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
1 Dec 2025
150
4 pages
Faye Findlay @fayefindlay_ylvf
Biology covers key processes that keep living things functioning. From energy production to disease prevention, these concepts help... Show more
Ever wondered how plants make their own food? During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen . This process needs light energy and is affected by the intensity of light - the closer the light source, the more effective the process.
Plants don't waste the glucose they produce. They use it for respiration, building cellulose for cell walls, making amino acids, and storing energy as oils, fats or starch for later use. However, photosynthesis can be limited by factors like light intensity, temperature, CO₂ availability, and amount of chlorophyll.
Respiration is how all living cells release energy from glucose. In aerobic respiration, cells use oxygen to break down glucose completely . This happens in specialized cell structures called mitochondria. When oxygen is limited, cells switch to anaerobic respiration, producing lactic acid instead and releasing less energy.
Did you know? Every cell in your body is constantly performing respiration, even when you're sleeping. This process provides the energy needed for everything from thinking to running.
Your body is constantly under attack from pathogens - microorganisms that cause disease. These come in various forms, each with their own ways of causing harm. Viruses like measles and HIV replicate inside your cells, creating copies that burst out and infect more cells. Bacteria like Salmonella produce toxins that damage tissues, while fungi can penetrate skin causing infections.
Your immune system fights back using white blood cells that consume pathogens, produce antibodies to tag them for destruction, and create antitoxins to neutralize harmful bacterial products. It's like having your own personal army!
Vaccines are one of medicine's greatest tools against disease. They contain dead or weakened pathogens that can't cause illness but still carry the antigens (markers) that trigger your immune system. This gives your body a chance to prepare its defenses before encountering the real pathogen.
Remember this Vaccines don't just protect you - they protect everyone around you by reducing the spread of communicable diseases. This is called herd immunity.
Your body is organized in increasingly complex levels - cells combine to form tissues, tissues form organs, and organs work together in organ systems. This organization allows for specialized functions throughout your body.
The circulatory system demonstrates this perfectly. Your heart pumps oxygenated blood through arteries to body tissues via a double circulatory system. Meanwhile, deoxygenated blood returns through veins to the heart, then travels to the lungs to collect oxygen and remove carbon dioxide.
Digestion shows how different organs work together to process food. Special proteins called enzymes act as biological catalysts in this process. Each enzyme has a specific active site that fits only one substrate (like a lock and key), and they work best at specific temperatures and pH levels. Different enzymes break down specific nutrients - amylase for carbohydrates, proteases for proteins, and lipases for fats.
Fascinating fact Your blood contains different components with specific jobs red blood cells carry oxygen, white blood cells fight infection, platelets help with clotting, and plasma transports everything around your body.
Cells are the building blocks of life, but they're not all the same. Eukaryotic cells (found in animals and plants) have a nucleus and membrane-bound organelles. Plant cells have additional features like chloroplasts for photosynthesis, a rigid cell wall, and a large vacuole. Prokaryotic cells like bacteria are simpler, lacking a true nucleus.
How do cells get what they need? Diffusion is the movement of particles from high to low concentration areas. Osmosis is specifically the movement of water molecules across a partially permeable membrane. When cells need to move substances against concentration gradients, they use active transport, which requires energy.
The cell cycle ensures organisms can grow and repair themselves. During interphase, the cell grows and copies its DNA. This is followed by mitosis (nuclear division) and cytokinesis (cytoplasm division). Stem cells are special cells that can divide to form different cell types - embryonic stem cells can form all cell types, while adult stem cells are more limited.
Quick tip When studying cell structures, remember that form follows function. The structure of each cell type (like sperm, nerve, or muscle cells) is perfectly adapted to its specific job in the body.
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.
4
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
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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
Faye Findlay
@fayefindlay_ylvf
Biology covers key processes that keep living things functioning. From energy production to disease prevention, these concepts help us understand how our bodies work and how organisms interact with their environment. Let's explore these fundamental biological processes that form the... Show more
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Ever wondered how plants make their own food? During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen . This process needs light energy and is affected by the intensity of light - the closer the light source, the more effective the process.
Plants don't waste the glucose they produce. They use it for respiration, building cellulose for cell walls, making amino acids, and storing energy as oils, fats or starch for later use. However, photosynthesis can be limited by factors like light intensity, temperature, CO₂ availability, and amount of chlorophyll.
Respiration is how all living cells release energy from glucose. In aerobic respiration, cells use oxygen to break down glucose completely . This happens in specialized cell structures called mitochondria. When oxygen is limited, cells switch to anaerobic respiration, producing lactic acid instead and releasing less energy.
Did you know? Every cell in your body is constantly performing respiration, even when you're sleeping. This process provides the energy needed for everything from thinking to running.
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 under attack from pathogens - microorganisms that cause disease. These come in various forms, each with their own ways of causing harm. Viruses like measles and HIV replicate inside your cells, creating copies that burst out and infect more cells. Bacteria like Salmonella produce toxins that damage tissues, while fungi can penetrate skin causing infections.
Your immune system fights back using white blood cells that consume pathogens, produce antibodies to tag them for destruction, and create antitoxins to neutralize harmful bacterial products. It's like having your own personal army!
Vaccines are one of medicine's greatest tools against disease. They contain dead or weakened pathogens that can't cause illness but still carry the antigens (markers) that trigger your immune system. This gives your body a chance to prepare its defenses before encountering the real pathogen.
Remember this: Vaccines don't just protect you - they protect everyone around you by reducing the spread of communicable diseases. This is called herd immunity.
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 organized in increasingly complex levels - cells combine to form tissues, tissues form organs, and organs work together in organ systems. This organization allows for specialized functions throughout your body.
The circulatory system demonstrates this perfectly. Your heart pumps oxygenated blood through arteries to body tissues via a double circulatory system. Meanwhile, deoxygenated blood returns through veins to the heart, then travels to the lungs to collect oxygen and remove carbon dioxide.
Digestion shows how different organs work together to process food. Special proteins called enzymes act as biological catalysts in this process. Each enzyme has a specific active site that fits only one substrate (like a lock and key), and they work best at specific temperatures and pH levels. Different enzymes break down specific nutrients - amylase for carbohydrates, proteases for proteins, and lipases for fats.
Fascinating fact: Your blood contains different components with specific jobs: red blood cells carry oxygen, white blood cells fight infection, platelets help with clotting, and plasma transports everything around your body.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cells are the building blocks of life, but they're not all the same. Eukaryotic cells (found in animals and plants) have a nucleus and membrane-bound organelles. Plant cells have additional features like chloroplasts for photosynthesis, a rigid cell wall, and a large vacuole. Prokaryotic cells like bacteria are simpler, lacking a true nucleus.
How do cells get what they need? Diffusion is the movement of particles from high to low concentration areas. Osmosis is specifically the movement of water molecules across a partially permeable membrane. When cells need to move substances against concentration gradients, they use active transport, which requires energy.
The cell cycle ensures organisms can grow and repair themselves. During interphase, the cell grows and copies its DNA. This is followed by mitosis (nuclear division) and cytokinesis (cytoplasm division). Stem cells are special cells that can divide to form different cell types - embryonic stem cells can form all cell types, while adult stem cells are more limited.
Quick tip: When studying cell structures, remember that form follows function. The structure of each cell type (like sperm, nerve, or muscle cells) is perfectly adapted to its specific job in the body.
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.
4
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
App 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