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Responding to change (a2 only)
Infection and response
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Energy transfers (a2 only)
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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
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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
World war one
Britain: 1509 -1745
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Biology
12 Dec 2025
623
3 pages
Toby king @tobyugbor_lcqq
Osmosis and diffusion are key processes in cellular biology, affecting the movement of water and particles across cell... Show more
Diffusion is another critical process in cellular biology, closely related to osmosis but involving the movement of particles rather than just water.
Definition Diffusion is the net movement of particles from an area of high concentration to an area of low concentration, passing through a membrane following the concentration gradient.
The effects of concentration gradient on diffusion rate are significant
Highlight The larger the difference in concentration between two areas, the greater the concentration gradient, resulting in a faster rate of diffusion.
Several factors influence the rate of diffusion
These factors demonstrate how environmental and structural conditions can impact cellular processes, highlighting the complexity of biological systems.
Active transport is a crucial cellular process that differs from osmosis and diffusion in its energy requirements and direction of particle movement.
Definition Active transport is the net movement of particles from an area of low concentration to an area of high concentration, going against the concentration gradient. This process requires energy.
The active transport and energy requirement in cells is essential for various biological functions
Sugar absorption in the gut This process allows sugar to be absorbed from the gut into the bloodstream for cell respiration.
Mineral absorption in plants Active transport enables plants to absorb minerals needed for growth, even when these minerals are in low concentrations in the soil.
Example In the human digestive system, glucose is actively transported from the intestines into the bloodstream, even when its concentration is higher in the blood. This ensures efficient nutrient uptake.
These examples illustrate how active transport is vital for maintaining proper cellular function and overall organism health, demonstrating the sophisticated mechanisms cells employ to regulate their internal environment.
Osmosis is a fundamental biological process that plays a crucial role in cellular functions. This page explores the concept of osmosis and how it can be investigated through experimentation.
Definition Osmosis is the movement of water across a partially permeable membrane from a dilute to a less concentrated solution.
The goal of osmosis is to equalize the concentration on both sides of the membrane. To investigate this process, scientists use controlled experiments with variables.
Vocabulary
- Independent variable What is being controlled throughout the experiment
- Dependent variable What is being measured as a result of the experiment
An osmosis experiment with potato slices is a common method to demonstrate this process
Highlight The percentage change formula is crucial for analyzing the results of osmosis experiments
Percentage Change = / Initial value × 100
This formula helps quantify the water movement in or out of the potato slices, providing concrete data on the osmosis process.
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.
13
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential strategies for tackling extended response questions in National 5 Biology. This resource covers key concepts such as cellular transport, fermentation processes, and human body systems, providing insights into effective answering techniques. Ideal for students preparing for exams, this summary includes past paper questions and marking schemes to enhance understanding and performance.
BiologyExplore key concepts in cell biology, including microscopy techniques, bacterial growth, mitosis, stem cells, and transport mechanisms like diffusion and osmosis. This summary covers essential practicals and theoretical knowledge for AQA Biology, perfect for exam preparation.
BiologyExplore the essential processes of diffusion, osmosis, and active transport in cells. This summary covers key concepts such as concentration gradients, the role of temperature and surface area in diffusion, and the mechanisms of cellular transport, including the function of transport proteins and the significance of cellular respiration. Ideal for students studying plant transport systems and cellular processes.
BiologyExplore comprehensive insights into 6-mark QER questions for the WJEC Biology GCSE. This resource covers key topics such as substance exchange, the carbon and nitrogen cycles, respiration, and the circulatory system, providing essential knowledge for exam preparation.
BiologyExplore key concepts in homeostasis, including hormonal coordination, the nervous system, and the impact of abiotic and biotic factors on ecosystems. This comprehensive study note covers essential topics such as glucose regulation, the menstrual cycle, and the importance of biodiversity. Ideal for GCSE Biology revision, this resource provides a clear overview of cellular processes, energy transfer, and the dynamics of ecosystems. Type: Summary.
BiologyExplore key concepts in cell biology, including specialized exchange surfaces, diffusion, osmosis, and active transport. This summary covers essential adaptations for efficient substance exchange in multicellular organisms, cell division, and the structure of eukaryotic and prokaryotic cells. Ideal for AQA Combined Science (Higher Tier) revision.
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
Toby king
@tobyugbor_lcqq
Osmosis and diffusion are key processes in cellular biology, affecting the movement of water and particles across cell membranes.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Diffusion is another critical process in cellular biology, closely related to osmosis but involving the movement of particles rather than just water.
Definition: Diffusion is the net movement of particles from an area of high concentration to an area of low concentration, passing through a membrane following the concentration gradient.
The effects of concentration gradient on diffusion rate are significant:
Highlight: The larger the difference in concentration between two areas, the greater the concentration gradient, resulting in a faster rate of diffusion.
Several factors influence the rate of diffusion:
These factors demonstrate how environmental and structural conditions can impact cellular processes, highlighting the complexity of biological systems.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Active transport is a crucial cellular process that differs from osmosis and diffusion in its energy requirements and direction of particle movement.
Definition: Active transport is the net movement of particles from an area of low concentration to an area of high concentration, going against the concentration gradient. This process requires energy.
The active transport and energy requirement in cells is essential for various biological functions:
Sugar absorption in the gut: This process allows sugar to be absorbed from the gut into the bloodstream for cell respiration.
Mineral absorption in plants: Active transport enables plants to absorb minerals needed for growth, even when these minerals are in low concentrations in the soil.
Example: In the human digestive system, glucose is actively transported from the intestines into the bloodstream, even when its concentration is higher in the blood. This ensures efficient nutrient uptake.
These examples illustrate how active transport is vital for maintaining proper cellular function and overall organism health, demonstrating the sophisticated mechanisms cells employ to regulate their internal environment.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Osmosis is a fundamental biological process that plays a crucial role in cellular functions. This page explores the concept of osmosis and how it can be investigated through experimentation.
Definition: Osmosis is the movement of water across a partially permeable membrane from a dilute to a less concentrated solution.
The goal of osmosis is to equalize the concentration on both sides of the membrane. To investigate this process, scientists use controlled experiments with variables.
Vocabulary:
- Independent variable: What is being controlled throughout the experiment
- Dependent variable: What is being measured as a result of the experiment
An osmosis experiment with potato slices is a common method to demonstrate this process:
Highlight: The percentage change formula is crucial for analyzing the results of osmosis experiments:
Percentage Change = / Initial value × 100
This formula helps quantify the water movement in or out of the potato slices, providing concrete data on the osmosis process.
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.
13
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential strategies for tackling extended response questions in National 5 Biology. This resource covers key concepts such as cellular transport, fermentation processes, and human body systems, providing insights into effective answering techniques. Ideal for students preparing for exams, this summary includes past paper questions and marking schemes to enhance understanding and performance.
BiologyExplore key concepts in cell biology, including microscopy techniques, bacterial growth, mitosis, stem cells, and transport mechanisms like diffusion and osmosis. This summary covers essential practicals and theoretical knowledge for AQA Biology, perfect for exam preparation.
BiologyExplore the essential processes of diffusion, osmosis, and active transport in cells. This summary covers key concepts such as concentration gradients, the role of temperature and surface area in diffusion, and the mechanisms of cellular transport, including the function of transport proteins and the significance of cellular respiration. Ideal for students studying plant transport systems and cellular processes.
BiologyExplore comprehensive insights into 6-mark QER questions for the WJEC Biology GCSE. This resource covers key topics such as substance exchange, the carbon and nitrogen cycles, respiration, and the circulatory system, providing essential knowledge for exam preparation.
BiologyExplore key concepts in homeostasis, including hormonal coordination, the nervous system, and the impact of abiotic and biotic factors on ecosystems. This comprehensive study note covers essential topics such as glucose regulation, the menstrual cycle, and the importance of biodiversity. Ideal for GCSE Biology revision, this resource provides a clear overview of cellular processes, energy transfer, and the dynamics of ecosystems. Type: Summary.
BiologyExplore key concepts in cell biology, including specialized exchange surfaces, diffusion, osmosis, and active transport. This summary covers essential adaptations for efficient substance exchange in multicellular organisms, cell division, and the structure of eukaryotic and prokaryotic cells. Ideal for AQA Combined Science (Higher Tier) revision.
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