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)
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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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Chemistry
13 Dec 2025
214
4 pages
Polymers are everywhere around you - from the plastic bottles you drink from to the DNA in your... Show more
Ever wondered what makes plastic bags stretchy and strong? It's all about polymers - giant molecules made by joining thousands of small molecules called monomers together. Think of it like building a massive LEGO structure from individual bricks.
Different monomers create polymers with completely different properties. Ethene (C₂H₄) creates polythene for carrier bags and bottles, whilst propene (C₃H₆) makes the super-tough poly(propene) used in carpets and milk crates.
The magic happens when monomers link up end-to-end, forming long chains with thousands of carbon atoms as the 'backbone'. This process transforms simple gases into the plastics that shape our daily lives.
Quick fact Both ethene and propene come from crude oil - that's why plastic production is linked to the oil industry!
You'll encounter two main ways that polymers form, and knowing the difference is crucial for your exams. Addition polymerisation is the simpler process - alkene molecules join together when their double bonds 'open up' and connect to neighbouring molecules. Only one product forms the polymer itself.
Condensation polymerisation works differently and produces two products the main polymer plus a small molecule (usually water or hydrogen chloride). This process typically uses two different types of monomers, each with specific functional groups that react together.
Polyesters are perfect examples of condensation polymers. They form when alcohol monomers react with carboxylic acid monomers , creating ester links and releasing water molecules.
When you're drawing polymer structures in exams, remember to show the smallest repeating unit in brackets - this represents the pattern that continues thousands of times.
Exam tip If you see water being produced, it's condensation polymerisation. If there's only one product, it's addition polymerisation.
Your body is essentially a polymer factory! Natural polymers like starch, cellulose, and proteins all form through condensation polymerisation, just like synthetic plastics.
Polysaccharides form when glucose monomers (C₆H₁₂O₆) link together. Plants make starch for energy storage and cellulose for structural support - both from the same glucose building blocks but with different arrangements. It's amazing how changing the connections creates completely different properties.
Proteins are even more fascinating because they use 20 different amino acid monomers. Each amino acid has both a basic group and an acidic group , allowing them to link via peptide bonds. The sequence of amino acids determines whether you get hair, muscle, or enzymes.
DNA represents the ultimate natural polymer - it stores the genetic code that determines every protein sequence in your body. Made from nucleotide monomers, DNA forms through condensation polymerisation to create the famous double helix structure.
Mind-blowing fact Your DNA contains millions of nucleotide monomers arranged in a specific sequence that makes you uniquely you!
DNA (deoxyribonucleic acid) isn't just another polymer - it's the molecule that makes life possible. This polynucleotide forms when millions of nucleotide monomers join through condensation polymerisation, releasing water molecules in the process.
The famous double helix structure consists of two polymer strands running in opposite directions. Each strand has a backbone of sugar molecules (deoxyribose) bonded to phosphate groups, with four different types of bases attached.
What makes DNA special is how these two strands are held together by intermolecular forces between complementary bases. This allows DNA to store vast amounts of genetic information whilst remaining stable enough to pass from generation to generation.
The genetic code within DNA determines the exact sequence of amino acids in every protein your body makes. When cells need specific proteins, they read the DNA code and build proteins with precisely the right amino acid sequence.
Amazing fact If you could stretch out all the DNA in one human cell, it would reach about 2 metres long!
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.
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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
Polymers are everywhere around you - from the plastic bottles you drink from to the DNA in your cells. Understanding how these massive molecules form from tiny building blocks called monomers will help you grasp one of chemistry's most important... Show more
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Ever wondered what makes plastic bags stretchy and strong? It's all about polymers - giant molecules made by joining thousands of small molecules called monomers together. Think of it like building a massive LEGO structure from individual bricks.
Different monomers create polymers with completely different properties. Ethene (C₂H₄) creates polythene for carrier bags and bottles, whilst propene (C₃H₆) makes the super-tough poly(propene) used in carpets and milk crates.
The magic happens when monomers link up end-to-end, forming long chains with thousands of carbon atoms as the 'backbone'. This process transforms simple gases into the plastics that shape our daily lives.
Quick fact: Both ethene and propene come from crude oil - that's why plastic production is linked to the oil industry!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
You'll encounter two main ways that polymers form, and knowing the difference is crucial for your exams. Addition polymerisation is the simpler process - alkene molecules join together when their double bonds 'open up' and connect to neighbouring molecules. Only one product forms: the polymer itself.
Condensation polymerisation works differently and produces two products: the main polymer plus a small molecule (usually water or hydrogen chloride). This process typically uses two different types of monomers, each with specific functional groups that react together.
Polyesters are perfect examples of condensation polymers. They form when alcohol monomers react with carboxylic acid monomers , creating ester links and releasing water molecules.
When you're drawing polymer structures in exams, remember to show the smallest repeating unit in brackets - this represents the pattern that continues thousands of times.
Exam tip: If you see water being produced, it's condensation polymerisation. If there's only one product, it's addition polymerisation.
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your body is essentially a polymer factory! Natural polymers like starch, cellulose, and proteins all form through condensation polymerisation, just like synthetic plastics.
Polysaccharides form when glucose monomers (C₆H₁₂O₆) link together. Plants make starch for energy storage and cellulose for structural support - both from the same glucose building blocks but with different arrangements. It's amazing how changing the connections creates completely different properties.
Proteins are even more fascinating because they use 20 different amino acid monomers. Each amino acid has both a basic group and an acidic group , allowing them to link via peptide bonds. The sequence of amino acids determines whether you get hair, muscle, or enzymes.
DNA represents the ultimate natural polymer - it stores the genetic code that determines every protein sequence in your body. Made from nucleotide monomers, DNA forms through condensation polymerisation to create the famous double helix structure.
Mind-blowing fact: Your DNA contains millions of nucleotide monomers arranged in a specific sequence that makes you uniquely you!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
DNA (deoxyribonucleic acid) isn't just another polymer - it's the molecule that makes life possible. This polynucleotide forms when millions of nucleotide monomers join through condensation polymerisation, releasing water molecules in the process.
The famous double helix structure consists of two polymer strands running in opposite directions. Each strand has a backbone of sugar molecules (deoxyribose) bonded to phosphate groups, with four different types of bases attached.
What makes DNA special is how these two strands are held together by intermolecular forces between complementary bases. This allows DNA to store vast amounts of genetic information whilst remaining stable enough to pass from generation to generation.
The genetic code within DNA determines the exact sequence of amino acids in every protein your body makes. When cells need specific proteins, they read the DNA code and build proteins with precisely the right amino acid sequence.
Amazing fact: If you could stretch out all the DNA in one human cell, it would reach about 2 metres long!
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.
3
Smart Tools NEW
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