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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Biology
3 Dec 2025
86
2 pages
Your body is made up of millions of specialised cells, each with a unique job to do. Understanding... Show more
Most animal cells don't stay as basic, all-purpose cells - they become specialised through a process called differentiation. This is like having different workers with specific skills rather than everyone doing the same job.
Sperm cells are brilliant examples of specialisation because they're built for one mission reaching and fertilising an egg cell (ovum). They carry the male's genetic information in their nucleus, but only half the DNA that normal adult cells contain.
These cells are perfectly designed for their journey. Their streamlined shape and long tail help them swim efficiently towards the egg. They're also packed with mitochondria to provide the energy needed for all that swimming.
Key fact Sperm cells contain special enzymes that literally digest through the outer layer of the egg - like having a biological drill to break through!
Nerve cells are your body's electrical messaging system, sending impulses at incredible speeds. The axon acts like a biological wire, carrying electrical signals from one part of your body to another.
What makes nerve cells so efficient? The myelin coating insulates the axon and speeds up signal transmission - imagine it as the plastic coating on electrical wires. Dendrites increase the surface area, making it easier for other nerve cells to connect, whilst synapses are the junction points where signals jump between cells.
Muscle cells have a completely different job - they need to contract and create movement. These cells are stuffed with mitochondria for energy and contain special protein fibres that can change length.
Remember this When muscle cells contract, the protein fibres shorten, which decreases the cell's length and creates the pulling force that moves your 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 โ all at your fingertips.
2
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the anatomy and physiology of the human heart, including detailed diagrams and notes on blood circulation, heart chambers, valves, and coronary arteries. This summary covers key concepts such as the role of the atria and ventricles, the function of valves, and the importance of coronary arteries in supplying oxygenated blood to the heart muscle. Ideal for biology revision.
BiologyExplore the key concepts of transport in animals, including blood flow, heart structure, and the role of haemoglobin in oxygen dissociation. This comprehensive summary covers the cardiac cycle, blood vessels, and the circulatory system, providing essential insights for OCR A Biology Module 3.1.2.
BiologyExplore the structure and functions of the mammalian heart in this detailed summary. Understand the roles of oxygenated and deoxygenated blood, the heart's chambers, and the circulatory system. Ideal for GCSE Biology students preparing for exams. Includes key concepts such as heart structure, blood circulation, and the role of cardiac muscle.
BiologyExplore the intricate flow of blood through the heart's structures, including the superior vena cava, atria, ventricles, and valves. This summary provides a clear overview of the mammalian heart and its role in blood circulation, ideal for Year 10 students.
BiologyComprehensive overview of transport systems in animals, covering the cardiac cycle, blood circulation, and the role of haemoglobin in oxygen transport. This resource aligns with the EDUQAS A Level Biology specification, focusing on key concepts such as blood components, heart structure, and the lymphatic system. Ideal for revision and exam preparation.
BiologyExplore the anatomy and functions of the heart, including the roles of atria, ventricles, valves, and blood vessels in circulation. This summary covers key concepts such as deoxygenated and oxygenated blood flow, and the heart's role in the circulatory system.
BiologyQuotes from every main character
English LiteratureApp 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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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
Your body is made up of millions of specialised cells, each with a unique job to do. Understanding how these cells are perfectly adapted for their specific functions will help you grasp how your body works as an amazing, coordinated... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Most animal cells don't stay as basic, all-purpose cells - they become specialised through a process called differentiation. This is like having different workers with specific skills rather than everyone doing the same job.
Sperm cells are brilliant examples of specialisation because they're built for one mission: reaching and fertilising an egg cell (ovum). They carry the male's genetic information in their nucleus, but only half the DNA that normal adult cells contain.
These cells are perfectly designed for their journey. Their streamlined shape and long tail help them swim efficiently towards the egg. They're also packed with mitochondria to provide the energy needed for all that swimming.
Key fact: Sperm cells contain special enzymes that literally digest through the outer layer of the egg - like having a biological drill to break through!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Nerve cells are your body's electrical messaging system, sending impulses at incredible speeds. The axon acts like a biological wire, carrying electrical signals from one part of your body to another.
What makes nerve cells so efficient? The myelin coating insulates the axon and speeds up signal transmission - imagine it as the plastic coating on electrical wires. Dendrites increase the surface area, making it easier for other nerve cells to connect, whilst synapses are the junction points where signals jump between cells.
Muscle cells have a completely different job - they need to contract and create movement. These cells are stuffed with mitochondria for energy and contain special protein fibres that can change length.
Remember this: When muscle cells contract, the protein fibres shorten, which decreases the cell's length and creates the pulling force that moves your 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 โ all at your fingertips.
2
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
Explore the anatomy and physiology of the human heart, including detailed diagrams and notes on blood circulation, heart chambers, valves, and coronary arteries. This summary covers key concepts such as the role of the atria and ventricles, the function of valves, and the importance of coronary arteries in supplying oxygenated blood to the heart muscle. Ideal for biology revision.
BiologyExplore the key concepts of transport in animals, including blood flow, heart structure, and the role of haemoglobin in oxygen dissociation. This comprehensive summary covers the cardiac cycle, blood vessels, and the circulatory system, providing essential insights for OCR A Biology Module 3.1.2.
BiologyExplore the structure and functions of the mammalian heart in this detailed summary. Understand the roles of oxygenated and deoxygenated blood, the heart's chambers, and the circulatory system. Ideal for GCSE Biology students preparing for exams. Includes key concepts such as heart structure, blood circulation, and the role of cardiac muscle.
BiologyExplore the intricate flow of blood through the heart's structures, including the superior vena cava, atria, ventricles, and valves. This summary provides a clear overview of the mammalian heart and its role in blood circulation, ideal for Year 10 students.
BiologyComprehensive overview of transport systems in animals, covering the cardiac cycle, blood circulation, and the role of haemoglobin in oxygen transport. This resource aligns with the EDUQAS A Level Biology specification, focusing on key concepts such as blood components, heart structure, and the lymphatic system. Ideal for revision and exam preparation.
BiologyExplore the anatomy and functions of the heart, including the roles of atria, ventricles, valves, and blood vessels in circulation. This summary covers key concepts such as deoxygenated and oxygenated blood flow, and the heart's role in the circulatory system.
BiologyQuotes from every main character
English LiteratureApp 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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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 itโs 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 didnโt even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as Iโm 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 ๐๐๐ฒ๐ค๐โจ๐๐ฎ
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