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3 Feb 2026
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Essential Biology Knowledge: Study Guide for Paper 1
H
Haylei-Jai Frost
@hayleijaifrost_sbut
Cell Structure and Functions
Every living thing is made of cells, and each part has a specific job that keeps you alive. The cell membrane acts like a bouncer at a club, controlling what gets in and out. Your nucleus is basically the cell's control centre, telling everything what to do.
The cytoplasm is where most of the action happens - it's like the cell's workspace where chemical reactions take place. Mitochondria are your cell's power stations, releasing energy through respiration so you can actually function.
Plant cells have some extra bits that animal cells don't need. Chloroplasts capture sunlight to make food through photosynthesis, whilst the cell wall gives plants structure (which is why they don't flop about like we would without our skeletons).
Quick Tip: Remember that bacterial cells are much simpler - they don't even have a proper nucleus, just chromosomal DNA floating about with some extra plasmids for bonus features!
Specialised Cells and Microscopes
Your body has different cells designed for specific jobs, and they're all perfectly adapted for what they do. Sperm cells have tails to swim towards eggs, whilst nerve cells are super long to carry electrical signals quickly around your body.
When you want to see cells properly, you'll need a microscope. The key formula to remember is: Magnification = Image size ÷ Actual size. This helps you work out how much bigger something appears compared to real life.
In the lab, you'll slice onions (try not to cry!), add iodine to make structures visible, and use cover slips to get a clear view. Start with low magnification and work your way up - it's much easier to find what you're looking for this way.
Remember: There are five kingdoms of life - plants, animals, fungi, protists, and prokaryotes. Each group has its own special characteristics that help scientists classify living things.
Enzymes and Digestion
Enzymes are like molecular scissors that break down your food into tiny pieces your body can actually use. Each enzyme has a specific active site that only fits one type of substance - think of it like a lock and key system.
Lipase breaks down fats into glycerol and fatty acids, whilst amylase (found in your saliva) starts breaking down starch into glucose before food even reaches your stomach. If enzymes get too hot or the pH changes too much, they denature and stop working completely.
Your liver makes bile which acts like washing-up liquid, breaking large fat droplets into smaller ones so lipase can work more effectively. It's stored in your gall bladder until you need it after a big meal.
Top Tip: Antibiotics only work against bacterial infections, not viruses - that's why doctors won't give them to you for a cold or flu!
Cell Division and Transport
Mitosis creates two identical cells for growth and repair, whilst meiosis makes four genetically different sex cells. The process goes through specific stages: prophase, metaphase, anaphase, and telophase (remember it as "Please Make A Tea").
Substances move around cells in three main ways. Diffusion moves from high to low concentration (like perfume spreading across a room), osmosis specifically moves water molecules, and active transport can move things against the concentration gradient using energy.
Pathogens like bacteria, viruses, fungi, and protists can make you ill, but your immune system fights back. Your skin blocks entry, phagocytes literally eat invaders, and lymphocytes produce specific antibodies to destroy particular pathogens.
Health Focus: Cardiovascular disease is caused by fat building up in blood vessels, often due to smoking, obesity, or stress. Prevention is always better than cure!
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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 Knowunity AI. 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 Knowunity AI. 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
Essential Biology Knowledge: Study Guide for Paper 1
H
Haylei-Jai Frost
@hayleijaifrost_sbut
Biology is absolutely everywhere around you - from the food you digest to the way your muscles move when you text your mates! This covers the essential biology concepts you need to master for your GCSEs, breaking down everything from... Show more
Cell Structure and Functions
Every living thing is made of cells, and each part has a specific job that keeps you alive. The cell membrane acts like a bouncer at a club, controlling what gets in and out. Your nucleus is basically the cell's control centre, telling everything what to do.
The cytoplasm is where most of the action happens - it's like the cell's workspace where chemical reactions take place. Mitochondria are your cell's power stations, releasing energy through respiration so you can actually function.
Plant cells have some extra bits that animal cells don't need. Chloroplasts capture sunlight to make food through photosynthesis, whilst the cell wall gives plants structure (which is why they don't flop about like we would without our skeletons).
Quick Tip: Remember that bacterial cells are much simpler - they don't even have a proper nucleus, just chromosomal DNA floating about with some extra plasmids for bonus features!
Specialised Cells and Microscopes
Your body has different cells designed for specific jobs, and they're all perfectly adapted for what they do. Sperm cells have tails to swim towards eggs, whilst nerve cells are super long to carry electrical signals quickly around your body.
When you want to see cells properly, you'll need a microscope. The key formula to remember is: Magnification = Image size ÷ Actual size. This helps you work out how much bigger something appears compared to real life.
In the lab, you'll slice onions (try not to cry!), add iodine to make structures visible, and use cover slips to get a clear view. Start with low magnification and work your way up - it's much easier to find what you're looking for this way.
Remember: There are five kingdoms of life - plants, animals, fungi, protists, and prokaryotes. Each group has its own special characteristics that help scientists classify living things.
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
Enzymes and Digestion
Enzymes are like molecular scissors that break down your food into tiny pieces your body can actually use. Each enzyme has a specific active site that only fits one type of substance - think of it like a lock and key system.
Lipase breaks down fats into glycerol and fatty acids, whilst amylase (found in your saliva) starts breaking down starch into glucose before food even reaches your stomach. If enzymes get too hot or the pH changes too much, they denature and stop working completely.
Your liver makes bile which acts like washing-up liquid, breaking large fat droplets into smaller ones so lipase can work more effectively. It's stored in your gall bladder until you need it after a big meal.
Top Tip: Antibiotics only work against bacterial infections, not viruses - that's why doctors won't give them to you for a cold or flu!
Cell Division and Transport
Mitosis creates two identical cells for growth and repair, whilst meiosis makes four genetically different sex cells. The process goes through specific stages: prophase, metaphase, anaphase, and telophase (remember it as "Please Make A Tea").
Substances move around cells in three main ways. Diffusion moves from high to low concentration (like perfume spreading across a room), osmosis specifically moves water molecules, and active transport can move things against the concentration gradient using energy.
Pathogens like bacteria, viruses, fungi, and protists can make you ill, but your immune system fights back. Your skin blocks entry, phagocytes literally eat invaders, and lymphocytes produce specific antibodies to destroy particular pathogens.
Health Focus: Cardiovascular disease is caused by fat building up in blood vessels, often due to smoking, obesity, or stress. Prevention is always better than cure!
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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Most popular content: Enzymes
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4.6/5
App Store
4.7/5
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 Knowunity AI. 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 Knowunity AI. 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