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20 Dec 2025
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Comprehensive Notes on Respiration in Biology
Los
@los
1 / 5
Respiration and Aerobic Respiration
Think of respiration as your body's power station - it's the process that transfers energy from glucose in every single cell. Without it, you literally couldn't survive for seconds.
Aerobic respiration is the VIP version because it uses oxygen and happens mainly in the mitochondria (your cell's powerhouses). The equation is dead simple: glucose + oxygen → carbon dioxide + water. It's exothermic, meaning it releases energy that powers everything from muscle contractions to keeping your body temperature steady.
Your body uses this transferred energy for three main jobs: building bigger molecules from smaller ones (like making proteins), allowing muscles to contract so you can move, and maintaining your body temperature. Enzymes control every single reaction, acting like molecular managers that keep everything running smoothly.
Quick Tip: Remember that aerobic respiration is the most efficient way to get energy from glucose - think of it as the premium fuel your body prefers.
Anaerobic Respiration and Oxygen Debt
When you're sprinting or doing intense exercise, your body can't deliver oxygen fast enough to your muscles. That's when anaerobic respiration kicks in as an emergency backup system.
In your muscles, glucose breaks down without oxygen to make lactic acid. It's much less efficient than aerobic respiration because glucose isn't fully broken down, but it keeps your muscles working when oxygen runs short. The downside? Lactic acid buildup makes your muscles feel like they're on fire.
After intense exercise, you'll have an oxygen debt - basically, your body owes itself oxygen. That's why you keep breathing hard after stopping exercise. Your body needs this extra oxygen to convert the nasty lactic acid back into harmless carbon dioxide and water.
Your liver also helps out by converting lactic acid back to glucose. Meanwhile, fermentation in yeast cells works similarly, producing ethanol and carbon dioxide - which is why bread rises and alcoholic drinks exist!
Remember: Anaerobic respiration is your body's emergency generator - useful in a crisis but not sustainable long-term.
Exercise and Energy Demands
During exercise, your muscle cells work overtime and need way more energy than usual. Your body responds like a well-oiled machine - breathing rate and heart rate both increase to deliver more oxygen and glucose whilst removing carbon dioxide faster.
When you do vigorous exercise like sprinting, your body simply can't supply oxygen quickly enough. Your muscles switch to anaerobic respiration, but this creates lactic acid buildup that causes pain and muscle fatigue. Your muscles literally get tired and stop working efficiently.
The recovery period after exercise is when your body pays back the oxygen debt. Your heart rate and breathing stay elevated until all that lactic acid is sorted out. This is completely normal and shows your body is working properly to restore balance.
Fun Fact: Your heart rate increases with exercise intensity because your muscles are basically screaming "We need more fuel and oxygen, NOW!"
Investigating Exercise Effects and Metabolism Basics
You can easily measure how exercise affects your body by taking your pulse after different activities - sitting, gentle walking, jogging, and running. Plot these on a bar chart and you'll see your heart rate climbing with exercise intensity.
Metabolism is the sum of all chemical reactions happening in your cells and body. It's like having thousands of tiny factories running simultaneously, all controlled by enzymes. These reactions link together in chains, with one reaction's product becoming the next reaction's starting material.
Some reactions are endothermic and build bigger molecules from smaller ones. Your body makes starch, glycogen, and cellulose from glucose molecules, creates lipids from glycerol and fatty acids, and combines glucose with nitrates to make amino acids for proteins.
Other reactions are exothermic and break large molecules down. Respiration breaks down glucose to power everything, whilst excess protein gets broken down to make urea that you excrete in urine.
Key Point: Metabolism never stops - even when you're sleeping, thousands of chemical reactions keep you alive.
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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.
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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
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
Comprehensive Notes on Respiration in Biology
Los
@los
Your body is like a 24/7 chemical factory, constantly transferring energy and breaking down molecules to keep you alive. Respiration is the star process that powers everything your cells do, from building muscles to keeping your heart beating.
Respiration and Aerobic Respiration
Think of respiration as your body's power station - it's the process that transfers energy from glucose in every single cell. Without it, you literally couldn't survive for seconds.
Aerobic respiration is the VIP version because it uses oxygen and happens mainly in the mitochondria (your cell's powerhouses). The equation is dead simple: glucose + oxygen → carbon dioxide + water. It's exothermic, meaning it releases energy that powers everything from muscle contractions to keeping your body temperature steady.
Your body uses this transferred energy for three main jobs: building bigger molecules from smaller ones (like making proteins), allowing muscles to contract so you can move, and maintaining your body temperature. Enzymes control every single reaction, acting like molecular managers that keep everything running smoothly.
Quick Tip: Remember that aerobic respiration is the most efficient way to get energy from glucose - think of it as the premium fuel your body prefers.
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Anaerobic Respiration and Oxygen Debt
When you're sprinting or doing intense exercise, your body can't deliver oxygen fast enough to your muscles. That's when anaerobic respiration kicks in as an emergency backup system.
In your muscles, glucose breaks down without oxygen to make lactic acid. It's much less efficient than aerobic respiration because glucose isn't fully broken down, but it keeps your muscles working when oxygen runs short. The downside? Lactic acid buildup makes your muscles feel like they're on fire.
After intense exercise, you'll have an oxygen debt - basically, your body owes itself oxygen. That's why you keep breathing hard after stopping exercise. Your body needs this extra oxygen to convert the nasty lactic acid back into harmless carbon dioxide and water.
Your liver also helps out by converting lactic acid back to glucose. Meanwhile, fermentation in yeast cells works similarly, producing ethanol and carbon dioxide - which is why bread rises and alcoholic drinks exist!
Remember: Anaerobic respiration is your body's emergency generator - useful in a crisis but not sustainable long-term.
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Exercise and Energy Demands
During exercise, your muscle cells work overtime and need way more energy than usual. Your body responds like a well-oiled machine - breathing rate and heart rate both increase to deliver more oxygen and glucose whilst removing carbon dioxide faster.
When you do vigorous exercise like sprinting, your body simply can't supply oxygen quickly enough. Your muscles switch to anaerobic respiration, but this creates lactic acid buildup that causes pain and muscle fatigue. Your muscles literally get tired and stop working efficiently.
The recovery period after exercise is when your body pays back the oxygen debt. Your heart rate and breathing stay elevated until all that lactic acid is sorted out. This is completely normal and shows your body is working properly to restore balance.
Fun Fact: Your heart rate increases with exercise intensity because your muscles are basically screaming "We need more fuel and oxygen, NOW!"
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Investigating Exercise Effects and Metabolism Basics
You can easily measure how exercise affects your body by taking your pulse after different activities - sitting, gentle walking, jogging, and running. Plot these on a bar chart and you'll see your heart rate climbing with exercise intensity.
Metabolism is the sum of all chemical reactions happening in your cells and body. It's like having thousands of tiny factories running simultaneously, all controlled by enzymes. These reactions link together in chains, with one reaction's product becoming the next reaction's starting material.
Some reactions are endothermic and build bigger molecules from smaller ones. Your body makes starch, glycogen, and cellulose from glucose molecules, creates lipids from glycerol and fatty acids, and combines glucose with nitrates to make amino acids for proteins.
Other reactions are exothermic and break large molecules down. Respiration breaks down glucose to power everything, whilst excess protein gets broken down to make urea that you excrete in urine.
Key Point: Metabolism never stops - even when you're sleeping, thousands of chemical reactions keep you alive.
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Where can I download the Knowunity app?
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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