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6 Dec 2025
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Cellular Respiration Summary for Biology 2.2
M
Molly
@molly_rife
1 / 5
Cellular Respiration Overview and Glycolysis
Cellular respiration involves three key pathways that work together like a factory assembly line: glycolysis, the citric acid cycle, and the electron transport chain. Each stage builds on the previous one to maximise energy production from glucose.
Glycolysis kicks off in the cytoplasm, where glucose gets broken down into two pyruvate molecules. It's a bit like making an investment - you spend 2 ATP molecules upfront during the energy investment phase, but you get 4 ATP back during the energy payoff stage.
This gives you a net gain of 2 ATP molecules per glucose. The process involves phosphorylation (adding phosphate groups) to make glucose unstable, followed by lysis (splitting) and oxidation reactions that generate NADH molecules.
Key Point: Glycolysis happens in the cytoplasm, produces a net 2 ATP, and doesn't need oxygen - making it crucial for both aerobic and anaerobic conditions.
Fermentation and Citric Acid Cycle
When oxygen runs short, fermentation becomes your backup plan. In your muscle cells, pyruvate converts to lactate (causing that burning sensation during intense exercise), whilst in yeast and plants, it becomes ethanol and carbon dioxide.
However, fermentation only produces 2 ATP molecules total - far less efficient than the 38 ATP from complete aerobic respiration. It's like choosing a bicycle over a car for a long journey.
The citric acid cycle operates in the mitochondrial matrix when oxygen is available. Pyruvate first transforms into acetyl CoA, then combines with oxaloacetate to form citrate. Through enzyme-controlled reactions, citrate cycles back to oxaloacetate, generating ATP, NADH, and carbon dioxide.
Remember: The citric acid cycle is like a recycling plant - oxaloacetate gets regenerated to keep the process running continuously.
Electron Transport Chain
The electron transport chain is where cellular respiration reaches its peak efficiency. Located on the inner mitochondrial membrane (cristae), this series of carrier proteins works like a hydroelectric dam.
Electrons from NADH and FADH₂ pass along the chain, releasing energy that pumps hydrogen ions across the membrane. This creates a concentration gradient - imagine water building up behind a dam.
When these hydrogen ions flow back through ATP synthase, they drive ATP production. Oxygen acts as the final electron acceptor, combining with electrons and hydrogen ions to form water.
The electron transport chain produces the most ATP in cellular respiration - about 34 molecules per glucose.
Crucial Concept: Oxygen is essential here as the final electron acceptor. Without it, the entire chain stops, and cells must rely on much less efficient fermentation.
Role of ATP in Cellular Processes
ATP functions as your body's universal energy currency, transferring power to processes that keep you alive and active. Every cellular activity that requires energy depends on ATP breakdown into ADP and phosphate.
Key examples include nerve transmission (sending signals through your nervous system), muscle contraction (enabling movement), and active transport (moving substances against concentration gradients).
The beauty of this system lies in its cycle - ATP breaks down to release energy for cellular work, then gets rebuilt through cellular respiration. It's like having a rechargeable battery that never wears out.
Think of cellular respiration as your body's power grid: glucose and oxygen go in, carbon dioxide and water come out, and ATP provides the energy for everything in between.
Essential Understanding: ATP is the link between energy-releasing processes (like cellular respiration) and energy-requiring processes (like muscle contraction and nerve transmission).
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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.
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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.
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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.
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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
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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
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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
Cellular Respiration Summary for Biology 2.2
M
Molly
@molly_rife
Cellular respiration is your body's way of breaking down glucose to create ATP - the energy currency that powers everything from your heartbeat to your thoughts. Think of it as your cellular power station, running three main processes that transform... Show more
Cellular Respiration Overview and Glycolysis
Cellular respiration involves three key pathways that work together like a factory assembly line: glycolysis, the citric acid cycle, and the electron transport chain. Each stage builds on the previous one to maximise energy production from glucose.
Glycolysis kicks off in the cytoplasm, where glucose gets broken down into two pyruvate molecules. It's a bit like making an investment - you spend 2 ATP molecules upfront during the energy investment phase, but you get 4 ATP back during the energy payoff stage.
This gives you a net gain of 2 ATP molecules per glucose. The process involves phosphorylation (adding phosphate groups) to make glucose unstable, followed by lysis (splitting) and oxidation reactions that generate NADH molecules.
Key Point: Glycolysis happens in the cytoplasm, produces a net 2 ATP, and doesn't need oxygen - making it crucial for both aerobic and anaerobic conditions.
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Fermentation and Citric Acid Cycle
When oxygen runs short, fermentation becomes your backup plan. In your muscle cells, pyruvate converts to lactate (causing that burning sensation during intense exercise), whilst in yeast and plants, it becomes ethanol and carbon dioxide.
However, fermentation only produces 2 ATP molecules total - far less efficient than the 38 ATP from complete aerobic respiration. It's like choosing a bicycle over a car for a long journey.
The citric acid cycle operates in the mitochondrial matrix when oxygen is available. Pyruvate first transforms into acetyl CoA, then combines with oxaloacetate to form citrate. Through enzyme-controlled reactions, citrate cycles back to oxaloacetate, generating ATP, NADH, and carbon dioxide.
Remember: The citric acid cycle is like a recycling plant - oxaloacetate gets regenerated to keep the process running continuously.
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Electron Transport Chain
The electron transport chain is where cellular respiration reaches its peak efficiency. Located on the inner mitochondrial membrane (cristae), this series of carrier proteins works like a hydroelectric dam.
Electrons from NADH and FADH₂ pass along the chain, releasing energy that pumps hydrogen ions across the membrane. This creates a concentration gradient - imagine water building up behind a dam.
When these hydrogen ions flow back through ATP synthase, they drive ATP production. Oxygen acts as the final electron acceptor, combining with electrons and hydrogen ions to form water.
The electron transport chain produces the most ATP in cellular respiration - about 34 molecules per glucose.
Crucial Concept: Oxygen is essential here as the final electron acceptor. Without it, the entire chain stops, and cells must rely on much less efficient fermentation.
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Role of ATP in Cellular Processes
ATP functions as your body's universal energy currency, transferring power to processes that keep you alive and active. Every cellular activity that requires energy depends on ATP breakdown into ADP and phosphate.
Key examples include nerve transmission (sending signals through your nervous system), muscle contraction (enabling movement), and active transport (moving substances against concentration gradients).
The beauty of this system lies in its cycle - ATP breaks down to release energy for cellular work, then gets rebuilt through cellular respiration. It's like having a rechargeable battery that never wears out.
Think of cellular respiration as your body's power grid: glucose and oxygen go in, carbon dioxide and water come out, and ATP provides the energy for everything in between.
Essential Understanding: ATP is the link between energy-releasing processes (like cellular respiration) and energy-requiring processes (like muscle contraction and nerve transmission).
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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