Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Biology
9 Dec 2025
306
5 pages
Sam Turnbull @samturnbull
This comprehensive AQA GCSE Biology guide covers all the essential topics you'll need to master for your exams.... Show more
Ever wondered what makes you tick at the most basic level? Cell biology is where it all starts, and it's honestly not as complicated as it sounds.
Animal cells contain five key components nucleus (the control centre), cytoplasm (where reactions happen), cell membrane (the bouncer), mitochondria (powerhouses), and ribosomes (protein factories). Plant cells have all of these plus three extras chloroplasts for photosynthesis, a tough cell wall, and a permanent vacuole for storage.
When it comes to microscopy, remember that light microscopes let you see living cells but with lower resolution, whilst electron microscopes give you incredible detail but can't show living specimens. The magnification formula is dead simple Image size ÷ Actual size = Magnification.
Quick Memory Trick Think of mitosis as "mighty growth" - it's all about growth and repair through cell division!
Your heart works harder than you probably realise, pumping blood through two separate circuits in what's called a double circulatory system. The pulmonary circuit sends blood to your lungs, whilst the systemic circuit delivers oxygen around your body.
Blood vessels each have specific jobs arteries carry blood away from the heart under high pressure (thick walls needed!), veins bring blood back with valves to prevent backflow, and capillaries have ultra-thin walls perfect for exchanging materials.
Pathogens come in four main types bacteria, viruses, fungi, and protists. Your immune system fights back using white blood cells that either engulf invaders (phagocytosis), produce specific antibodies, or release antitoxins. Vaccination works by introducing dead or inactive pathogens to train your immune system's memory cells.
Remember Antibiotics only work against bacteria - they're completely useless against viral infections like the common cold!
Plants are basically living solar panels, converting sunlight into glucose through photosynthesis. The equation might look scary, but it's just carbon dioxide + water + light energy → glucose + oxygen.
Three main factors can limit photosynthesis light intensity, CO₂ concentration, and temperature. Plants need all three in the right amounts to photosynthesise efficiently.
Respiration happens in two flavours. Aerobic respiration uses oxygen to break down glucose completely, producing loads of energy (ATP). Anaerobic respiration kicks in when oxygen runs low - it's much less efficient and produces lactic acid, which is why your muscles ache after intense exercise.
Key Insight Photosynthesis stores energy in glucose, whilst respiration releases that energy for the organism to use - they're essentially opposite processes!
Your body is constantly working to maintain homeostasis - keeping everything stable inside whilst the outside world changes. Think of it as your body's internal thermostat and control system rolled into one.
The nervous system follows a simple pathway stimulus → receptor → coordinator → effector → response. Reflex arcs are your body's emergency shortcuts that bypass the brain for lightning-fast protective responses.
Hormones are chemical messengers produced by glands. Insulin lowers blood glucose when it's too high, whilst glucagon raises it when it's too low. The menstrual cycle involves four key hormones FSH, LH, oestrogen, and progesterone, each playing specific roles in reproduction.
Memory Tip "Insulin IN" - insulin brings glucose levels down by helping cells take it in!
DNA forms a double helix with bases that pair up specifically A with T, and C with G. Understanding inheritance means mastering Punnett squares to predict genetic outcomes from parent combinations.
Sexual reproduction creates genetic variation through meiosis, whilst asexual reproduction produces identical clones through mitosis. This variation is crucial for natural selection - Darwin's idea that organisms with advantageous traits survive and reproduce more successfully.
Ecosystems contain both biotic (living) and abiotic factors. The carbon cycle shows how carbon moves through the atmosphere via respiration, photosynthesis, combustion, and decomposition. Human activities like deforestation and burning fossil fuels disrupt this balance, contributing to global warming.
Exam Success Formula Always use precise scientific terminology and structure longer answers using PEEL - Point, Explain, Example, Link!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
revision notes on all of B6~ inheritance, variation & evolution
BiologyExplore the intricacies of human and plant reproduction in this comprehensive summary. Key topics include the male and female reproductive systems, fertilization processes, the menstrual cycle, DNA inheritance, and the differences between asexual and sexual reproduction. Ideal for GCSE Biology students seeking to understand reproductive mechanisms and genetic principles.
BiologyComprehensive checklist covering all key topics in Edexcel GCSE (9-1) Combined Science, including biology, chemistry, and physics. This resource is designed to aid students in their revision by providing a structured outline of essential concepts such as hormonal control, energy transfers, and the periodic table. Ideal for exam preparation and understanding core scientific principles.
BiologyExplore key concepts in AQA Biology Paper 2, including genetic engineering, diabetes, ecosystems, homeostasis, and evolution. This summary covers essential topics such as the carbon and water cycles, hormonal regulation, and the impact of human activities on biodiversity. Ideal for students preparing for their exams, this resource provides a concise review of critical biological principles and processes.
BiologyExplore the key differences between asexual and sexual reproduction, including advantages and disadvantages of each method. This summary covers essential concepts such as genetic variation, reproduction processes in plants and animals, and examples of organisms that utilize both strategies. Ideal for biology students seeking to understand reproductive mechanisms.
BiologyExplore comprehensive knowledge organisers for AQA GCSE Biology, covering essential topics such as cell structure, genetics, ecosystems, and human biology. These concise summaries are designed to enhance your understanding and retention of key concepts, making them perfect for revision and exam preparation.
BiologyApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sam Turnbull
@samturnbull
This comprehensive AQA GCSE Biology guide covers all the essential topics you'll need to master for your exams. From understanding how cells work to exploring evolution and ecology, these notes break down complex biological concepts into manageable chunks that actually... Show more
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered what makes you tick at the most basic level? Cell biology is where it all starts, and it's honestly not as complicated as it sounds.
Animal cells contain five key components: nucleus (the control centre), cytoplasm (where reactions happen), cell membrane (the bouncer), mitochondria (powerhouses), and ribosomes (protein factories). Plant cells have all of these plus three extras: chloroplasts for photosynthesis, a tough cell wall, and a permanent vacuole for storage.
When it comes to microscopy, remember that light microscopes let you see living cells but with lower resolution, whilst electron microscopes give you incredible detail but can't show living specimens. The magnification formula is dead simple: Image size ÷ Actual size = Magnification.
Quick Memory Trick: Think of mitosis as "mighty growth" - it's all about growth and repair through cell division!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your heart works harder than you probably realise, pumping blood through two separate circuits in what's called a double circulatory system. The pulmonary circuit sends blood to your lungs, whilst the systemic circuit delivers oxygen around your body.
Blood vessels each have specific jobs: arteries carry blood away from the heart under high pressure (thick walls needed!), veins bring blood back with valves to prevent backflow, and capillaries have ultra-thin walls perfect for exchanging materials.
Pathogens come in four main types: bacteria, viruses, fungi, and protists. Your immune system fights back using white blood cells that either engulf invaders (phagocytosis), produce specific antibodies, or release antitoxins. Vaccination works by introducing dead or inactive pathogens to train your immune system's memory cells.
Remember: Antibiotics only work against bacteria - they're completely useless against viral infections like the common cold!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Plants are basically living solar panels, converting sunlight into glucose through photosynthesis. The equation might look scary, but it's just: carbon dioxide + water + light energy → glucose + oxygen.
Three main factors can limit photosynthesis: light intensity, CO₂ concentration, and temperature. Plants need all three in the right amounts to photosynthesise efficiently.
Respiration happens in two flavours. Aerobic respiration uses oxygen to break down glucose completely, producing loads of energy (ATP). Anaerobic respiration kicks in when oxygen runs low - it's much less efficient and produces lactic acid, which is why your muscles ache after intense exercise.
Key Insight: Photosynthesis stores energy in glucose, whilst respiration releases that energy for the organism to use - they're essentially opposite processes!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your body is constantly working to maintain homeostasis - keeping everything stable inside whilst the outside world changes. Think of it as your body's internal thermostat and control system rolled into one.
The nervous system follows a simple pathway: stimulus → receptor → coordinator → effector → response. Reflex arcs are your body's emergency shortcuts that bypass the brain for lightning-fast protective responses.
Hormones are chemical messengers produced by glands. Insulin lowers blood glucose when it's too high, whilst glucagon raises it when it's too low. The menstrual cycle involves four key hormones: FSH, LH, oestrogen, and progesterone, each playing specific roles in reproduction.
Memory Tip: "Insulin IN" - insulin brings glucose levels down by helping cells take it in!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
DNA forms a double helix with bases that pair up specifically: A with T, and C with G. Understanding inheritance means mastering Punnett squares to predict genetic outcomes from parent combinations.
Sexual reproduction creates genetic variation through meiosis, whilst asexual reproduction produces identical clones through mitosis. This variation is crucial for natural selection - Darwin's idea that organisms with advantageous traits survive and reproduce more successfully.
Ecosystems contain both biotic (living) and abiotic factors. The carbon cycle shows how carbon moves through the atmosphere via respiration, photosynthesis, combustion, and decomposition. Human activities like deforestation and burning fossil fuels disrupt this balance, contributing to global warming.
Exam Success Formula: Always use precise scientific terminology and structure longer answers using PEEL - Point, Explain, Example, Link!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
revision notes on all of B6~ inheritance, variation & evolution
BiologyExplore the intricacies of human and plant reproduction in this comprehensive summary. Key topics include the male and female reproductive systems, fertilization processes, the menstrual cycle, DNA inheritance, and the differences between asexual and sexual reproduction. Ideal for GCSE Biology students seeking to understand reproductive mechanisms and genetic principles.
BiologyComprehensive checklist covering all key topics in Edexcel GCSE (9-1) Combined Science, including biology, chemistry, and physics. This resource is designed to aid students in their revision by providing a structured outline of essential concepts such as hormonal control, energy transfers, and the periodic table. Ideal for exam preparation and understanding core scientific principles.
BiologyExplore key concepts in AQA Biology Paper 2, including genetic engineering, diabetes, ecosystems, homeostasis, and evolution. This summary covers essential topics such as the carbon and water cycles, hormonal regulation, and the impact of human activities on biodiversity. Ideal for students preparing for their exams, this resource provides a concise review of critical biological principles and processes.
BiologyExplore the key differences between asexual and sexual reproduction, including advantages and disadvantages of each method. This summary covers essential concepts such as genetic variation, reproduction processes in plants and animals, and examples of organisms that utilize both strategies. Ideal for biology students seeking to understand reproductive mechanisms.
BiologyExplore comprehensive knowledge organisers for AQA GCSE Biology, covering essential topics such as cell structure, genetics, ecosystems, and human biology. These concise summaries are designed to enhance your understanding and retention of key concepts, making them perfect for revision and exam preparation.
BiologyApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology