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
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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
11 Dec 2025
97
67 pages
Ismail Saleem @ismailsaleem
This AQA GCSE Biology exam covers essential topics including plant biology, drug development, and the circulatory system. You'll... Show more
Ever wondered why plants can heal themselves or how they produce the medicines we use? This section explores the fascinating world of plant tissues and their medical applications.
Tissues are groups of similar cells working together to perform specific functions - think of them as specialised teams within an organism. Plants contain stem cells in their meristematic tissue, particularly at root tips, which can develop into any type of cell the plant needs.
Many of our everyday medicines originated from plants. Aspirin, one of the world's most common painkillers, actually comes from willow bark. This connection between plants and medicine shows why understanding plant biology is so relevant to modern healthcare.
Quick Tip Remember that meristematic tissue is where all the action happens - it's the plant's growth headquarters!
Scientists don't just randomly pick parts of plants when extracting medicines - there's proper science behind these decisions.
When extracting chemical A from deadly nightshade, scientists prefer using berries over leaves or roots for practical reasons. Berries might be easier to harvest, cause less damage to the plant, or simply be more accessible than digging up roots.
The data shows that whilst leaves contain more chemical A than berries (1.2g vs 0.7g per 100g), there are other factors to consider. Sustainable harvesting practices often influence which plant parts are used for drug extraction.
Real-World Connection This is exactly how pharmaceutical companies decide which parts of plants to use - balancing chemical content with practical harvesting concerns!
Maths isn't just for maths lessons - it's crucial for understanding biological processes and making real-world calculations.
When plants develop chlorosis (yellowing leaves), their chemical composition changes. If healthy leaves contain a certain amount of a compound, diseased leaves will contain less. You'll need to calculate these differences using percentages and unit conversions.
Chlorosis typically occurs due to nutrient deficiencies, particularly lack of magnesium or iron, which are essential for chlorophyll production. Without enough chlorophyll, leaves can't photosynthesise effectively and turn yellow.
Exam Strategy Always show your working clearly in calculations - you can still earn marks even if your final answer isn't quite right!
Before any medicine reaches your local pharmacy, it goes through rigorous testing - and there are excellent reasons why this process exists.
Clinical trials are essential because they test for safety and effectiveness in real humans. Drugs might work brilliantly in laboratory conditions but cause unexpected side effects in people, or simply not work as expected in the human body.
Bias in scientific reporting is a real problem, especially online. Reports might be biased because companies want to sell products, researchers have financial interests, or people simply want to promote their beliefs rather than facts.
The gold standard for ensuring scientific claims are valid is peer review - where other experts examine and critique research before it's published.
Critical Thinking Always question the source when you read health claims online - peer-reviewed scientific journals are far more reliable than social media posts!
Your heart is essentially a sophisticated pump system, and understanding its structure helps explain how blood circulates around your body.
The heart has four chambers working in perfect coordination. The left atrium receives oxygenated blood from the lungs, whilst the right ventricle pumps deoxygenated blood to the lungs for refreshing.
The pacemaker (sinoatrial node) is located in the right atrium and acts like your heart's natural timer, setting the rhythm for each heartbeat. This small group of cells ensures your heart beats regularly without you having to think about it.
Memory Trick Remember "right to lungs" - the right side of your heart deals with sending blood to your lungs for oxygen!
Arteries and veins have distinctly different structures because they perform different jobs in your circulatory system.
Arteries have thicker walls with more muscle tissue and elastic tissue because they must withstand high pressure as blood is pumped directly from the heart. Veins have thinner walls and contain valves to prevent backflow, since blood pressure is much lower on the return journey.
The pacemaker located in the right atrium controls your resting heart rate automatically. This natural pacemaker ensures your heart maintains a steady rhythm without conscious control.
Understanding Tip Think of arteries as high-pressure motorways and veins as low-pressure country roads - each needs different construction for their traffic!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
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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
Ismail Saleem
@ismailsaleem
This AQA GCSE Biology exam covers essential topics including plant biology, drug development, and the circulatory system. You'll encounter questions about plant tissues, drug testing processes, and heart structure that are fundamental to understanding how living organisms function.
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered why plants can heal themselves or how they produce the medicines we use? This section explores the fascinating world of plant tissues and their medical applications.
Tissues are groups of similar cells working together to perform specific functions - think of them as specialised teams within an organism. Plants contain stem cells in their meristematic tissue, particularly at root tips, which can develop into any type of cell the plant needs.
Many of our everyday medicines originated from plants. Aspirin, one of the world's most common painkillers, actually comes from willow bark. This connection between plants and medicine shows why understanding plant biology is so relevant to modern healthcare.
Quick Tip: Remember that meristematic tissue is where all the action happens - it's the plant's growth headquarters!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Scientists don't just randomly pick parts of plants when extracting medicines - there's proper science behind these decisions.
When extracting chemical A from deadly nightshade, scientists prefer using berries over leaves or roots for practical reasons. Berries might be easier to harvest, cause less damage to the plant, or simply be more accessible than digging up roots.
The data shows that whilst leaves contain more chemical A than berries (1.2g vs 0.7g per 100g), there are other factors to consider. Sustainable harvesting practices often influence which plant parts are used for drug extraction.
Real-World Connection: This is exactly how pharmaceutical companies decide which parts of plants to use - balancing chemical content with practical harvesting concerns!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Maths isn't just for maths lessons - it's crucial for understanding biological processes and making real-world calculations.
When plants develop chlorosis (yellowing leaves), their chemical composition changes. If healthy leaves contain a certain amount of a compound, diseased leaves will contain less. You'll need to calculate these differences using percentages and unit conversions.
Chlorosis typically occurs due to nutrient deficiencies, particularly lack of magnesium or iron, which are essential for chlorophyll production. Without enough chlorophyll, leaves can't photosynthesise effectively and turn yellow.
Exam Strategy: Always show your working clearly in calculations - you can still earn marks even if your final answer isn't quite right!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Before any medicine reaches your local pharmacy, it goes through rigorous testing - and there are excellent reasons why this process exists.
Clinical trials are essential because they test for safety and effectiveness in real humans. Drugs might work brilliantly in laboratory conditions but cause unexpected side effects in people, or simply not work as expected in the human body.
Bias in scientific reporting is a real problem, especially online. Reports might be biased because companies want to sell products, researchers have financial interests, or people simply want to promote their beliefs rather than facts.
The gold standard for ensuring scientific claims are valid is peer review - where other experts examine and critique research before it's published.
Critical Thinking: Always question the source when you read health claims online - peer-reviewed scientific journals are far more reliable than social media posts!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your heart is essentially a sophisticated pump system, and understanding its structure helps explain how blood circulates around your body.
The heart has four chambers working in perfect coordination. The left atrium receives oxygenated blood from the lungs, whilst the right ventricle pumps deoxygenated blood to the lungs for refreshing.
The pacemaker (sinoatrial node) is located in the right atrium and acts like your heart's natural timer, setting the rhythm for each heartbeat. This small group of cells ensures your heart beats regularly without you having to think about it.
Memory Trick: Remember "right to lungs" - the right side of your heart deals with sending blood to your lungs for oxygen!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Arteries and veins have distinctly different structures because they perform different jobs in your circulatory system.
Arteries have thicker walls with more muscle tissue and elastic tissue because they must withstand high pressure as blood is pumped directly from the heart. Veins have thinner walls and contain valves to prevent backflow, since blood pressure is much lower on the return journey.
The pacemaker located in the right atrium controls your resting heart rate automatically. This natural pacemaker ensures your heart maintains a steady rhythm without conscious control.
Understanding Tip: Think of arteries as high-pressure motorways and veins as low-pressure country roads - each needs different construction for their traffic!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
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
Sociology