Maths
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Responding to change (a2 only)
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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
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24
•
4 Dec 2025
•
Victor
@the1andonly
Polysaccharides are massive carbohydrate molecules made from hundreds or thousands... Show more
Right, let's sort out the carbohydrate family tree first. Monosaccharides are your simple sugars like glucose - the basic building blocks. When two of these join up, you get disaccharides (like maltose or sucrose), and when loads of them chain together, you've got polysaccharides.
The key thing to remember is the difference between alpha-glucose and beta-glucose. In alpha-glucose, the hydroxyl group on carbon 1 points downwards, whilst the hydrogen sits above it. This might seem like a tiny detail, but it completely changes what the final polysaccharide can do.
Common disaccharides you need to know include maltose (two glucose molecules), sucrose , and lactose . They all have the same chemical formula: C₁₂H₂₂O₁₁.
Key Insight: The orientation of that hydroxyl group on carbon 1 determines whether you get storage molecules like starch or structural powerhouses like cellulose.
Polysaccharides are essentially polymers - long chains of monosaccharide molecules held together by glycosidic bonds formed through condensation reactions. Because these molecules are absolutely massive, they're insoluble in water, which makes them perfect for storage jobs.
When your body needs energy, these polysaccharides get broken down through hydrolysis back into smaller sugars. The three main players you need to know are starch, glycogen, and cellulose - each with completely different roles.
Starch is found in plants and consists of two parts: amylose (which forms neat helical chains) and amylopectin (which branches out). Both are made from alpha-glucose molecules, making them perfect glucose storage units for plants.
Remember This: Size matters here - polysaccharides are too big to escape through cell membranes, so they stay put exactly where they're needed.
Think of starch as a plant's energy savings account. It's actually a mixture of two molecules: amylose (straight chains that coil into helixes) and amylopectin (branched chains). Both are made from alpha-glucose, but their different structures give them unique properties.
Glycogen is essentially the animal version of starch, but it's even more highly branched than amylopectin. Humans store glycogen mainly in liver and muscle cells, ready to release glucose when energy demands spike.
Both molecules share brilliant storage features: they're insoluble (so they don't mess with water balance), highly branched (meaning enzymes can attack from multiple points for quick breakdown), and compact (you can pack loads of glucose into small spaces).
The branching is particularly clever - more branches mean more "ends" where enzymes can start chopping the molecule apart, giving you rapid glucose release when you need energy fast.
Exam Tip: Remember that glycogen is more branched than starch, which makes sense since animals often need quick energy bursts for movement.
Cellulose is completely different from starch and glycogen because it's made from beta-glucose instead of alpha-glucose. This seemingly small change creates one of nature's strongest materials - the main component of plant cell walls.
Here's where it gets interesting: every second beta-glucose molecule is flipped 180° (like doing a handstand), creating perfectly straight, rigid chains. These chains line up parallel to each other and get locked together by thousands of hydrogen bonds.
The structure builds up in stages: individual chains form microfibrils, which bundle together into macrofibrils, which finally create cellulose fibres. Each hydrogen bond is weak on its own, but when you've got thousands working together, the result is incredibly strong.
This is why plant cell walls are so tough and why cellulose makes excellent paper and textiles. The straight chains and extensive hydrogen bonding create a material that's both flexible and incredibly strong.
Think About It: Wood, cotton, and paper are all mainly cellulose - that's the power of those perfectly aligned beta-glucose chains working together.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Quotes from every main character
English LiteratureApp Store
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
Victor
@the1andonly
Polysaccharides are massive carbohydrate molecules made from hundreds or thousands of sugar units linked together - think of them as the heavyweight champions of the carb world. You'll find these molecular giants everywhere from the starch in your chips to... Show more
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Right, let's sort out the carbohydrate family tree first. Monosaccharides are your simple sugars like glucose - the basic building blocks. When two of these join up, you get disaccharides (like maltose or sucrose), and when loads of them chain together, you've got polysaccharides.
The key thing to remember is the difference between alpha-glucose and beta-glucose. In alpha-glucose, the hydroxyl group on carbon 1 points downwards, whilst the hydrogen sits above it. This might seem like a tiny detail, but it completely changes what the final polysaccharide can do.
Common disaccharides you need to know include maltose (two glucose molecules), sucrose , and lactose . They all have the same chemical formula: C₁₂H₂₂O₁₁.
Key Insight: The orientation of that hydroxyl group on carbon 1 determines whether you get storage molecules like starch or structural powerhouses like cellulose.
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Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Polysaccharides are essentially polymers - long chains of monosaccharide molecules held together by glycosidic bonds formed through condensation reactions. Because these molecules are absolutely massive, they're insoluble in water, which makes them perfect for storage jobs.
When your body needs energy, these polysaccharides get broken down through hydrolysis back into smaller sugars. The three main players you need to know are starch, glycogen, and cellulose - each with completely different roles.
Starch is found in plants and consists of two parts: amylose (which forms neat helical chains) and amylopectin (which branches out). Both are made from alpha-glucose molecules, making them perfect glucose storage units for plants.
Remember This: Size matters here - polysaccharides are too big to escape through cell membranes, so they stay put exactly where they're needed.
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Improve your grades
Join milions of students
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Think of starch as a plant's energy savings account. It's actually a mixture of two molecules: amylose (straight chains that coil into helixes) and amylopectin (branched chains). Both are made from alpha-glucose, but their different structures give them unique properties.
Glycogen is essentially the animal version of starch, but it's even more highly branched than amylopectin. Humans store glycogen mainly in liver and muscle cells, ready to release glucose when energy demands spike.
Both molecules share brilliant storage features: they're insoluble (so they don't mess with water balance), highly branched (meaning enzymes can attack from multiple points for quick breakdown), and compact (you can pack loads of glucose into small spaces).
The branching is particularly clever - more branches mean more "ends" where enzymes can start chopping the molecule apart, giving you rapid glucose release when you need energy fast.
Exam Tip: Remember that glycogen is more branched than starch, which makes sense since animals often need quick energy bursts for movement.
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Improve your grades
Join milions of students
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Cellulose is completely different from starch and glycogen because it's made from beta-glucose instead of alpha-glucose. This seemingly small change creates one of nature's strongest materials - the main component of plant cell walls.
Here's where it gets interesting: every second beta-glucose molecule is flipped 180° (like doing a handstand), creating perfectly straight, rigid chains. These chains line up parallel to each other and get locked together by thousands of hydrogen bonds.
The structure builds up in stages: individual chains form microfibrils, which bundle together into macrofibrils, which finally create cellulose fibres. Each hydrogen bond is weak on its own, but when you've got thousands working together, the result is incredibly strong.
This is why plant cell walls are so tough and why cellulose makes excellent paper and textiles. The straight chains and extensive hydrogen bonding create a material that's both flexible and incredibly strong.
Think About It: Wood, cotton, and paper are all mainly cellulose - that's the power of those perfectly aligned beta-glucose chains working together.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
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.
You can download the app from Google Play Store and Apple App Store.
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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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Quotes from every main character
English LiteratureApp Store
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
Sociology