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
Biology
13 Dec 2025
166
2 pages
Gracey @gracey_irtg
Water is absolutely essential for all life on Earth, and understanding its unique properties will help you grasp... Show more
Ever wondered why water behaves so differently from other liquids? It all comes down to water being a dipolar molecule - this means it has slightly positive and negative ends that create hydrogen bonds between water molecules.
These hydrogen bonds give water some incredible properties. Water has a high specific heat capacity, which means it takes loads of energy to heat it up or cool it down. This acts like a natural buffer, protecting your body and other organisms from sudden temperature changes.
The latent heat of vaporisation is another game-changer - it takes massive amounts of energy to turn liquid water into vapour. That's exactly why sweating works so well to cool you down! Your body heat provides the energy needed to evaporate sweat from your skin.
Cohesion and surface tension happen because water molecules literally stick together through those hydrogen bonds. This lets water travel up plant stems and creates that "skin" effect you see on pond surfaces. Plus, water's transparency allows aquatic plants to photosynthesise even underwater.
Key Insight Water's role in metabolism is crucial - it breaks down biological molecules through hydrolysis and joins them together via condensation reactions.
Water isn't easily compressed, making it brilliant for structural support in living things. Think about how plants stay upright through turgor pressure or how some animals use water as a hydrostatic skeleton - it's nature's hydraulic system!
As a solvent, water dissolves practically everything organisms need. Gases like oxygen and carbon dioxide, waste products such as ammonia and urea, and essential inorganic ions all dissolve readily in water. This makes water the perfect medium for chemical reactions and enzyme activity.
Inorganic ions are absolutely vital and are found throughout your body in varying concentrations. Iron ions in haemoglobin help transport oxygen around your bloodstream. Phosphate ions form the backbone of DNA and store energy in ATP molecules.
Hydrogen ions determine pH levels, which directly affects how enzymes function - get this wrong and your metabolism stops working properly. Meanwhile, sodium ions are essential for transporting glucose and amino acids across cell membranes.
Remember These ions work together in solution, and water makes it all possible by keeping everything dissolved and mobile throughout your body.
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
cells, photosynthesis and more
BiologyExplore a comprehensive collection of past paper questions and mark schemes tailored for AQA GCSE Biology (8461). This resource covers key topics such as photosynthesis, respiration, genetics, and homeostasis, providing essential practice to help you achieve a Grade 9. Ideal for exam preparation and understanding complex biological concepts.
BiologyExplore key concepts from the OCR Gateway 2018 Biology Paper 1 Higher exam, covering essential topics such as photosynthesis, hormonal control, and the human reproductive system. This summary highlights critical areas for revision, including reaction times, DNA structure, and plant responses. Ideal for students preparing for their GCSE Biology exams.
BiologyBased on the CGP GCSE AQA Biology student book, my apologies if any of the answers are incorrect or if the questions confuse you lmao
BiologyExplore the intricacies of the human circulatory system and plant organization in this comprehensive study note. Covering key concepts such as blood vessels, heart structure, enzyme functions, and plant tissues, this resource is designed for quick revision before exams. Ideal for students preparing for higher-level biology assessments.
BiologyExplore a comprehensive analysis of the higher tier GCSE Biology Paper 1, covering key topics such as cancer, obesity, respiration, and enzyme activity. This resource includes detailed explanations of concepts like malignant tumors, the impact of obesity on health, and the role of amylase in digestion. Ideal for students preparing for their exams, this document provides essential information and practice questions to enhance understanding and performance.
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
Gracey
@gracey_irtg
Water is absolutely essential for all life on Earth, and understanding its unique properties will help you grasp how living organisms function. From keeping your body temperature stable to allowing plants to transport nutrients, water's special characteristics make it the... 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 wondered why water behaves so differently from other liquids? It all comes down to water being a dipolar molecule - this means it has slightly positive and negative ends that create hydrogen bonds between water molecules.
These hydrogen bonds give water some incredible properties. Water has a high specific heat capacity, which means it takes loads of energy to heat it up or cool it down. This acts like a natural buffer, protecting your body and other organisms from sudden temperature changes.
The latent heat of vaporisation is another game-changer - it takes massive amounts of energy to turn liquid water into vapour. That's exactly why sweating works so well to cool you down! Your body heat provides the energy needed to evaporate sweat from your skin.
Cohesion and surface tension happen because water molecules literally stick together through those hydrogen bonds. This lets water travel up plant stems and creates that "skin" effect you see on pond surfaces. Plus, water's transparency allows aquatic plants to photosynthesise even underwater.
Key Insight: Water's role in metabolism is crucial - it breaks down biological molecules through hydrolysis and joins them together via condensation reactions.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Water isn't easily compressed, making it brilliant for structural support in living things. Think about how plants stay upright through turgor pressure or how some animals use water as a hydrostatic skeleton - it's nature's hydraulic system!
As a solvent, water dissolves practically everything organisms need. Gases like oxygen and carbon dioxide, waste products such as ammonia and urea, and essential inorganic ions all dissolve readily in water. This makes water the perfect medium for chemical reactions and enzyme activity.
Inorganic ions are absolutely vital and are found throughout your body in varying concentrations. Iron ions in haemoglobin help transport oxygen around your bloodstream. Phosphate ions form the backbone of DNA and store energy in ATP molecules.
Hydrogen ions determine pH levels, which directly affects how enzymes function - get this wrong and your metabolism stops working properly. Meanwhile, sodium ions are essential for transporting glucose and amino acids across cell membranes.
Remember: These ions work together in solution, and water makes it all possible by keeping everything dissolved and mobile throughout your body.
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.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
cells, photosynthesis and more
BiologyExplore a comprehensive collection of past paper questions and mark schemes tailored for AQA GCSE Biology (8461). This resource covers key topics such as photosynthesis, respiration, genetics, and homeostasis, providing essential practice to help you achieve a Grade 9. Ideal for exam preparation and understanding complex biological concepts.
BiologyExplore key concepts from the OCR Gateway 2018 Biology Paper 1 Higher exam, covering essential topics such as photosynthesis, hormonal control, and the human reproductive system. This summary highlights critical areas for revision, including reaction times, DNA structure, and plant responses. Ideal for students preparing for their GCSE Biology exams.
BiologyBased on the CGP GCSE AQA Biology student book, my apologies if any of the answers are incorrect or if the questions confuse you lmao
BiologyExplore the intricacies of the human circulatory system and plant organization in this comprehensive study note. Covering key concepts such as blood vessels, heart structure, enzyme functions, and plant tissues, this resource is designed for quick revision before exams. Ideal for students preparing for higher-level biology assessments.
BiologyExplore a comprehensive analysis of the higher tier GCSE Biology Paper 1, covering key topics such as cancer, obesity, respiration, and enzyme activity. This resource includes detailed explanations of concepts like malignant tumors, the impact of obesity on health, and the role of amylase in digestion. Ideal for students preparing for their exams, this document provides essential information and practice questions to enhance understanding and performance.
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