jellyfish. The gene taken up by the transgenic bacteria caused them to fluoresce when exposed to ultraviolet light. The gene was prepared in a number of different ways to see if this had an effect on its uptake by the bacteria.

Our current Upper Sixth students have recently submitted their Extended Essays. A variety of topics were chosen for investigation by biologists this time around including the effect of hair washing on the strength of hair and the frequency of visits to a bird feeder by House sparrows during the day.

Another essay written by Ksenia Ivanova focussed on the potential for the effect of an antibiotic to be enhanced when used in conjunction with a variety of different plant extracts. I asked Ksenia what advice she would give a student choosing a topic for their essay. She replied that 'Whichever topic you decide to explore, the key is to choose something that you really like and care about, so that your work would never be boring.'

The essays themselves are awarded a grade from A to E. Together with the grade for the Theory of Knowledge course, upto three additional IB Diploma points can be included in their overall IB Diploma score. However, the emphasis throughout the process is not solely on the outcome. Many former students have been in touch over the years to tell me how much their Extended Essay experience helped them when completing assignments and dissertations at university. They always comment on the head start they had over their peers who had studied for ‘A’ Levels who had no experience of academic writing at school.

Returning to my current students, they have discovered that the frequency of hair washing does NOT have an effect on its strength, House sparrows visit garden feeders more in the morning and early evening than at other times of day, and are much more likely to be male than female, and the growth of bacteria was inhibited more when an antibiotic was used together with either clove oil or clary sage extracts than when it was used on its own.

Extended Essay Writers

Biology EE Topics | 40 Ideas

Luke MacQuoid

There are many potential topics for a biology Extended Essay (EE) in the International Baccalaureate (IB) program.

Topic Ideas

Some possibilities include the following:

• The effects of pollution on a particular species or ecosystem.
• The genetic basis of a specific disease or trait.
• The comparative physiology of a specific mammal and bird.
• The effects of climate change on a particular species or ecosystem.
• The impact of human activity on the evolution of a species.
• The physiology of a specific plant species.
• The efficacy of a specific medicinal plant.
• The comparison of the anatomy and physiology of a specific animal species in captivity and in the wild.
• The impact of a specific invasive species on an ecosystem.
• The effect of different fertilizers on the growth and development of a specific plant species.
• The study of the symbiotic relationship between specific species.
• The effect of different light conditions on the growth and development of a specific plant species.
• The impact of different temperature conditions on the physiology of a specific microorganism.
• The study of the genetic diversity within a specific species.
• The study of the effects of different pH levels on the growth and development of a specific plant species.
• The impact of human activity on the population dynamics of a specific species.
• The study of the effects of different soil types on the growth and development of a specific plant species.
• The study of the impacts of different pesticides on the physiology of a specific species.
• The study of the effects of different water conditions on the growth and development of a specific plant species.
• The study of the impact of ocean acidification on the physiology of a specific marine species.
• Studying the Effects of Acid Rain on Local Flora.
• The Role of Gut Microbiota in Obesity.
• Influence of Insecticides on Honey Bee Population Decline.
• The Effects of Microplastics on Aquatic Food Chains.
• The Role of Genetics in Determining Human Lifespan.
• Influence of Habitat Loss on the Genetic Diversity of a Specific Species.
• The Effects of Light Pollution on Nocturnal Animals.
• A Comparative Study of Photosynthesis Rates in Different Plant Species.
• The Impact of Noise Pollution on Avian Communication.
• Analysis of Biological Controls for Invasive Species.
• The Effects of Diet on the Gut Microbiota.
• Understanding the Effect of Climate Change on Disease Vectors.
• Exploring the Role of Genetics in Athletic Performance.
• Effects of Pharmaceuticals on Aquatic Ecosystems.
• The Impact of Urbanization on Local Bird Species.
• Understanding the Relationship Between Sleep and Immune Function.
• Studying the Effects of Air Pollution on Lichen Species.
• The Role of Epigenetics in Aging.
• The Effect of Vegan and Vegetarian Diets on the Human Body.
• Investigating the Biological Mechanisms of Meditation and Mindfulness.

It’s important to note that these are just examples of topics for your IB EE in Biology . You should choose a topic that interests you and that you can find enough information on.

Need help with your Biology extended essay?

From research and analysis to structuring and editing, our skilled mentors will be by your side, helping you craft an exceptional extended essay that not only meets the stringent IB criteria but also reflects your passion for Biology studies.

Additionally, it’s essential to consult with your supervisor to make sure the topic meets the requirements of the Extended Essay and that you have access to the necessary resources to complete the research.

Students can use these themes in their essays by researching and analyzing the specific topic, providing evidence and examples to support their claims, and discussing the implications and potential solutions to the issue at hand.

For example, in an essay on the effects of pollution on a particular species or ecosystem, a student could research the specific pollutants that are affecting the species or ecosystem, analyze the effects those pollutants are having, and discuss potential solutions to mitigate the pollution and its effects.

These are experiments students can use for Biology EE topics:

• Looking at how pollution impacts a certain type of animal or plant: This would involve checking out pollution levels in a specific place, then watching to see how it affects your chosen species.
• Understanding how certain genes affect a disease or characteristic: This would mean doing genetic tests to identify the genes involved, and potentially using genetic engineering techniques to change those genes and see what happens.
• Comparing how a mammal and a bird work: You’d do experiments to see how your chosen mammal and bird are similar or different. You could look at things like brain structure, behaviour, and thinking abilities.
• Exploring how climate change impacts a certain animal, plant, or ecosystem: This could involve experiments to see how changes in temperature, rain patterns, or CO2 levels affect your chosen species or ecosystem.
• Studying how people’s actions affect how a species evolves: This might mean looking at how things like habitat destruction, hunting, or pollution impact a species’ genetic diversity and population.
• Looking at how a certain plant works: You’d do experiments to see how the plant responds to things like light, temperature, or water.
• Studying how well a medicinal plant works: You’d do experiments to see how good the plant is at killing or slowing the growth of microbes, or reducing pain or inflammation.
• Comparing a certain animal in captivity and in the wild: You’d look at how being in captivity affects the animal’s body and how it works, and how it behaves.
• Seeing how an invasive species affects an ecosystem: You’d study how your chosen invasive species impacts the growth, reproduction, and health of native species.
• Studying how different fertilizers affect a plant: This could involve testing different types of fertilizers to see how they affect the plant’s growth rate, leaf size, and health.
• Looking at how certain species interact: You’d do experiments to understand the relationship between the species. This could involve seeing what happens when you remove one species, or how different environments affect the relationship.
• Studying how light affects a plant: This might mean doing experiments to see how different light conditions affect the plant’s growth, leaf size, and health.
• Looking at how temperature affects a microorganism: You’d do experiments to see how different temperatures impact the microorganism’s growth rate, metabolism, and health.
• Studying genetic diversity in a species: This could involve using genetic markers to identify genetic variations in the species, and then seeing how these variations affect the organism.
• Looking at how pH levels affect a plant: You’d do experiments to see how different pH levels impact the plant’s growth, leaf size, and health.
• Studying how people’s actions affect a species’ population: This might mean looking at how things like habitat destruction, hunting, or pollution impact the species’ population size, growth rate, and health.
• Looking at how soil types affect a plant: This could involve doing experiments to see how different types of soil affect the plant’s growth, leaf size, and health.
• Studying how pesticides affect a species: This might mean doing experiments to see how different pesticides impact the species’ growth, reproduction, and health.
• Looking at how water conditions affect a plant: You’d do experiments to see how different water conditions (like availability, salt levels, or temperature) affect the plant’s growth, leaf size, and health.
• Studying how ocean acidification affects a marine species: This could involve doing experiments to see how increasing acidity levels impact the species’ growth, reproduction, and health.

Additionally, in an essay on the comparative psychiatry of a specific mammal and bird, a student could research and compare the brain structures, behaviors, and cognitive abilities of the two species and discuss any similarities and differences found.

A student can ask for help from a writing service if they need assistance with their essay. This can bring several benefits to the student, such as:

• Professional guidance . Writing services often have experienced writers and editors who can provide guidance on the essay topic and structure, as well as help with research and editing.
• Improved quality . A writing service can help improve the overall quality of the essay, including grammar, punctuation, and formatting.
• Better grades . With the help of a writing service, a student’s essay is likely to be of higher quality, which can lead to better grades.
• Time-saving . A writing service can help save time as the student can focus on other responsibilities while the writing service works on the essay.
• Customization . Writing services can also provide a customized service that can be tailored to the student’s specific needs and requirements.
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It is important to note, however, that a student should always ensure that the writing service they use is reputable and that they review and understand the work they receive before submitting it as their own.

Luke MacQuoid has extensive experience teaching English as a foreign language in Japan, having worked with students of all ages for over 12 years. Currently, he is teaching at the tertiary level. Luke holds a BA from the University of Sussex and an MA in TESOL from Lancaster University, both located in England. As well to his work as an IB Examiner and Master Tutor, Luke also enjoys sharing his experiences and insights with others through writing articles for various websites, including extendedessaywriters.com blog

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Higher Human Biology: Extended Response Questions/Markschemes

Description.

• human biology
• extended response
• physiology and health
• neurobiology and communication
• immunology and public health
• human cells

Resource summary

Human cells.

Compare the location and functions of embryonic and tissue (adult) stem cells. (7) 1. Stem cells are undifferentiated cells capable of repeated division to both more stem cells and cells that will later differentiate to form specialised cells. 2. Embryonic stem cells (ESCs) are found in the inner cell mass of the blastocyst. 3. ESCs are capable of repeated division… 4. …to form more ESCs and other cell types. 5. ESCs are: capable of forming all the other cell types of the body / pluripotent 6. Tissue stem cells (TSCs) are found throughout the juvenile and adult body. 7. TSCs are capable of repeated division to form more TSCs and other cell types. 8. TSCs: can only form cells of the organ to which they belong / are multipotent. 9. e.g. bone marrow tissue cells can only give rise to bone marrow cells, red blood cells, platelets, phagocytes and lymphocytes. Give an account, with examples, of the different body tissue types and their functions. (8) 1. Body tissue cells derive from somatic stem cells … 2. … by repeated mitosis. 3. Epithelial tissue - covers the organ surfaces. 4. Protection - skin / secretion - intestinal glands / absorption - villi. 5. Connective tissue - gives shape to organs and supports them. 6. Protection - skull bones / structural framework - ribs / storage of energy - adipose tissue / connecting body organs - blood / connecting epithelial to muscle tissue - cartilage (in tendons) 7. Muscle tissue - which causes locomotion or movement within organs. 8. Skeletal muscle - locomotion / smooth muscle - in arterioles control of access to capillary bed / cardiac muscle - contraction of the heart. 9. Nervous tissue - which transmits messages between the central nervous system and the rest of the body (and within the central nervous system). 10. Neurons - conduct impulses / glial cells - maintain a constant environment for neurons. Describe the way in which the use of stem cells has contributed to: A. corneal transplants; (3) B. skin grafts. (3) A. Corneal transplants: 1. Traditionally, the person would have to wait for donated corneal tissues to become available. 2. With the use of stem cells isolated from the patient's healthy eye, new tissue can be cultured… 3. …which can be transplanted back into the damaged eye, 4. and will repair the damaged corneal epithelium. B. Skin grafts: 1. Traditionally, a section of the patient's healthy skin is cultured over 3 weeks. 2. During this time, dehydration and infection are risks for the patient. 3. Skin stem cells from the patient can be cultured to produce new epidermal cells much more quickly. 4. This reduces the time during which the patient is at risk. A. Describe the location and structure of DNA. (8) B. Give an account of the replication of DNA. (7) A. Describe the location and structure of DNA.(maximum of 8 marks): 1. DNA is located on chromosomes in the nucleus. 2. A DNA molecule consists of two strands wound in a double helix. 3. Each strand consists of subunits called nucleotides. 4. A nucleotide consists of a deoxyribose sugar molecule, a phosphate group and an organic / nitrogenous base. 5. The deoxyribose and phosphate are linked to their neighbours to form a sugar-phosphate backbone. 6. There are four organic bases: adenine (A), thymine (T), guanine (G) and cytosine (C). 7. Bases are linked in complementary pairs A-T and G-C. 8. Bases link the two DNA strands by hydrogen bonds. 9. The two DNA strands have an antiparallel structure / explanation. 10. Deoxyribose is found at the 3′ end of each strand and phosphate is found at the 5′ end. B. Give an account of the replication of DNA.(maximum of 7 marks): 1. DNA is unwound and unzipped… 2. …by the enzyme helicase… 3. …to form two template strands. 4. DNA polymerase is the enzyme which adds nucleotides to the new DNA strand. 5. DNA polymerase needs a primer to start replication. 6. DNA polymerase can only add complementary nucleotides to the deoxyribose / 3′ end of the DNA strand. 7. This results in one strand / the leading strand being continuously replicated, 8. and the other strand / the lagging strand being replicated in fragments, 9. which are joined together (by the enzyme ligase). Give an account of the structure and function of proteins. (8) A. Protein structure (maximum of 4 marks): 1. Proteins consist of amino acids joined together (in chains). 2. The amino acids are joined by strong peptide bonds… 3. …to produce the primary structure of the polypeptide. 4. Further bonding between amino acids… 5. …produces the secondary and tertiary structures. 6. Folding of the polypeptide chains forms the three-dimensional shape of the protein. B. Protein function (maximum of 4 marks): 1. Some proteins are enzymes + named example (e.g. the digestive enzyme amylase). 2. Some proteins are hormones + named example (e.g. insulin). 3. Some proteins are antibodies which help the body fight infections. 4. Some proteins transport substances + named example (e.g. haemoglobin). 5. Some proteins provide structure + named example (e.g. collagen). Give an account of gene expression under the following headings. A. Transcription (6) B. Post-translational modification (PTM) (4) A. Transcription (maximum of 6 marks): 1. Transcription is the formation of a mRNA molecule on a DNA template. 2. DNA unwinds, and strands separate by the action of helicase. 3. RNA nucleotides attach to exposed bases of DNA. 4. DNA A pairs with RNA U, DNA T - RNA A, DNA G - RNA C and DNAC - RNA G. 5. RNA polymerase joins nucleotides (to each other). 6. This produces the primary transcript. 7. Which contains introns and exons. 8. Exons are protein coding sections of mRNA and introns are non-coding sections. B. Post-translational modification (PTM) (maximum of 4 marks): 1. It takes place after the polypeptide has been completed on the ribosome. 2. It allows several proteins to be formed from one gene. 3. It may involve enzyme cutting and combining of polypeptide chains. 4. e.g. insulin from pro-insulin. 5. It may involve adding of phosphate or carbohydrate groups. 6. Addition of phosphate enables enzymes / receptors to be switched 'on' and 'off'. Give an account of gene mutation. (9) 1. A gene mutation is a change in the base type or sequence in a gene. 2. In a substitution (mutation) one base is replaced by another. 3. If substitution produces a new stop codon it is a nonsense mutation. 4. If substitution affects introns and exons it is a splice-site mutation. 5. If substitution changes one mRNA codon it is a missense mutation. 6. In a deletion (mutation) a base is removed. 7. In an insertion (mutation) a base is added. 8. A change to a single nucleotide / base is a point mutation. 9. Insertion and deletion (mutations) can potentially cause frameshift mutation. 10. A frameshift mutation alters all the triplets following it. 11. If any of these mutations occurs in a protein-coding gene, then the protein produced may be altered (or not produced at all). Give an account of the amplification of DNA sequences by the Polymerase Chain Reaction (PCR). (8) 1. The components of the PCR (template DNA, primers, nucleotides and the Taq DNA polymerase) are mixed together. 2. Heating to 90 - 95°C… 3. …separates (denatures) the double-stranded DNA (containing the target DNA sequence). 4. Annealing at 54°C… 5. …allows the primers to bind (by forming hydrogen bonds) to their complementary sequences on the separated strands 6. Primers are short DNA sequences (each about 20 bases long), 7. that bind at either side of the target sequence (one on each of the complementary strands of the target DNA). 8. Extension at 72°C. 9. Taq polymerase now adds nucleotides to the 3′ ends of the primers and extends them into new complementary strands. 10. Repeated cycles multiply the target DNA exponentially… 11. …since each new double strand separates to become two templates for further synthesis. Describe the control of the action of enzymes which are continuously present in the cell. (10) 1. Enzymes that are in constant use are continuously present. 2. The presence of the substrate may initiate a reaction. 3. The build-up of the product may reverse the direction of a reaction. 4. The active site is the part of the enzyme molecule to which the substrate (temporarily) binds. 5. Competitive inhibitors resemble the substrate and compete with it for the active site. 6. Increased substrate concentration reduces the effect of competitive inhibition. 7. Competitive inhibition is reversible. 8. Non-competitive inhibitors bind to allosteric sites… 9. …and alter the shape of the sites, preventing the substrate from binding to them. 10. Enzyme activators bind to allosteric sites and alter the shape of the active site to fit the substrate. 11. Feedback inhibition involves non-competitive inhibition. 12. Products from reactions late in metabolic pathway act as non-competitive inhibitors to enzymes earlier in the pathway. State what is meant by the term 'feedback inhibition', give an example of it, and explain its advantage to the cell. (7) 1. Feedback inhibition in a metabolic pathway occurs when an enzyme's activity is reduced… 2. …by an increase in the concentration of a product from a later step in the pathway. 3. In the energy investment stage of glycolysis… 4. …phosphofructokinase is inhibited by ATP… 5. …which is released by glycolysis and the cytochrome system. 6. If the ATP concentration rises in the cell, phosphofructokinase will become less active… 7. …and the production of ATP will be reduced, or vice versa. 8. The production of ATP will be matched to the cell's need for energy… 9. …and resources will be conserved. Give an account of the enzymes and coenzymes involved in the citric acid cycle. (6) 1. Each step in the citric acid cycle is mediated by a different enzyme. 2. Dehydrogenase enzymes remove hydrogen and electrons. 3. Coenzymes NAD / NAD+ and FAD accept hydrogen and electrons. 4. NAD / NAD+ accepts hydrogen to form NADH. 5. FAD accepts hydrogen to form FADH2. 6. NADH / FADH2 / reduced coenzymes carry hydrogen and electrons to the electron transport chain… 7. …which results in the generation of ATP. Give an account of the electron transport chain. (8) 1. NADH and FADH2 carry H+ ions and high energy electrons… 2. …from glycolysis and the citric acid cycle. 3. At the inner mitochondrial membrane, NADH and FADH2 pass the hydrogen ions and high energy electrons… 4. …to carriers in the electron transport chain. 5. The electron transport chain is a collection of proteins attached to the inner mitochondrial membrane. 6. As the high energy electrons released from NADH and FADH2 pass along the chain, … 7. …they release their energy in stages. 8. This energy is used to pump H+ ions into the intermembrane space. 9. The final electron acceptor is oxygen. 10. The (negatively charged) oxygen combines with two H+ ions to form water. Give an account of the role of creatine phosphate in muscles. (8) 1. Muscle cells do not contain any reserves of ATP which will fuel more than 2s of activity. 2. Creatine phosphate is an energy reserve found in cells with high and variable energy demands… 3. …such as muscle / brain. 4. Creatine phosphate is used by fast twitch muscle fibres. 5. Creatine phosphate breaks down anaerobically… 6. …to release energy and phosphate… 7. …which is used to convert ADP and Pi to ATP at a fast rate. 8. There is only sufficient creatine phosphate to fuel strenuous muscle activity for a maximum of 10s. 9. When energy demands are low, creatine phosphate reserves are restored… 10. …using ATP provided by aerobic respiration.

Physiology and Health

Describe:A. the development of ova in the ovary; (6)B. and their possible fates after ovulation. (2)A. Development of ova in the ovary (maximum of 6 marks):1. The ovary contains many immature ova.2. Each ovum develops in a follicle.3. Follicles protect the ova.4. Follicles secrete hormones / oestrogen.5. Every 28 days, a (mature) follicle moves to the surface of the ovary.6. An ovum is released into the oviduct.7. The follicle develops into the corpus luteum…8. …which releases hormones / progesterone.B. After ovulation (maximum of 2 marks):1. The ovum may be fertilised to form a zygote.2. The fertilised ovum / zygote divides many times to form the blastocyst.3. The blastocyst implants in the endometrium.4. Unfertilised ova pass out of the body.Give an account of negative feedback control under the headings:A. testosterone production; (3)B. the luteal phase of the menstrual cycle. (3)A. Testosterone production (maximum of 3 marks):1. The pituitary gland releases LH/ICSH.2. LH stimulates the interstitial cells of the testes to release testosterone.3. Increasing level of testosterone inhibits/reduces the production/release of LH.4. Pituitary gland releases less LH…5. …so testes/interstitial cells release less testosterone.B. The luteal phase of the menstrual cycle (maximum of 7 marks):1. After ovulation, the high level of LH causes the follicle to develop into the corpus luteum.2. The corpus luteum secretes progesterone and oestrogen.3. During this phase the secretion of oestrogen and progesterone rise to a maximum and then decline.4. The high levels of oestrogen inhibit the pituitary from secreting FSH.5. The high levels of progesterone inhibit the pituitary from secreting LH.6. The resulting low level of FSH suppresses the development of further follicles.7. The low level of LH causes the corpus luteum to degenerate…8. …and progesterone secretion to fall to a minimum.9. The falling level of progesterone at the end of the cycle triggers the start of menstruation.10. The low level of oestrogen at the end of the cycle causes the pituitary to increase secretion of FSH.Give an account of fertile periods under the headings:A. men; (4)B. women. (6)A. Men (maximum of 4 marks):1. Men are fertile from puberty to death.2. Fertility does decrease with age.3. Men are continuously fertile / produce sperm constantly.4. Testosterone stimulates sperm production.5. Testosterone production is stimulated by ICSH from pituitary.6. Testosterone and ICSH interact in a negative feedback loop.B. Women (maximum of 6 marks):1. Women are fertile from puberty to the menopause / age 45 - 55.2. Women are cyclically fertile.3. Only fertile for a few days each month around time of ovulation.4. Ovulation is stimulated by a surge in LH secretion.5. LH is secreted by the pituitary gland.6. Oestrogen and progesterone from ovary interact in a negative feedback loop…7. …with FSH and LH from the pituitary.8. Time of ovulation can be determined by recording body temperature and cervical mucus.9. Fertile period lasts from a few days before to a few days after ovulation.Give an account of the tests which can be carried out once a woman has been confirmed as pregnant, under the headings:A. screening tests; (6)B. diagnostic tests. (4)A. Screening tests (maximum of 6 marks):1. Screening indicates possibility of a condition.2. Ultrasound dating scan at 8-14 weeks…3. …indicates age of fetus / likely due date.4. Ultrasound anomaly scan at 18-20 weeks…5. …indicates possible unusual development, associated with e.g. Down's syndrome.6. Biochemical tests on blood samples.7. Levels of marker chemicals inappropriate to stage of pregnancy, e.g. α-feto protein…8. …indicate possible presence of Down's syndrome.B. Diagnostic tests (maximum of 4 marks):1. Diagnostic tests confirm the presence of condition.2. Amniocentesis removes cells from the amniotic fluid…3. …and are carried out at about 18 weeks4. Chorionic villus sampling removes cells from the placenta…5. …and are carried out at 10-12 weeks.6. Karyotyping - examination of fetal chromosomes.Give an account of the exchange of materials between the blood and the body tissues under the headings:A. movement of fluid in and out of the blood; (6)B. substances transferred. (4)A. Movement of fluid in and out of the blood (maximum of 6 marks):1. Exchange only occurs in the capillaries / capillary beds.2. Fluid moves because of pressure differences.3. Fluid leaves blood because hydrostatic pressure exceeds osmotic pressure.4. Fluid re-enters blood because osmotic pressure exceeds hydrostatic pressure.5. Fluid leaves capillaries by pressure filtration.6. The capillary walls determine what may pass through them.7. Fluid entering the tissues is called tissue fluid.8. Tissue fluid is similar to blood plasma but lacks plasma proteins.B. Substances transferred (maximum of 4 marks):i. All substances in the blood except cells and large protein molecules pass out into tissue fluid.ii. Tissue fluid supplies cells with oxygen, glucose, amino acids, fatty acids, hormones, mineral ions. (any 2 for 1 mark, any 4 for 2 marks)iii. Waste materials from cells are passed back into the blood + any example, e.g. CO2, lactic acid. (full mark requires an example)iv. Products of cells are passed back into the blood + any example, e.g. hormones. (full mark requires an example)v. Excess / 10% tissue fluid passes into the lymphatic system.Give an account of the cardiac cycle under the following headings:A. atrial systole; (3)B. ventricular systole; (5)C. diastole. (2)A. Atrial systole (maximum of 3 marks):1. During atrial systole, the sino-atrial node / pacemaker, sends waves of nerve impulses across the walls of the atria…2. …which makes them contract simultaneously.3. The pacemaker is situated in the wall of the right atrium.4. Blood is forced through the atrio-ventricular/AV valves into the ventricles.B. Ventricular systole (maximum of 5 marks):i. The SA node also stimulates the atrio-ventricular (AV) node…ii. …which is situated between the atria and the ventricles.iii. The AV node sends nerve impulses down the septum and into the walls of the ventricles…iv. …making them contract simultaneously…v. …from the bottom up, which is the most efficient way of emptying them.vi. As the ventricles contract the AV valves close…vii. …preventing backflow of blood (into the atria).C. Diastole. (maximum of 2 marks):I. During diastole the atria and ventricles relax.II. The semi-lunar valves close.III. The AV valves open to allow blood to pass into the ventricles (again).Give an account of cholesterol in the body under the headings:A. sources and removal of cholesterol; (3)B. high density lipoproteins and low density lipoproteins. (7)A. Sources and removal of cholesterol (maximum of 3 marks):1. Cholesterol is formed in all body cells.2. The liver is the greatest producer.3. Cholesterol is present in animal foods e.g dairy products / meat / poultry / fish.4. Cholesterol is eliminated from the body in the bile.B. High density lipoproteins and low density lipoproteins(maximum of 7 marks):i. Lipoproteins are made in the liver.ii. They are responsible for the transport of cholesterol.iii. High density lipoproteins (HDLs) carry cholesterol from the body cells to the liver.iv. Low density lipoproteins (LDLs) carry cholesterol from the liver to body cells.v. LDLs attach to LDL-receptors on the cell membrane of most cells.vi. The production of LDL-receptors is controlled by negative feedback.vii. LDLs are carried into the cells to release their cholesterol.viii. Excess LDLs circulate in the blood and can become absorbed into the atheromas in plaques on artery walls.ix. A high ratio of HDLs to LDLs lowers the level of cholesterol in the blood…x. …reducing the development of atherosclerosis.Give an account of Type 2 diabetes under the headings:A. causes; (2)B. effects; (6)C. diagnosis and treatment (2)A. Causes (maximum of 2 marks):i. Type 2 diabetes results from reduced cellular sensitivity to insulin……ii. …caused by a reduction in the number of insulin-receptors on liver cells.iii. It is associated mainly with increasing obesity in adulthood.B. Effects (maximum of 6 marks): Diabetes of all forms means that the body is unable to control the rise in blood glucose levels after meals. Diabetics have chronically high blood glucose levels… …which damage blood vessels walls. This leads to the development of vascular diseases in large blood vessels… …e.g. atherosclerosis / stroke / myocardial infarction. In small blood vessels of vulnerable tissues it can cause haemorrhaging in the retina, resulting in reduced vision / damage to the glomeruli, resulting in renal failure / slowing down of impulses in the peripheral nervous system, resulting in loss of control and sensation. (1 mark for naming a cause and 1 additional mark for naming the resultant effect) C. Diagnosis and treatment (maximum of 2 marks) Diabetes is diagnosed by a glucose tolerance test… …which involves blood tests taken before, and 2 hours after taking a drink containing 75g of glucose. The patient should have fasted for 8 hours before the test. Treatment is usually administered by adjusting diet… …reducing energy intake and increasing exercise levels.

Neurobiology and Communication

Give an account of the nervous system under the headings:A. divisions of the nervous system; (5)B. homeostatic control. (5)A. Divisions of the nervous system(maximum of 5 marks):1. The nervous system is divided into the central nervous system and the peripheral nervous system.2. The central nervous system consists of the brain and spinal cord.3. The peripheral nervous system comprises all the sensory and motor neurons which connect it to the rest of the body.4. The peripheral nervous system is sub-divided into the somatic and the autonomic nervous systems.5. The somatic nervous system controls the voluntary activity of the skeletal muscles (and thus all movement) via its sensory and motor neurons.6. The autonomic nervous system is further divided into the sympathetic and the parasympathetic nervous systems, which act antagonistically.B. Homeostatic control (maximum of 5 marks):i. The autonomic nervous system plays an important part in many involuntary homeostatic processes…ii. …by conducting impulses through its sensory and motor neurons to the smooth muscle of artery walls, the cardiac muscle of the heart, and to glands.iii. The sympathetic nervous system prepares the body for action, 'fight or flight'…iv. …by speeding up heart and breathing rates, and slowing down peristalsis and intestinal secretions.v. The parasympathetic nervous system calms the body down, 'rest and digest'…vi. …by slowing down the heart and breathing rates, and increasing peristalsis and intestinal secretions.Give an account of Short-Term Memory under the headings:A. increasing memory span; (3)B. serial position effect; (5)C. transfer from STM to LTM. (2)A. Increasing memory span (maximum of 3 marks):1. Memory span is the number of items that can be retained in STM.2. The normal short-term memory span is 7± 2 items.3. Information is retained in STM for 15-30s.4. 'Chunking' helps short-term memory in particular as several items are grouped as one.B. Serial position effect (maximum of 5 marks):i. A large number of items is shown briefly to the subjects so that they cannot all be retained in short-term memory.ii. Items recalled by the subjects are recorded.iii. Subjects usually recall items presented early and late in the series.iv. Items at the end of the series are still retained in STM (the recency effect).v. Items from the start of the series have been transferred to long-term memory (primacy effect).vi. Items from the middle of the list have been displaced from STM…vii. …and have not been transferred to LTM.C. Transfer from STM to LTM (maximum of 2 marks):1. Rehearsal - repetition of information.2. Elaboration of meaning by linking to other memories/emotions.3. Organisation - linking to other similar memories.Compare and contrast sensory and motor neurons and describe events that occur at a synapse. (10)1. Sensory neurons pass messages from sense organs to the central nervous system whereas motor neurons transfer messages from the CNS to muscles and glands.2. Both neurons consist of cell body, axon and dendrites.3. The cell body is found part way along the axon of a sensory neuron, whereas the axon grows out from one side of the cell body in the motor neuron.4. In each case, the axon is wrapped in a myelin sheath with nodes every few millimetres.5. At a synapse, neurotransmitters cross from the pre-synaptic neuron to the post-synaptic neuron.6. Neurotransmitters include acetylcholine and noradrenaline.7. The type of receptor on the post-synaptic dendrite, to which the transmitter chemical binds, determines whether the next neuron is inhibited or excited.8. Acetylcholine is immediately degraded by an enzyme.9. Noradrenaline is reabsorbed by active uptake.10. Synapses filter out single weak impulses, but can sum several weak impulses.Give an account of the mode of action of recreational drugs (with examples), under the headings:A. effects on the brain; (4)B. modes of action. (6)A. Effects on the brain (maximum of 4 marks):1. Recreational drugs mainly affect the reward circuit of the brain…2. …by stimulating increased secretion of dopamine…3. …which causes feelings of euphoria and relaxation…4. …and leads quickly to addiction.5. The changed neurochemistry leads to changes in mood / cognition / perception / behaviour. (mention of all four examples gains this mark)B. Modes of action (maximum of 6 marks): Stimulation of release of neurotransmitter, … …e.g. MDMA stimulates release of serotonin. Agonists , imitating the action of a neurotransmitter, … …e.g. cannabis binds to cannabinoid receptors and suppresses GABA secretion. Antagonists bind to receptors and prevent neurotransmitter from doing so, … …e.g. ethanol binds to GABA receptors and depresses impulse generation. Inhibiting re-uptake of neurotransmitter, …v …e.g. cocaine blocks the re-uptake of serotonin / norepinephrine / dopamine. Inhibiting neurotransmitter degradation, … …e.g. tobacco contains two MAO inhibitors which suppress dopamine breakdown. Describe ways in which humans communicate under the headings:A. non-verbal communication; (4)B. verbal communication. (6)A. Non-verbal communication (maximum of 4 marks):1. Non-verbal communication involves gestures, signs, facial movements and posture.2. Non-verbal communication aids verbal communication.3. Attitudes and emotions are signalled by non-verbal communication.4. Mirroring of non-verbal communication strengthens bonds.5. Examples of non-verbal communication include winking, folding arms and smiling. (three listed for one mark)6. Any two examples explained in terms of meaning conveyed.B. Verbal communication (maximum of 6 marks): Language uses symbols to represent information Language enables information to be organised into categories and hierarchies. This organisation of information accelerates learning. Organisation of information aids intellectual development. The ability of humans to communicate verbally has resulted in the transmission of knowledge. (plus explanation) The ability of humans to communicate verbally has resulted in the development of culture. (plus explanation) The ability of humans to communicate verbally has resulted in social evolution. (plus explanation) The ability of humans to communicate verbally has resulted in the transmission of knowledge, development of culture and social evolution. Give an account of group behaviour and social influence under the headings:A. social facilitation; (3)B. deindividuation; (4)C. influences that change beliefs. (4)A. Social facilitation (maximum of 3 marks):1. Performance of a task may be improved in the presence of others.2. The presence of others in a competitive situation may enhance performance3. Detailed example of the point above4. The presence of an audience may improve performance.5. Detailed example of the point aboveB. Deindividuation (maximum of 4 marks): Deindividuation is responsible for the loss of identity in a crowd. Detailed example of the point above Deindividuation leads to diminished restraints on behaviour. Deindividuation leads to behaviour which would not be shown by individuals on their own. Detailed example of the point above C. Influences that change beliefs (maximum of 4 marks): Internalisation is the changing of one's beliefs as a result of persuasion. Detailed example of the point above Identification is the changing of one's beliefs to those of an admired influencing source. Detailed example of the point above

Immunology and Public Health

Give an account of the inflammatory response. (8)1. Mast cells…2. …release histamine.3. Histamine causes vasodilation…4. …and increases capillary permeability.5. Mast cells also secrete cytokines.6. Cytokines act as signalling molecules.7. The increased blood flow and the secretion of cytokines lead to…8. …the delivery of antimicrobial proteins…9. …and clotting elements to the site of infection/damage.Give an account of clonal selection theory. (6)1. Clonal selection theory explains the way in which lymphocytes are developed to respond to specific antigens which invade the body.2. Antigens are molecules on the surface of pathogens and other foreign cells or materials which activate the immune system.3. Lymphocytes have a single type of receptor on the cell membrane.4. This receptor is specific to one antigen.5. Antigen binding leads to repeated lymphocyte division…6. …which results in a clonal population of lymphocytes.Describe the role of community responsibility in the control of the spread of pathogens. (6)1. Quality of water supply - drinking water must be safe to drink.2. Not contaminated with sewage.3. Free from harmful chemicals and bacteria.4. Supervision of food chains - enforcing minimum hygiene standards.5. In abattoirs, restaurants, fast-food outlets, supermarkets, market stalls. (any two)6. Health education.7. Waste disposal - refuse collection.8. Sewage treatment.State the aim of public health immunisation programmes and explain why they may fail to protect non-immunised individuals. (6)1. Public health immunisation programmes seek to establish herd immunity to a number of diseases.2. Herd immunity occurs when a large percentage of a population are immunised.3. This percentage is called the herd immunity threshold.4. Non-immune individuals are protected because there is a lower probability they will come into contact with infected individuals.5. Difficulties arise when widespread vaccination is not effective because of malnutrition, which weakens the immune system…6. …or poverty, which reduces vaccination rates…7. …or a vaccine being rejected by a percentage of the population.

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Extended Essay: Sciences: Sports, Exercise, and Health Sciences

• Step 1 - Choosing a Subject
• Step 2 - Choosing a Topic
• Step 3 - Draft a Research Question
• Step 4 - Finding Sources
• Step 5 - Evaluating Information
• Step 6 - Bibliography & Citation
• Step 7 - Organizing Information
• The Arts: Visual Arts
• Individuals & Societies: Business Management
• Individuals & Societies: History
• Individuals & Societies: Psychology
• Language Acquisition
• Language and Literature
• Sciences: Biology
• Sciences: Sports, Exercise, and Health Sciences
• Interdisciplinary Papers: World Studies
• Assessment Criteria

Extended Essays in Sports, Exercise, and Health Sciences

Choosing a Topic

All EEs in the sciences should begin with at least one hypothesis based on their research question. An extended essay in sports, exercise, and health sciences  covers a wide range of topics from human physiology to biomechanics. It is an applied science course so an EE in this subject must investigate a sporting or health-related issue using the principles of science .

Extended essays in sports, exercise, and health sciences must have a clear SEHS emphasis. This incorporates knowledge from a variety of fields, in particular biology, chemistry, physics and psychology, but the essay must focus on human health and performance in relation to sport and exercise.

The topic must allow for an approach that relates specifically to:

• human performance in sport or exercise, or
• an understanding of the role of exercise or nutrition in improving or maintaining health and managing disease.

Approaches to Research

Research in SEHS

Then, a student will conduct either primary or secondary research to test their hypothesis by collecting some kind of data. By analyzing their findings a student should be able to find a scientific answer to their research question.

Sports Exercise and Health Sciences Sources

Sports, Exercise, and Health Sciences Sources

Even students doing primary research will still need to reference secondary sources. And students relying entirely on secondary sources will need to find sources not only of written information but also experimental data which they can analyze.

Writing the Essay

An essay in the sciences requires is more than just generating and presenting data. Analysis of the data is also essential. The main body of the essay should consist of an argument or evaluation based on the data or information presented . You can gather your own data through a variety of methods, or rely on secondary data. You should use graphs, tables, or diagrams to point out the significance of your findings.

You should ensure that the main body of the essay is well structured and has an obvious logical progression. You can use numbered and headed paragraphs to impose a clear structure. Your evaluation should show that you understand the the data they have collected and its significance to the world.

In your analysis, you should also describe and explain the limitations imposed on the research by factors such as

• the suitability and reliability of the sources accessed
• accuracy and precision of measuring equipment
• sample size
• validity and reliability of statistics

Students  should also consider biological limitations such as:

• those arising from the problem of repeatability and control when using living material
• the difficulties of generalizing from research based on a single type of organism or environment.

Exceptions for Safety and Academic Honesty

Safety and Ethics in Choosing a Topic

In all cases where human subjects are used as the basis for an investigation, clear evidence of informed consent must be provided in accordance with the IB guidelines.

Some topics may be inadmissible because their means of investigation are unethical. For example, investigations that:

• are based on experiments likely to inflict pain on, or cause stress to, living organisms
• are likely to have a harmful effect on health, eg culturing micro-organisms at or near body temperature (37°C)
• involve access to, or publication of, confidential medical information.

Some topics may be unsuitable because of safety issues. Adequate safety apparatus and qualified supervision is required for experiments involving dangerous substances such as:

• toxic or dangerous chemicals
• carcinogenic substances
• radioactive materials.

Other topics may be unsuitable because the outcome is already well known and documented in standard textbooks.

Assessed Student Work

• A study of the effects of Mindfulness Meditation Therapy (MMT) on accuracy in competitive 10 metre Air Pistol Shooting
• What can influence a better reaction time in martial artists?
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EE in Human Biology - Help with Topic

By shwareb June 9, 2012 in Extended Essay

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In about a week I would need to have chosen what I´m going to do for my EE in Biology and I need to have written a preliminary research question!

Personally I would really like to do it in something that has to do with human biology but my supervisor advised me not to, arguing that there are many variables that one can´t control which ultimately would lead to a bad essay and a bad grade.

Nevertheless, do you guys have any advice on what I could research which has to do with the human body and still achieve a good grade (as with all students I´m aiming for an A).

I´m very interested on how drugs affect different mechanisms of the body. I also have a huge interest in the heart and brain as well as the human digestive system, so a research topic which deals with these areas is very desirable.

P.S. - I have read the EE Guide provided by the IB

Thanks In Advance

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Unfortunately you do have to come up with your own EE title - we cannot do it for you. It's one of the hardest parts of doing an EE and as you are marked on it, it would be cheating for us to assist you in any way other than critiquing your own ideas. I suggest you think of possible experiments which are plausible in a school setting and without causing any ethical problems, and move from there, as experiments involving physiology which can be done in that setting and fulfilling the IBO's ethics criteria are few and far between - this is by far the largest barrier to a human physiology based EE.

• 2 weeks later...

Thank you for your answer!

Our school extended the deadline to when we have to decide what to do for our extended essay, and now I´m thinking about doing it in chemistry.

What do you think universities prefer, that I do it in chemistry or biology for medicine?

Thank you for your answer! Our school extended the deadline to when we have to decide what to do for our extended essay, and now I´m thinking about doing it in chemistry. What do you think universities prefer, that I do it in chemistry or biology for medicine?

To my knowledge, unless you do something very exceptional such as an experiment which is University-level research in a proper lab and you can trot it out at an interview (which basically applies only if you have friends or relatives working in a lab who will help you, or can somehow persuade them to let you onto a project as a school student), then they don't much care what you do your EE in. I would do your EE in the subject you like best as it's likely this will mean you produce a very high-scoring EE. It's so much easier to write if you have a genuine interest in what you're doing. Whether that's Biology, Chemistry-- or something else!

Working in a lab for your EE is a bonus you can bring up in an interview, but that's all. The subject of your EE isn't really that important.

Thanks for your answer!

Chemistry is very much my strongest subject, but I always thought doing it in biology would be better (I´m very good in biology aswell) since I was thinking about doing it on the human body.

My research question in bio is:

How does four different linaments (two which cause a cooling sensation, two which causes the skin to warm up) affect the blood flow in the skin of applied area in 30 different people (15 men, 15 women) from the age of 17-22?

Alternatively 50 men, 10 from the following "age categories": 18-23, 24-30, 45-50, 55-60, 65-70

Is it good enough, can you go in depth with the problem and produce some good results?

What should I expect in terms of result?

Any liniments which you can recommend?

I´ve tried to search on the internet for facts, but in my opinion then don´t go enough in depth?

Should I buy this ?

I feel quite worried about the EE now...

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Guiding student ideas towards biological extended essays

Sunday 17 January 2016

I recently had a student approach me to see if she could do an EE on, "The effect of food that you eat on your mood" . I think it was inspired by a film called, "Super size me". She was interested in doing a questionaire of how satisfied / how healthy people felt after eating fast food outside school and after a lunch in the school canteen. It's an interesting idea, but a bit more psychology than biology. It would be impossible to control all the variables to make a meaningful biological experiment and questionaires frankly scare me to death in an extended essay. Apart from the obvious benefits of getting out of school for an hour with your friends we couldn't think of a biological mechanism which would explain why a burger and fries should make you happier than school canteen food.

I guess that a neuroscientist might be able to use fMRI scans to map the brain activity while eating each type of food under strictly controlled conditions or they might measure dopamine levels instead. Sadly we don't have these facilities in my school yet. For me, to tell the difference between biology and psychology I would ask, "Is there a biological mechanism, based on physiology which underpins the hypothesis?" If the answer is yes then it's more biology than psychology.

Whether it's biology or physchology doesn't matter so much in an extended essay as the need for the student to have a testable hypothesis and an argument which can be developed following the collection of data from a well controlled biology experiment.

Whether it's biology or physchology doesn't matter so much in an extended essay as the need for the student to have a testable hypothesis and an argument which can be developed following the collection of data from a well controlled biology experiment. This is usually my line of argument when students ask about the suitability of a topic for an EE in biology. In the case above I asked, "what is it about eating just McDo which is going to make you feel bad (or good?)" and "can you think of a way to test that idea which will give you enough reliable data to draw a conclusion?". We narrowed the topic down together.

In the end the student seemed happy to explore the types of fats in the food we eat and their digestion by emulsification using bile and their breakdown by lipase enzymes . I hope in our next meeting she will still be keen on the topic and we can discuss potential research questions and how we might find answers about them using an experiment for which we have plenty of the right equipment.