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
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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
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1
0
Jess Tucker
01/12/2025
Biology
B1 - cells
146
•
1 Dec 2025
•
Jess Tucker
@jesstucker28
Understanding how cells work, divide, and transport materials is fundamental... Show more
Every cell in your body started as a basic unit but developed special features to do specific jobs - this is called cell differentiation. Nerve cells grow long axons to carry electrical signals across your body, whilst muscle cells pack in protein filaments for contraction and movement.
Animal cells contain several key structures you need to know. The nucleus controls everything and contains DNA, whilst mitochondria release energy through respiration. The cell membrane acts like a bouncer, controlling what enters and leaves the cell, and cytoplasm is where most chemical reactions happen.
Plant cells have everything animal cells do, plus some extras. The cell wall made of cellulose provides strength, chloroplasts containing chlorophyll carry out photosynthesis, and a large vacuole keeps the cell rigid with cell sap.
Remember: Use the formula magnification = image size ÷ actual size when calculating microscope work!
The main difference between eukaryotes (animal and plant cells) and prokaryotes (bacteria) is that bacteria have free-flowing DNA and no proper nucleus or mitochondria.
Your body constantly grows and repairs itself through mitosis - a type of cell division that creates identical copies. The cell cycle has three main stages: growth (where the cell gets bigger and DNA copies itself), mitosis (where chromosomes split apart), and finally the cell splits into two identical daughter cells.
Chromosomes are basically long, coiled strands of DNA that come in pairs. Humans have 23 pairs (46 total) in every body cell, and they contain thousands of genes that determine your characteristics.
Stem cells are the ultimate multi-tool of biology - they haven't specialised yet so can become any type of cell your body needs. Embryonic stem cells from very early embryos are the most flexible and show promise for treating conditions like diabetes and paralysis.
Key Point: Adult stem cells are more limited - bone marrow stem cells only make blood cells, brain stem cells only make brain tissue.
Plant stem cells called meristem cells work similarly and can help create disease-resistant crops or save endangered plant species. Understanding stem cells is crucial for modern medical treatments and agricultural advances.
Cells constantly move materials in and out through three main processes. Diffusion is the simplest - particles naturally spread from areas of high concentration to low concentration, like perfume spreading across a room.
Osmosis specifically deals with water movement across partially permeable membranes. Water always moves towards areas with more dissolved substances (higher concentration). This explains why plant cells stay rigid and why putting salt on slugs isn't very kind!
Sometimes cells need to work against the natural flow, which requires active transport. This process uses energy from respiration to move substances from low to high concentration - like pushing water uphill.
Exam Tip: In the potato practical, if the mass increases, water moved in by osmosis. If it decreases, water moved out!
Several features speed up these transport processes. Large surface areas (like root hairs or lung alveoli), thin membranes, short diffusion pathways, and good blood supplies all make transport more efficient. Plants use root hairs for maximum soil contact, whilst your lungs have millions of tiny alveoli for gas exchange.
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.
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
Jess Tucker
@jesstucker28
Understanding how cells work, divide, and transport materials is fundamental to biology. These processes explain everything from how your body grows and repairs itself to how plants absorb nutrients from soil.
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Every cell in your body started as a basic unit but developed special features to do specific jobs - this is called cell differentiation. Nerve cells grow long axons to carry electrical signals across your body, whilst muscle cells pack in protein filaments for contraction and movement.
Animal cells contain several key structures you need to know. The nucleus controls everything and contains DNA, whilst mitochondria release energy through respiration. The cell membrane acts like a bouncer, controlling what enters and leaves the cell, and cytoplasm is where most chemical reactions happen.
Plant cells have everything animal cells do, plus some extras. The cell wall made of cellulose provides strength, chloroplasts containing chlorophyll carry out photosynthesis, and a large vacuole keeps the cell rigid with cell sap.
Remember: Use the formula magnification = image size ÷ actual size when calculating microscope work!
The main difference between eukaryotes (animal and plant cells) and prokaryotes (bacteria) is that bacteria have free-flowing DNA and no proper nucleus or mitochondria.
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your body constantly grows and repairs itself through mitosis - a type of cell division that creates identical copies. The cell cycle has three main stages: growth (where the cell gets bigger and DNA copies itself), mitosis (where chromosomes split apart), and finally the cell splits into two identical daughter cells.
Chromosomes are basically long, coiled strands of DNA that come in pairs. Humans have 23 pairs (46 total) in every body cell, and they contain thousands of genes that determine your characteristics.
Stem cells are the ultimate multi-tool of biology - they haven't specialised yet so can become any type of cell your body needs. Embryonic stem cells from very early embryos are the most flexible and show promise for treating conditions like diabetes and paralysis.
Key Point: Adult stem cells are more limited - bone marrow stem cells only make blood cells, brain stem cells only make brain tissue.
Plant stem cells called meristem cells work similarly and can help create disease-resistant crops or save endangered plant species. Understanding stem cells is crucial for modern medical treatments and agricultural advances.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cells constantly move materials in and out through three main processes. Diffusion is the simplest - particles naturally spread from areas of high concentration to low concentration, like perfume spreading across a room.
Osmosis specifically deals with water movement across partially permeable membranes. Water always moves towards areas with more dissolved substances (higher concentration). This explains why plant cells stay rigid and why putting salt on slugs isn't very kind!
Sometimes cells need to work against the natural flow, which requires active transport. This process uses energy from respiration to move substances from low to high concentration - like pushing water uphill.
Exam Tip: In the potato practical, if the mass increases, water moved in by osmosis. If it decreases, water moved out!
Several features speed up these transport processes. Large surface areas (like root hairs or lung alveoli), thin membranes, short diffusion pathways, and good blood supplies all make transport more efficient. Plants use root hairs for maximum soil contact, whilst your lungs have millions of tiny alveoli for gas exchange.
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.
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Explore the stages of mitosis in detail, including interphase, prophase, metaphase, anaphase, and telophase. This concise summary highlights the key processes involved in cell division, essential for GCSE Edexcel and AQA students. Understand how mitosis contributes to growth and cell replacement, and use the PMAT acronym to remember the sequence of events.
BiologyExplore the processes of cell differentiation, the cell cycle, mitosis, and meiosis. Understand the roles of stem cells, their potency, and the significance of specialized cells like erythrocytes and neutrophils. This summary also addresses ethical concerns surrounding stem cell use and highlights the organization of cells into tissues and organs.
BiologyExplore the essential processes of photosynthesis, including the role of chlorophyll, light-dependent reactions, and factors affecting plant growth. This summary covers the conversion of carbon dioxide and water into glucose, the importance of light, and adaptations of leaves for optimal photosynthesis. Ideal for GCSE Biology students seeking to understand plant productivity and the significance of photosynthesis in ecosystems.
BiologyExplore the key concepts of cell division, including mitosis and meiosis, alongside biological classification methods such as phylogeny and species classification. This summary provides a clear overview of the processes involved in cell division and the importance of classifying organisms based on observable characteristics and genetic relationships. Ideal for GCSE Biology students.
BiologyExplore the detailed stages of mitosis, including Prophase, Metaphase, Anaphase, and Telophase. This summary highlights key events such as chromatin condensation, spindle apparatus formation, and cytokinesis, essential for A Level Biology students. Understand the cell cycle phases and their significance in cell division.
BiologyExplore essential concepts for Biology Paper 1, including eukaryotic and prokaryotic cell structures, mitosis, enzyme functions, and the human circulatory and digestive systems. This comprehensive summary is perfect for exam preparation and understanding key biological processes.
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