Subjects
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
8 Dec 2025
185
6 pages
evie @e777
Biology is all about understanding how life works, from the tiniest cells in your body to entire ecosystems.... Show more
Think of biology as the ultimate instruction manual for life itself. Every living thing follows the same basic rules, whether it's a bacterium or a blue whale.
Your body is like a perfectly organised factory with different levels of complexity. Cells are the smallest living units - imagine them as tiny workers doing specific jobs.
When similar cells team up, they form tissues (like muscle tissue). Different tissues combine to create organs (like your heart), and organs work together in organ systems (like your circulatory system). Finally, all these systems make up an organism - you!
Key tip Remember the order from smallest to largest Cell → Tissue → Organ → Organ System → Organism. This hierarchy appears in loads of exam questions!
Two massive chemical reactions keep life ticking along, and they're basically opposites of each other. Respiration happens inside your cells right now, releasing energy from glucose so you can move, think, and stay alive.
Aerobic respiration uses oxygen and creates carbon dioxide and water as waste products. When you're exercising hard and run out of oxygen, anaerobic respiration kicks in, producing lactic acid (that burning feeling in your muscles).
Photosynthesis is what plants do to make their own food using sunlight. It's the reverse of respiration - plants take in carbon dioxide and water to produce glucose and oxygen.
Remember this Respiration releases energy, photosynthesis stores energy. They're like opposite sides of the same coin!
Scientists love organising things, and the Linnaean system is how they sort all living things into groups. Think of it like a filing system that gets more specific as you go down.
It starts broad with Kingdom (like animals or plants), then narrows down through Phylum, Class, Order, Family, and Genus until you reach Species - the most specific group.
Here's a memory trick "King Philip Came Over For Good Soup" helps you remember the order from largest to smallest group.
Exam hack You're likely to get questions asking you to put these categories in order, so practise this sequence until it's automatic!
Your digestive system is basically a 9-metre-long tube that breaks down food and absorbs nutrients. Food travels from your mouth down the oesophagus into your stomach, where acid begins breaking it down.
The liver and pancreas are your chemical factories, producing enzymes and bile to help digest fats and proteins. The gallbladder stores bile until it's needed.
Most nutrient absorption happens in your small intestine, whilst the large intestine removes water and forms waste. The journey ends at the rectum where waste exits your body.
Visual learner? Try tracing the path of a sandwich through your digestive system - it makes the whole process much clearer!
Microscopes are your window into the invisible world of cells. The eyepiece lens is where you look, whilst objective lenses on the nose piece provide different magnification levels.
The stage holds your specimen in place with clips, and the mirror reflects light up through your sample. Getting a clear image is all about the focus controls.
Use coarse focus first to get roughly the right distance, then switch to fine focus for crystal-clear images. Start with the lowest magnification and work your way up.
Lab success tip Always start with the lowest power objective lens - it's much easier to find your specimen this way, and you're less likely to damage the slide!
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the fundamental concepts of chemical bonding, including metallic bonding, covalent structures, and the role of delocalized electrons. This summary covers key properties of metals, alloys, and carbon-based structures like graphene and carbon nanotubes, providing a comprehensive overview for chemistry students. Ideal for exam preparation and quick reference.
BiologyExplore essential microscopy techniques, including slide preparation, staining methods, and the development of cell theory. This summary covers key historical milestones, types of microscopes, and practical applications in biology, making it ideal for A Level Biology students. Understand how to differentiate between cell types and the significance of staining in microscopy.
BiologyExplore the various types of microscopes including Optical, Transmission Electron Microscopes (TEMs), and Scanning Electron Microscopes (SEMs). This summary covers key concepts such as magnification, resolution, and the advantages and disadvantages of each microscope type. Ideal for A-level biology students studying cell structure and microscopy techniques.
BiologyMaster the essential steps for using a microscope effectively in Year 7 science. This guide covers key components such as the ocular lens, objective lenses, and stage controls, along with detailed instructions for focusing and magnification adjustments. Ideal for students preparing for exams or practical assessments.
BiologyExplore the intricate structures and functions of eukaryotic cells, including organelles like the nucleus, mitochondria, and chloroplasts. This summary covers key concepts in cellular biology, microscopy techniques, and the differences between prokaryotic and eukaryotic cells. Ideal for students studying cell biology and related fields.
BiologyYr 11 gcse B1 revision OCR exam board
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
evie
@e777
Biology is all about understanding how life works, from the tiniest cells in your body to entire ecosystems. This summary covers the fundamental concepts you'll need to master - from how your body is organised to the chemical reactions keeping... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think of biology as the ultimate instruction manual for life itself. Every living thing follows the same basic rules, whether it's a bacterium or a blue whale.
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 like a perfectly organised factory with different levels of complexity. Cells are the smallest living units - imagine them as tiny workers doing specific jobs.
When similar cells team up, they form tissues (like muscle tissue). Different tissues combine to create organs (like your heart), and organs work together in organ systems (like your circulatory system). Finally, all these systems make up an organism - you!
Key tip: Remember the order from smallest to largest: Cell → Tissue → Organ → Organ System → Organism. This hierarchy appears in loads of exam questions!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Two massive chemical reactions keep life ticking along, and they're basically opposites of each other. Respiration happens inside your cells right now, releasing energy from glucose so you can move, think, and stay alive.
Aerobic respiration uses oxygen and creates carbon dioxide and water as waste products. When you're exercising hard and run out of oxygen, anaerobic respiration kicks in, producing lactic acid (that burning feeling in your muscles).
Photosynthesis is what plants do to make their own food using sunlight. It's the reverse of respiration - plants take in carbon dioxide and water to produce glucose and oxygen.
Remember this: Respiration releases energy, photosynthesis stores energy. They're like opposite sides of the same coin!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Scientists love organising things, and the Linnaean system is how they sort all living things into groups. Think of it like a filing system that gets more specific as you go down.
It starts broad with Kingdom (like animals or plants), then narrows down through Phylum, Class, Order, Family, and Genus until you reach Species - the most specific group.
Here's a memory trick: "King Philip Came Over For Good Soup" helps you remember the order from largest to smallest group.
Exam hack: You're likely to get questions asking you to put these categories in order, so practise this sequence until it's automatic!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your digestive system is basically a 9-metre-long tube that breaks down food and absorbs nutrients. Food travels from your mouth down the oesophagus into your stomach, where acid begins breaking it down.
The liver and pancreas are your chemical factories, producing enzymes and bile to help digest fats and proteins. The gallbladder stores bile until it's needed.
Most nutrient absorption happens in your small intestine, whilst the large intestine removes water and forms waste. The journey ends at the rectum where waste exits your body.
Visual learner? Try tracing the path of a sandwich through your digestive system - it makes the whole process much clearer!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Microscopes are your window into the invisible world of cells. The eyepiece lens is where you look, whilst objective lenses on the nose piece provide different magnification levels.
The stage holds your specimen in place with clips, and the mirror reflects light up through your sample. Getting a clear image is all about the focus controls.
Use coarse focus first to get roughly the right distance, then switch to fine focus for crystal-clear images. Start with the lowest magnification and work your way up.
Lab success tip: Always start with the lowest power objective lens - it's much easier to find your specimen this way, and you're less likely to damage the slide!
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the fundamental concepts of chemical bonding, including metallic bonding, covalent structures, and the role of delocalized electrons. This summary covers key properties of metals, alloys, and carbon-based structures like graphene and carbon nanotubes, providing a comprehensive overview for chemistry students. Ideal for exam preparation and quick reference.
BiologyExplore essential microscopy techniques, including slide preparation, staining methods, and the development of cell theory. This summary covers key historical milestones, types of microscopes, and practical applications in biology, making it ideal for A Level Biology students. Understand how to differentiate between cell types and the significance of staining in microscopy.
BiologyExplore the various types of microscopes including Optical, Transmission Electron Microscopes (TEMs), and Scanning Electron Microscopes (SEMs). This summary covers key concepts such as magnification, resolution, and the advantages and disadvantages of each microscope type. Ideal for A-level biology students studying cell structure and microscopy techniques.
BiologyMaster the essential steps for using a microscope effectively in Year 7 science. This guide covers key components such as the ocular lens, objective lenses, and stage controls, along with detailed instructions for focusing and magnification adjustments. Ideal for students preparing for exams or practical assessments.
BiologyExplore the intricate structures and functions of eukaryotic cells, including organelles like the nucleus, mitochondria, and chloroplasts. This summary covers key concepts in cellular biology, microscopy techniques, and the differences between prokaryotic and eukaryotic cells. Ideal for students studying cell biology and related fields.
BiologyYr 11 gcse B1 revision OCR exam board
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