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leema .
13/12/2025
Biology
bioenergetics, biology
142
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13 Dec 2025
•
Understanding Bioenergetics in Biology
leema .
@leema.x
1 / 4
Photosynthesis - How Plants Make Food
Ever wondered how plants create their own food? Photosynthesis is the amazing process where plants use sunlight to turn carbon dioxide and water into glucose and oxygen. The equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
This reaction happens in chlorophyll and is endothermic, meaning it takes in energy from the environment. Three main factors can limit how fast photosynthesis happens: temperature, light intensity, and CO₂ concentration.
Temperature needs to be just right - too cold and the plant slows right down, too hot and enzymes get damaged. Light is essential, but too much can actually harm plant cells. CO₂ is like the plant's food ingredient for making glucose, though too much can slow things down.
Once plants make glucose, they're pretty clever with it. They turn it into cellulose for strong cell walls, combine it with minerals to make amino acids, convert it to lipids for seeds, and store it as starch in roots and stems for later use.
Quick Tip: If a graph shows photosynthesis rate plateauing (levelling off), it means something else has become the limiting factor!
Respiration - Releasing Energy for Life
Respiration is how every single cell in your body releases energy from glucose - and it's happening right now as you read this! Unlike photosynthesis, this is an exothermic reaction that releases energy for everything you do.
Aerobic respiration uses oxygen and follows this equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O. This happens mainly in the mitochondria and is super efficient at releasing energy for muscle movement and keeping warm-blooded animals toasty.
But what happens when there's no oxygen? Anaerobic respiration kicks in! In animals, glucose breaks down into lactic acid - that's what makes your muscles ache after intense exercise. In plants and yeast, it's different: glucose becomes ethanol and CO₂.
This fermentation process is brilliant for making things we use daily. The CO₂ makes bread rise, whilst the ethanol is used in alcoholic drinks. Pretty cool how the same process that helps you sprint also helps bake your morning toast!
Remember: Anaerobic respiration is incomplete breakdown of glucose - it releases much less energy than aerobic respiration.
Investigating Photosynthesis in the Lab
You can actually measure photosynthesis happening using some simple lab kit and pondweed! The oxygen bubbles the plant produces give away how fast photosynthesis is occurring.
Set up your boiling tube filled with sodium hydrogencarbonate solution (this provides extra CO₂). Pop in your pondweed with a fresh cut end and position it at different distances from a lamp - try 10cm, 20cm, 30cm, and 40cm away.
After letting it settle for 5 minutes, count the oxygen bubbles produced in one minute using your stopwatch. Repeat this twice more and calculate the mean for accuracy. Do this at each distance from the light source.
When you plot your results on a graph, you'll see that light intensity directly affects the rate of photosynthesis. The closer to the light, the more bubbles you'll count - until another factor becomes limiting!
Lab Tip: Always cut the pondweed end fresh before starting - this ensures clear oxygen bubble release for accurate counting.
Exercise and Your Body's Energy Systems
When you exercise, your muscles are constantly contracting and need loads more energy than usual. Your body responds brilliantly by increasing breathing rate, breath volume, and heart rate to get more oxygen to those working muscles.
You'll also start sweating to keep your body temperature stable. All this extra activity ramps up your metabolism - that's all the chemical reactions controlled by enzymes that keep you alive and moving.
One downside of intense exercise is that excess protein gets broken down, producing urea as waste that needs removing from your body. This is why staying hydrated during and after exercise is so important.
Your body is basically a fantastic energy-processing machine that adapts instantly to whatever you're doing. Whether you're sitting in class or sprinting for the bus, these energy systems are constantly working to keep you going.
Fitness Fact: The fitter you are, the more efficiently your body can deliver oxygen to muscles, meaning you can exercise harder for longer!
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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.
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Best app on earth! no words because it’s too good
Thomas R
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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!
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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
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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.
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
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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
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 Bioenergetics in Biology
leema .
@leema.x
Bioenergetics is all about how living things get and use energy to stay alive. Plants capture energy from sunlight through photosynthesis, whilst all living things release energy through respiration.
Photosynthesis - How Plants Make Food
Ever wondered how plants create their own food? Photosynthesis is the amazing process where plants use sunlight to turn carbon dioxide and water into glucose and oxygen. The equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
This reaction happens in chlorophyll and is endothermic, meaning it takes in energy from the environment. Three main factors can limit how fast photosynthesis happens: temperature, light intensity, and CO₂ concentration.
Temperature needs to be just right - too cold and the plant slows right down, too hot and enzymes get damaged. Light is essential, but too much can actually harm plant cells. CO₂ is like the plant's food ingredient for making glucose, though too much can slow things down.
Once plants make glucose, they're pretty clever with it. They turn it into cellulose for strong cell walls, combine it with minerals to make amino acids, convert it to lipids for seeds, and store it as starch in roots and stems for later use.
Quick Tip: If a graph shows photosynthesis rate plateauing (levelling off), it means something else has become the limiting factor!
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Respiration - Releasing Energy for Life
Respiration is how every single cell in your body releases energy from glucose - and it's happening right now as you read this! Unlike photosynthesis, this is an exothermic reaction that releases energy for everything you do.
Aerobic respiration uses oxygen and follows this equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O. This happens mainly in the mitochondria and is super efficient at releasing energy for muscle movement and keeping warm-blooded animals toasty.
But what happens when there's no oxygen? Anaerobic respiration kicks in! In animals, glucose breaks down into lactic acid - that's what makes your muscles ache after intense exercise. In plants and yeast, it's different: glucose becomes ethanol and CO₂.
This fermentation process is brilliant for making things we use daily. The CO₂ makes bread rise, whilst the ethanol is used in alcoholic drinks. Pretty cool how the same process that helps you sprint also helps bake your morning toast!
Remember: Anaerobic respiration is incomplete breakdown of glucose - it releases much less energy than aerobic respiration.
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Investigating Photosynthesis in the Lab
You can actually measure photosynthesis happening using some simple lab kit and pondweed! The oxygen bubbles the plant produces give away how fast photosynthesis is occurring.
Set up your boiling tube filled with sodium hydrogencarbonate solution (this provides extra CO₂). Pop in your pondweed with a fresh cut end and position it at different distances from a lamp - try 10cm, 20cm, 30cm, and 40cm away.
After letting it settle for 5 minutes, count the oxygen bubbles produced in one minute using your stopwatch. Repeat this twice more and calculate the mean for accuracy. Do this at each distance from the light source.
When you plot your results on a graph, you'll see that light intensity directly affects the rate of photosynthesis. The closer to the light, the more bubbles you'll count - until another factor becomes limiting!
Lab Tip: Always cut the pondweed end fresh before starting - this ensures clear oxygen bubble release for accurate counting.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Exercise and Your Body's Energy Systems
When you exercise, your muscles are constantly contracting and need loads more energy than usual. Your body responds brilliantly by increasing breathing rate, breath volume, and heart rate to get more oxygen to those working muscles.
You'll also start sweating to keep your body temperature stable. All this extra activity ramps up your metabolism - that's all the chemical reactions controlled by enzymes that keep you alive and moving.
One downside of intense exercise is that excess protein gets broken down, producing urea as waste that needs removing from your body. This is why staying hydrated during and after exercise is so important.
Your body is basically a fantastic energy-processing machine that adapts instantly to whatever you're doing. Whether you're sitting in class or sprinting for the bus, these energy systems are constantly working to keep you going.
Fitness Fact: The fitter you are, the more efficiently your body can deliver oxygen to muscles, meaning you can exercise harder for longer!
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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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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