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GCSE Edexcel Biology: Plant Structures and Their Functions Notes (B6)
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Photosynthesis Basics
Ever wondered how plants create their own food? Photosynthesis is the incredible process where plants use light energy to convert carbon dioxide and water into glucose and oxygen. This happens inside tiny structures called chloroplasts, which contain a green pigment called chlorophyll that absorbs light.
The equation you need to remember is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ . Photosynthesis is an endothermic reaction, meaning it takes in energy during the process.
Three main factors affect how fast photosynthesis happens: light intensity, temperature, and carbon dioxide concentration. Any of these can become a limiting factor - the thing that slows down the whole process when there's not enough of it.
Quick Tip: Think of limiting factors like the slowest person in a group project - they determine how fast the whole team can work!
How Plants Absorb Water and Minerals
Plants need water for four crucial reasons: carrying dissolved mineral ions around the plant, keeping cells rigid so they don't wilt, cooling leaves through evaporation, and of course, photosynthesis. Root hair cells are perfectly designed for this job with their large surface area and thin walls.
You'll need to understand three key transport processes. Diffusion moves particles from high to low concentration naturally. Osmosis specifically moves water particles across a semi-permeable membrane from high to low concentration. Active transport is different - it moves particles against the concentration gradient (low to high) using energy.
Semi-permeable membranes are selective barriers that only let specific particles pass through. Root hair cells use these processes brilliantly, with large vacuoles creating concentration gradients and no chloroplasts since they don't need sunlight underground.
Remember: Active transport is like swimming upstream - it needs energy because you're going against the natural flow!
Transpiration and Translocation
Plants have two main transport systems that work like a circulatory system. Xylem tissue transports water and mineral ions upwards from roots to shoots. These are dead cells with thick, hard walls to withstand pressure and pores for easy water flow.
Phloem tissue transports sugars around the plant and contains living cells with companion cells and mitochondria for active transport. Translocation is the movement of sucrose through phloem, whilst transpiration is water and mineral transport through xylem.
Four factors affect transpiration rate: wind (moves water molecules away from stomata), humidity (amount of water already in the air), temperature (particles move faster in heat), and light intensity (opens stomata for photosynthesis but water escapes too).
Think About It: Transpiration is like sweating - plants lose water to cool down, but too much can be harmful!
Leaf Adaptations for Photosynthesis
Plant leaves are engineering marvels, perfectly designed for photosynthesis. The waxy cuticle on top is waterproof, protecting the leaf. The upper epidermis is transparent, allowing light to pass through to the working cells below.
Palisade cells are packed with chloroplasts to absorb maximum light energy. Below them, the spongy mesophyll has air gaps allowing gases to move freely for gas exchange during photosynthesis.
The lower epidermis contains stomata (tiny pores) surrounded by guard cells that open and close to control gas exchange. This allows carbon dioxide in for photosynthesis and oxygen out as a waste product.
Fun Fact: A single leaf can have thousands of stomata - they're like tiny breathing holes that the plant can control!
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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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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.
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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.
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
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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
GCSE Edexcel Biology: Plant Structures and Their Functions Notes (B6)
~
@user2856739
Photosynthesis is one of the most important processes on Earth - it's how plants make their own food and produce the oxygen we breathe. Understanding how this works, along with how plants transport water and nutrients, will help you ace... Show more
Photosynthesis Basics
Ever wondered how plants create their own food? Photosynthesis is the incredible process where plants use light energy to convert carbon dioxide and water into glucose and oxygen. This happens inside tiny structures called chloroplasts, which contain a green pigment called chlorophyll that absorbs light.
The equation you need to remember is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ . Photosynthesis is an endothermic reaction, meaning it takes in energy during the process.
Three main factors affect how fast photosynthesis happens: light intensity, temperature, and carbon dioxide concentration. Any of these can become a limiting factor - the thing that slows down the whole process when there's not enough of it.
Quick Tip: Think of limiting factors like the slowest person in a group project - they determine how fast the whole team can work!
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How Plants Absorb Water and Minerals
Plants need water for four crucial reasons: carrying dissolved mineral ions around the plant, keeping cells rigid so they don't wilt, cooling leaves through evaporation, and of course, photosynthesis. Root hair cells are perfectly designed for this job with their large surface area and thin walls.
You'll need to understand three key transport processes. Diffusion moves particles from high to low concentration naturally. Osmosis specifically moves water particles across a semi-permeable membrane from high to low concentration. Active transport is different - it moves particles against the concentration gradient (low to high) using energy.
Semi-permeable membranes are selective barriers that only let specific particles pass through. Root hair cells use these processes brilliantly, with large vacuoles creating concentration gradients and no chloroplasts since they don't need sunlight underground.
Remember: Active transport is like swimming upstream - it needs energy because you're going against the natural flow!
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Transpiration and Translocation
Plants have two main transport systems that work like a circulatory system. Xylem tissue transports water and mineral ions upwards from roots to shoots. These are dead cells with thick, hard walls to withstand pressure and pores for easy water flow.
Phloem tissue transports sugars around the plant and contains living cells with companion cells and mitochondria for active transport. Translocation is the movement of sucrose through phloem, whilst transpiration is water and mineral transport through xylem.
Four factors affect transpiration rate: wind (moves water molecules away from stomata), humidity (amount of water already in the air), temperature (particles move faster in heat), and light intensity (opens stomata for photosynthesis but water escapes too).
Think About It: Transpiration is like sweating - plants lose water to cool down, but too much can be harmful!
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Leaf Adaptations for Photosynthesis
Plant leaves are engineering marvels, perfectly designed for photosynthesis. The waxy cuticle on top is waterproof, protecting the leaf. The upper epidermis is transparent, allowing light to pass through to the working cells below.
Palisade cells are packed with chloroplasts to absorb maximum light energy. Below them, the spongy mesophyll has air gaps allowing gases to move freely for gas exchange during photosynthesis.
The lower epidermis contains stomata (tiny pores) surrounded by guard cells that open and close to control gas exchange. This allows carbon dioxide in for photosynthesis and oxygen out as a waste product.
Fun Fact: A single leaf can have thousands of stomata - they're like tiny breathing holes that the plant can control!
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?
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Is Knowunity really free of charge?
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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