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d_bhagi
29/11/2025
Biology
Cellular Respiration
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29 Nov 2025
•
Understanding Cellular Respiration in Biology
D
d_bhagi
@d_bhagi_yjco
1 / 3
Getting Started: Glycolysis
Your cells are basically energy factories, and cellular respiration is their main production line. The whole process happens in three key stages: glycolysis in your cell's cytoplasm, the citric acid cycle in your mitochondria's matrix, and the electron transport chain on the inner mitochondrial membrane.
Glycolysis kicks things off by breaking down glucose into two pyruvate molecules - and here's the clever bit, it doesn't even need oxygen to work. Think of it like an investment where you spend money to make more money.
Your cell first invests 2 ATP molecules to get the glucose ready (the energy investment phase), then cashes in by producing 4 ATP molecules as glucose breaks down completely. That gives you a neat profit of 2 ATP molecules in the energy pay-off stage.
Quick tip: Remember that dehydrogenase enzymes are constantly removing hydrogen ions and electrons, passing them to NAD to form NADH - this will be crucial later in the process!
Two Paths: Fermentation vs Citric Acid Cycle
Here's where things get interesting - your pyruvate molecules are at a crossroads. If there's plenty of oxygen around (aerobic conditions), they'll head into the citric acid cycle. But if oxygen's running low, they'll take the fermentation route instead.
Fermentation happens right in your cytoplasm and comes in two flavours. In your muscle cells, pyruvate becomes lactate (that's what causes the burn during intense exercise!). In yeast and plants, it produces ethanol and carbon dioxide - which is how we get bread and alcoholic drinks.
When oxygen is available, pyruvate gets converted into an acetyl group that joins with coenzyme A to form acetyl coenzyme A. This is your ticket into the citric acid cycle, where the real ATP production begins.
Remember: The citric acid cycle is like a recycling plant - acetyl coenzyme A combines with oxaloacetate to make citrate, which then gets broken down step by step until it's back to oxaloacetate again, generating ATP and releasing CO₂ along the way.
The Power Plant: Electron Transport Chain
The electron transport chain is where cellular respiration really shows off. Picture a series of carrier proteins on your mitochondria's inner membrane, passing electrons along like a bucket brigade. Each handoff releases energy that pumps hydrogen ions across the membrane.
These hydrogen ions then flow back through ATP synthase (think of it as a biological turbine), and this flow powers the production of ATP. Finally, those hydrogen ions and electrons meet up with oxygen to form water - which is why you need to breathe!
From just one glucose molecule, this entire process cranks out an impressive 38 ATP molecules. That's enough energy to power nerve transmission, muscle contraction, and active transport throughout your body.
Brilliant fact: Your body isn't picky about fuel sources - starch, glycogen, proteins, and fats can all be broken down into intermediates that feed into glycolysis or the citric acid cycle, giving you multiple pathways to make ATP when you need it most.
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Best app on earth! no words because it’s too good
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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
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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.
David K
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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
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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
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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.
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
Understanding Cellular Respiration in Biology
D
d_bhagi
@d_bhagi_yjco
Ever wondered how your body turns that sandwich you had for lunch into usable energy? Cellular respiration is the amazing process that breaks down glucose to power everything from your heartbeat to your thoughts. It's like a cellular power plant... Show more
Getting Started: Glycolysis
Your cells are basically energy factories, and cellular respiration is their main production line. The whole process happens in three key stages: glycolysis in your cell's cytoplasm, the citric acid cycle in your mitochondria's matrix, and the electron transport chain on the inner mitochondrial membrane.
Glycolysis kicks things off by breaking down glucose into two pyruvate molecules - and here's the clever bit, it doesn't even need oxygen to work. Think of it like an investment where you spend money to make more money.
Your cell first invests 2 ATP molecules to get the glucose ready (the energy investment phase), then cashes in by producing 4 ATP molecules as glucose breaks down completely. That gives you a neat profit of 2 ATP molecules in the energy pay-off stage.
Quick tip: Remember that dehydrogenase enzymes are constantly removing hydrogen ions and electrons, passing them to NAD to form NADH - this will be crucial later in the process!
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Two Paths: Fermentation vs Citric Acid Cycle
Here's where things get interesting - your pyruvate molecules are at a crossroads. If there's plenty of oxygen around (aerobic conditions), they'll head into the citric acid cycle. But if oxygen's running low, they'll take the fermentation route instead.
Fermentation happens right in your cytoplasm and comes in two flavours. In your muscle cells, pyruvate becomes lactate (that's what causes the burn during intense exercise!). In yeast and plants, it produces ethanol and carbon dioxide - which is how we get bread and alcoholic drinks.
When oxygen is available, pyruvate gets converted into an acetyl group that joins with coenzyme A to form acetyl coenzyme A. This is your ticket into the citric acid cycle, where the real ATP production begins.
Remember: The citric acid cycle is like a recycling plant - acetyl coenzyme A combines with oxaloacetate to make citrate, which then gets broken down step by step until it's back to oxaloacetate again, generating ATP and releasing CO₂ along the way.
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The Power Plant: Electron Transport Chain
The electron transport chain is where cellular respiration really shows off. Picture a series of carrier proteins on your mitochondria's inner membrane, passing electrons along like a bucket brigade. Each handoff releases energy that pumps hydrogen ions across the membrane.
These hydrogen ions then flow back through ATP synthase (think of it as a biological turbine), and this flow powers the production of ATP. Finally, those hydrogen ions and electrons meet up with oxygen to form water - which is why you need to breathe!
From just one glucose molecule, this entire process cranks out an impressive 38 ATP molecules. That's enough energy to power nerve transmission, muscle contraction, and active transport throughout your body.
Brilliant fact: Your body isn't picky about fuel sources - starch, glycogen, proteins, and fats can all be broken down into intermediates that feed into glycolysis or the citric acid cycle, giving you multiple pathways to make ATP when you need it most.
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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