Subjects
Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
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
World war one
Britain: 1509 -1745
Show all topics
6
0
sheila
04/12/2025
Biology
Polysaccharides
173
•
4 Dec 2025
•
Polysaccharides are massive carbohydrate molecules made from loads of sugar... Show more
Ever wonder how plants store energy for later? Starch is their clever solution - it's like a molecular battery pack made from glucose units. This polysaccharide comes in two forms that work together brilliantly.
Amylose forms a neat coiled structure using (1,4) glycosidic bonds between alpha glucose molecules. Think of it as a tightly wound spring that stores loads of glucose in a compact space.
Amylopectin takes things further with its branched structure, adding (1,6) glycosidic bonds to create multiple branches. This branching is genius - it creates tons more "ends" where enzymes can quickly grab glucose when the plant needs energy fast.
Both forms share brilliant properties: they're insoluble (so they won't mess with the plant's water balance), incredibly compact (loads of energy in tiny spaces), and perfect for long-term glucose storage.
Quick Tip: Remember that branches = speed! The more branches, the faster energy can be released.
Animals needed their own energy storage system, and glycogen is their answer - basically the animal version of starch but even more efficient. You'll find glycogen granules packed into your liver and muscle cells, ready for action.
Like starch, glycogen is made from alpha glucose units, but it's way more branched than amylopectin. These branches form through the same (1,4) and (1,6) glycosidic bonds, creating a coiled and highly branched structure.
What makes glycogen brilliant for animals? It's even more compact than starch, completely insoluble, and those numerous branches mean enzymes can convert it back to glucose lightning-fast. Perfect for when you need energy quickly - like during exercise or between meals.
Remember: More branches in glycogen = faster energy release than plant starch!
Cellulose isn't about energy storage - it's all about strength and structure. Made from beta glucose (note: beta, not alpha), this polysaccharide creates the tough cell walls that keep plants standing tall.
The structure is fascinating: parallel chains of beta glucose link together through hydrogen bonds to form microfibrils. These microfibrils then group into macrofibrils, which finally form cellulose fibres - the building blocks of plant cell walls.
This creates something amazing: cell walls that are both strong and permeable. The cellulose structure lets water and nutrients pass through whilst providing incredible strength. During osmosis, these walls resist the outward pressure from cell contents, preventing cells from bursting and keeping them turgid (properly inflated).
Unlike starch and glycogen, cellulose is completely insoluble and unbranched - perfect for its structural job.
Key Point: Beta glucose in cellulose vs alpha glucose in starch/glycogen makes all the difference in function!
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.
App 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
Polysaccharides are massive carbohydrate molecules made from loads of sugar units stuck together - think of them as nature's storage solutions and structural materials. These biological powerhouses include starch (plant energy storage), glycogen (animal energy storage), and cellulose (plant cell... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wonder how plants store energy for later? Starch is their clever solution - it's like a molecular battery pack made from glucose units. This polysaccharide comes in two forms that work together brilliantly.
Amylose forms a neat coiled structure using (1,4) glycosidic bonds between alpha glucose molecules. Think of it as a tightly wound spring that stores loads of glucose in a compact space.
Amylopectin takes things further with its branched structure, adding (1,6) glycosidic bonds to create multiple branches. This branching is genius - it creates tons more "ends" where enzymes can quickly grab glucose when the plant needs energy fast.
Both forms share brilliant properties: they're insoluble (so they won't mess with the plant's water balance), incredibly compact (loads of energy in tiny spaces), and perfect for long-term glucose storage.
Quick Tip: Remember that branches = speed! The more branches, the faster energy can be released.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Animals needed their own energy storage system, and glycogen is their answer - basically the animal version of starch but even more efficient. You'll find glycogen granules packed into your liver and muscle cells, ready for action.
Like starch, glycogen is made from alpha glucose units, but it's way more branched than amylopectin. These branches form through the same (1,4) and (1,6) glycosidic bonds, creating a coiled and highly branched structure.
What makes glycogen brilliant for animals? It's even more compact than starch, completely insoluble, and those numerous branches mean enzymes can convert it back to glucose lightning-fast. Perfect for when you need energy quickly - like during exercise or between meals.
Remember: More branches in glycogen = faster energy release than plant starch!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cellulose isn't about energy storage - it's all about strength and structure. Made from beta glucose (note: beta, not alpha), this polysaccharide creates the tough cell walls that keep plants standing tall.
The structure is fascinating: parallel chains of beta glucose link together through hydrogen bonds to form microfibrils. These microfibrils then group into macrofibrils, which finally form cellulose fibres - the building blocks of plant cell walls.
This creates something amazing: cell walls that are both strong and permeable. The cellulose structure lets water and nutrients pass through whilst providing incredible strength. During osmosis, these walls resist the outward pressure from cell contents, preventing cells from bursting and keeping them turgid (properly inflated).
Unlike starch and glycogen, cellulose is completely insoluble and unbranched - perfect for its structural job.
Key Point: Beta glucose in cellulose vs alpha glucose in starch/glycogen makes all the difference in function!
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.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential carbohydrate testing methods including the iodine test for starch and Benedict's test for reducing sugars. This summary covers the structure of carbohydrates, the significance of polysaccharides like starch and glycogen, and the biochemical reactions involved in carbohydrate digestion. Ideal for AQA A-Level Biology students.
BiologyExplore the key types of polysaccharides, including cellulose, glycogen, and starch. This summary highlights their structures, bonding types, and biological significance, tailored for A-level Biology students. Understand the role of glycosidic bonds and the implications for digestion and energy storage.
BiologyExplore the fundamentals of biological molecules, including monomers, polymers, and carbohydrates. This summary covers key concepts such as monosaccharides, disaccharides, and the structure of glucose. Ideal for A-level Biology students seeking to understand the building blocks of life.
BiologyExplore the essential characteristics of monosaccharides, including their structure, types (pentose and hexose), and properties such as solubility in water. This summary highlights key concepts like glucose, fructose, and galactose, and explains the significance of hydrogen bonding in their hydrophilic nature. Ideal for students studying biological molecules.
BiologyExplore the diverse structures and functions of carbohydrates, including monosaccharides like glucose and fructose, disaccharides such as sucrose and lactose, and polysaccharides like starch and cellulose. This summary covers key concepts such as glycosidic bonds, hydrophilicity, and the role of carbohydrates in biological systems. Ideal for students studying biomolecules and macromolecules.
BiologyExplore the structure and function of carbohydrates, including monosaccharides, disaccharides, and polysaccharides. This summary covers key concepts such as glycosidic bonds, condensation and hydrolysis reactions, and the roles of starch, glycogen, and cellulose in biological systems. Ideal for A Level Biology students studying biological molecules.
BiologyApp 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