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8 Dec 2025
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Understanding Chloroplasts and Chlorophyll for Photosynthesis
O
Olivia
@oliviag
1 / 5
What is Photosynthesis?
Think of plants as the ultimate independent organisms - they're autotrophs, meaning they create their own food instead of hunting for it like we do. They pull this off by capturing sunlight and converting it into chemical energy stored in carbohydrates, basically splitting water molecules and combining the hydrogen with carbon dioxide.
Here's the magic formula you need to memorise: carbon dioxide + water → glucose + oxygen (using light energy). In chemical terms, that's 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
The crucial thing to remember about energy is that it can't be created or destroyed - only converted from one form to another. Plants are essentially solar-powered sugar factories, and without them, life on Earth would be impossible.
Quick Tip: The oxygen you're breathing right now? That's a byproduct of photosynthesis happening in plants around the world!
Chloroplasts - The Plant's Power Stations
Chloroplasts are where all the photosynthesis action happens - think of them as tiny green power stations inside plant cells. They're packed with membrane discs called thylakoids that stack up like pancakes to form structures called granum.
The space around these stacks is called the stroma, which contains all the enzymes needed to make ATP and build complex organic molecules. It's basically the chloroplast's workshop where the final products get assembled.
Each part has a specific job: the outer and inner membranes control what goes in and out, whilst the thylakoids are where the light-catching happens. Understanding this structure is crucial because each process of photosynthesis occurs in a specific location.
Remember: Stroma = workshop, Thylakoids = solar panels, Granum = stack of panels!
Chlorophyll - Nature's Solar Panels
Plants don't just have one type of chlorophyll - they've got a whole team of pigments working together. There's chlorophyll a , chlorophyll b , and the carotenoids like orange carotene and yellow xanthophyll.
Having different pigments is like having multiple types of solar panels - each one captures different wavelengths of light, making the whole system more efficient. Chlorophyll a is the main player found in all photosynthesising plants.
These pigments don't just float around randomly - they're attached to proteins on the thylakoid membranes. When a pigment molecule teams up with its protein, they form a photosystem, which is basically a light-harvesting unit.
Fun Fact: The reason leaves change colour in autumn is because chlorophyll breaks down, revealing the other pigments that were there all along!
Essential Chemistry - Oxidation and Reduction
Before diving deeper into photosynthesis, you need to master REDOX reactions . Remember the handy acronym OIL RIG: Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).
In biological terms, gaining hydrogen or losing oxygen means reduction, whilst losing hydrogen or gaining oxygen means oxidation. These always happen together - if something gets oxidised, something else must get reduced.
Take NADP, a crucial molecule in photosynthesis. When it gains hydrogen , it becomes reduced NADP. When it loses hydrogen , it gets oxidised back to its original form.
Study Tip: Think of NADP as a rechargeable battery - it can either give energy (oxidised) or store energy (reduced)!
The Two-Stage Process
Photosynthesis isn't a single reaction - it's a complex two-stage process that's beautifully coordinated. The light-dependent reactions happen first on the thylakoid membranes, followed by the light-independent reactions in the stroma.
Light-dependent reactions only occur during daylight and use solar energy to split water molecules (photolysis). This produces hydrogen atoms that get passed to NADP (forming NADPH) and generates ATP through photophosphorylation.
Light-independent reactions (also called the Calvin cycle) can happen anytime and use the NADPH and ATP from stage one. This is where CO₂ from the air gets reduced and converted into glucose in the stroma.
Key Point: Stage one captures and stores energy, stage two uses that stored energy to build glucose - it's like charging a battery then using it to power something!
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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
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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.
Anna
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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
Understanding Chloroplasts and Chlorophyll for Photosynthesis
O
Olivia
@oliviag
Ever wondered how plants make their own food whilst you're stuck buying yours from Tesco? Photosynthesis is literally the foundation of all life on Earth - it's how plants capture sunlight and turn it into the energy that feeds pretty... Show more
What is Photosynthesis?
Think of plants as the ultimate independent organisms - they're autotrophs, meaning they create their own food instead of hunting for it like we do. They pull this off by capturing sunlight and converting it into chemical energy stored in carbohydrates, basically splitting water molecules and combining the hydrogen with carbon dioxide.
Here's the magic formula you need to memorise: carbon dioxide + water → glucose + oxygen (using light energy). In chemical terms, that's 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
The crucial thing to remember about energy is that it can't be created or destroyed - only converted from one form to another. Plants are essentially solar-powered sugar factories, and without them, life on Earth would be impossible.
Quick Tip: The oxygen you're breathing right now? That's a byproduct of photosynthesis happening in plants around the world!
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Chloroplasts - The Plant's Power Stations
Chloroplasts are where all the photosynthesis action happens - think of them as tiny green power stations inside plant cells. They're packed with membrane discs called thylakoids that stack up like pancakes to form structures called granum.
The space around these stacks is called the stroma, which contains all the enzymes needed to make ATP and build complex organic molecules. It's basically the chloroplast's workshop where the final products get assembled.
Each part has a specific job: the outer and inner membranes control what goes in and out, whilst the thylakoids are where the light-catching happens. Understanding this structure is crucial because each process of photosynthesis occurs in a specific location.
Remember: Stroma = workshop, Thylakoids = solar panels, Granum = stack of panels!
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Improve your grades
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Chlorophyll - Nature's Solar Panels
Plants don't just have one type of chlorophyll - they've got a whole team of pigments working together. There's chlorophyll a , chlorophyll b , and the carotenoids like orange carotene and yellow xanthophyll.
Having different pigments is like having multiple types of solar panels - each one captures different wavelengths of light, making the whole system more efficient. Chlorophyll a is the main player found in all photosynthesising plants.
These pigments don't just float around randomly - they're attached to proteins on the thylakoid membranes. When a pigment molecule teams up with its protein, they form a photosystem, which is basically a light-harvesting unit.
Fun Fact: The reason leaves change colour in autumn is because chlorophyll breaks down, revealing the other pigments that were there all along!
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Essential Chemistry - Oxidation and Reduction
Before diving deeper into photosynthesis, you need to master REDOX reactions . Remember the handy acronym OIL RIG: Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons).
In biological terms, gaining hydrogen or losing oxygen means reduction, whilst losing hydrogen or gaining oxygen means oxidation. These always happen together - if something gets oxidised, something else must get reduced.
Take NADP, a crucial molecule in photosynthesis. When it gains hydrogen , it becomes reduced NADP. When it loses hydrogen , it gets oxidised back to its original form.
Study Tip: Think of NADP as a rechargeable battery - it can either give energy (oxidised) or store energy (reduced)!
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The Two-Stage Process
Photosynthesis isn't a single reaction - it's a complex two-stage process that's beautifully coordinated. The light-dependent reactions happen first on the thylakoid membranes, followed by the light-independent reactions in the stroma.
Light-dependent reactions only occur during daylight and use solar energy to split water molecules (photolysis). This produces hydrogen atoms that get passed to NADP (forming NADPH) and generates ATP through photophosphorylation.
Light-independent reactions (also called the Calvin cycle) can happen anytime and use the NADPH and ATP from stage one. This is where CO₂ from the air gets reduced and converted into glucose in the stroma.
Key Point: Stage one captures and stores energy, stage two uses that stored energy to build glucose - it's like charging a battery then using it to power something!
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?
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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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