This comprehensive AQA GCSE Biology guide covers all the essential... Show more
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30 Dec 2025
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AQA Biology Higher Tier Notes and CheatSheet
S
Sam Turnbull
@samturnbull
1 / 5
Cell Biology and Organisation Fundamentals
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!
Circulatory System and Disease Prevention
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!
Energy Processes: Photosynthesis and Respiration
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!
Homeostasis and Body Control Systems
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!
Genetics, Evolution and Ecology
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!
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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
AQA Biology Higher Tier Notes and CheatSheet
S
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
Cell Biology and Organisation Fundamentals
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!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Circulatory System and Disease Prevention
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!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Energy Processes: Photosynthesis and Respiration
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!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Homeostasis and Body Control Systems
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!
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Genetics, Evolution and Ecology
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!
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Students love us — and so will you.
4.9/5
App Store
4.8/5
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