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
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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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0
AbigailTheFish
09/12/2025
Biology
Cellular Respiration
474
•
9 Dec 2025
•
AbigailTheFish
@fishythefish
Your cells are like tiny power stations, constantly converting glucose... Show more
Ever wonder how your body turns that sandwich into actual energy? Cellular respiration is the process where your cells convert glucose into ATP, which is like the batteries that power everything in your body. Most of this energy production happens inside special organelles called mitochondria.
The process kicks off with anaerobic respiration, which doesn't need oxygen and happens in your cell's cytoplasm. During glycolysis, one glucose molecule gets broken down into two smaller molecules called pyruvate, producing a small amount of ATP in the process.
If there's no oxygen around, your cells switch to fermentation to squeeze out a bit more energy. This creates different byproducts depending on the organism - in your muscles, it makes lactic acid (that burning feeling when you exercise hard!), whilst in bacteria and yeast, it produces ethanol.
Quick Fact: The mitochondria has different compartments - the outer membrane, inner membrane, intermembrane space, cristae (fancy folds), and the matrix where the real magic happens!
When oxygen is available, things get much more exciting with aerobic respiration! The pyruvate molecules travel into the mitochondrial matrix and enter the Krebs Cycle, where they get completely broken down and release high-energy electrons.
These electrons can't just float around on their own, so special molecules called electron carriers grab them and transport them to the Electron Transport Chain (ETC). Think of this chain as a conveyor belt made of proteins in the inner membrane of the mitochondria.
As electrons move through this protein chain, they release energy that powers the proteins to pump hydrogen ions from the matrix into the intermembrane space. This creates a massive build-up of hydrogen ions on one side of the membrane, making the mitochondria work like a charged battery.
Amazing Fact: Your mitochondria literally becomes like a biological battery, storing energy by creating a difference in charge across its inner membrane!
Here's where the real energy production happens! All those hydrogen ions crowded in the intermembrane space want to flow back into the matrix because of diffusion - particles naturally move from areas of high concentration to low concentration.
The only way back is through a special protein called ATP Synthase, which works like a revolving door or waterwheel. As hydrogen ions rush through this protein, they cause it to spin, and this spinning motion creates loads of ATP through a process called chemiosmosis.
Meanwhile, oxygen (the reason you breathe!) swoops in to collect all the low-energy electrons that have finished their journey through the transport chain. These electrons combine with hydrogen and oxygen to form water - yes, you're literally making water inside your cells!
This entire final stage is called oxidative phosphorylation, and it's why oxygen is absolutely essential for complex life. Without oxygen, the whole system would get clogged up like a blocked drain, and your cells would stop producing the energy you need to survive.
Mind-blowing Reality: When you exercise and breathe harder, you're not just getting more oxygen for energy - you're also helping your cells clean up all those leftover electrons and hydrogen!
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.
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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
AbigailTheFish
@fishythefish
Your cells are like tiny power stations, constantly converting glucose into ATP- the energy currency that keeps you alive. This amazing process, called cellular respiration, happens in two main stages and is absolutely crucial for everything from thinking to... Show more
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Ever wonder how your body turns that sandwich into actual energy? Cellular respiration is the process where your cells convert glucose into ATP, which is like the batteries that power everything in your body. Most of this energy production happens inside special organelles called mitochondria.
The process kicks off with anaerobic respiration, which doesn't need oxygen and happens in your cell's cytoplasm. During glycolysis, one glucose molecule gets broken down into two smaller molecules called pyruvate, producing a small amount of ATP in the process.
If there's no oxygen around, your cells switch to fermentation to squeeze out a bit more energy. This creates different byproducts depending on the organism - in your muscles, it makes lactic acid (that burning feeling when you exercise hard!), whilst in bacteria and yeast, it produces ethanol.
Quick Fact: The mitochondria has different compartments - the outer membrane, inner membrane, intermembrane space, cristae (fancy folds), and the matrix where the real magic happens!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When oxygen is available, things get much more exciting with aerobic respiration! The pyruvate molecules travel into the mitochondrial matrix and enter the Krebs Cycle, where they get completely broken down and release high-energy electrons.
These electrons can't just float around on their own, so special molecules called electron carriers grab them and transport them to the Electron Transport Chain (ETC). Think of this chain as a conveyor belt made of proteins in the inner membrane of the mitochondria.
As electrons move through this protein chain, they release energy that powers the proteins to pump hydrogen ions from the matrix into the intermembrane space. This creates a massive build-up of hydrogen ions on one side of the membrane, making the mitochondria work like a charged battery.
Amazing Fact: Your mitochondria literally becomes like a biological battery, storing energy by creating a difference in charge across its inner membrane!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Here's where the real energy production happens! All those hydrogen ions crowded in the intermembrane space want to flow back into the matrix because of diffusion - particles naturally move from areas of high concentration to low concentration.
The only way back is through a special protein called ATP Synthase, which works like a revolving door or waterwheel. As hydrogen ions rush through this protein, they cause it to spin, and this spinning motion creates loads of ATP through a process called chemiosmosis.
Meanwhile, oxygen (the reason you breathe!) swoops in to collect all the low-energy electrons that have finished their journey through the transport chain. These electrons combine with hydrogen and oxygen to form water - yes, you're literally making water inside your cells!
This entire final stage is called oxidative phosphorylation, and it's why oxygen is absolutely essential for complex life. Without oxygen, the whole system would get clogged up like a blocked drain, and your cells would stop producing the energy you need to survive.
Mind-blowing Reality: When you exercise and breathe harder, you're not just getting more oxygen for energy - you're also helping your cells clean up all those leftover electrons and hydrogen!
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 essential processes of aerobic respiration, including the chemical equation, the role of oxygen, and the significance of by-products like carbon dioxide and water. This summary covers key concepts such as cellular bioenergetics and the differences between respiration and breathing, making it ideal for GCSE Biology students.
BiologyExplore the mechanisms of gas exchange in humans and plants, including the role of alveoli and spongy mesophyll. Understand aerobic and anaerobic respiration processes, their equations, and practical experiments. This summary is essential for CCEA GCSE Biology students focusing on cellular energetics and respiratory systems.
BiologyExplore the process of aerobic respiration in mitochondria, including ATP production, energy transfer, and the role of glucose in cellular activities. This summary covers key concepts such as muscle cell energy requirements, glycolysis, and fermentation, making it essential for Nat 5 Biology students.
BiologyExplore the processes of aerobic and anaerobic respiration, including energy production, the role of enzymes, and the impact of exercise on muscle function. This summary covers key concepts such as ATP production, glucose breakdown, and the physiological changes during physical activity. Ideal for students studying biology and cellular metabolism.
BiologyExplore the physiological effects of exercise on respiration, including aerobic and anaerobic processes, oxygen debt, and muscle fatigue. This summary covers key concepts such as energy demands during physical activity, the role of lactic acid, and the importance of respiration in cellular metabolism. Ideal for AQA GCSE Biology students.
BiologyExplore the essential processes of cellular respiration, including aerobic and anaerobic pathways, ATP production, and fermentation. This summary covers key concepts such as respiratory substrates, oxidation, and energy transfer, tailored for GCSE OCR Biology students.
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