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Classic Dramatic Literature
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Human Organ Systems
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Nazi Germany and Holocaust 1933-1945
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84
•
24 Dec 2025
•
evie
@eviekatherine09
Understanding how substances move around living organisms is essential for... Show more
Think of diffusion as nature's way of spreading things out evenly - just like how your perfume fills a room without you doing anything! Diffusion happens when particles move from areas where there's loads of them (high concentration) to areas where there aren't many (low concentration).
This process works faster when it's warmer because particles have more energy to zoom about. The bigger the difference in concentration between two areas, the quicker diffusion happens.
Your body has some brilliant adaptations for gas exchange. Alveoli in your lungs have thin walls and a massive surface area, whilst villi in your intestines are covered in millions of tiny projections. Fish gills work similarly, with blood flowing in the opposite direction to water for maximum efficiency.
Quick Tip: Remember that all gas exchange surfaces share three key features - they're thin, have a large surface area, and maintain good blood supply!
You'll definitely need to know these food tests for your exams, so let's break them down simply! Start by grinding your food sample with distilled water using a mortar and pestle, then filter out the lumps.
For starch, add iodine solution to your food sample - it'll turn blue-black if starch is present, staying orange if there isn't any. Sugar testing uses Benedict's solution (which is blue) and needs heating - you'll see colour changes from blue to green, yellow, orange, or brick red depending on sugar concentration.
Protein tests use Biuret solution that starts blue and turns pink or purple when proteins are detected. For lipids, you don't filter the solution - just add ethanol and distilled water, then shake gently.
Exam Tip: Make sure you can describe the colour changes for each test - examiners love asking about the specific colours you'll observe!
Your digestive system is basically a brilliant food processing factory that breaks down complex meals into simple nutrients your body can actually use. It all starts in your mouth where salivary glands release amylase enzyme to begin breaking down starch.
Your stomach churns food whilst releasing protease enzymes and hydrochloric acid that kills harmful bacteria. The liver makes bile (stored in the gall bladder) which neutralises stomach acid and helps digest fats.
The pancreas is like a chemical factory, producing three major enzymes: amylase, lipase, and protease. Finally, your small intestine absorbs all the digested nutrients into your bloodstream, whilst the large intestine absorbs water and minerals.
Remember: The digestive system's main job is creating a massive surface area for maximum nutrient absorption - that's why the small intestine is so long and folded!
Photosynthesis is how plants make their own food using just sunlight, carbon dioxide, and water - pretty amazing really! The equation you need to memorise is: carbon dioxide + water → glucose + oxygen (with light energy and chlorophyll needed).
This endothermic reaction happens mainly in leaf cells, particularly in the palisade and spongy mesophyll layers where chlorophyll captures light energy. Carbon dioxide enters through tiny holes called stomata, whilst water travels up from the roots through xylem tubes.
The glucose produced gets used for energy, growth, and making other important molecules like cellulose and starch. Oxygen is released as a waste product, which is brilliant news for us since we need it to breathe!
Key Point: During daylight hours, plants produce more oxygen than they use for respiration, making them essential for maintaining Earth's oxygen levels.
Knowing how to use a light microscope properly is a required practical skill you'll need for your GCSE. Start with the lowest power objective lens positioned just above the slide, then use the coarse focusing dial to bring cells into view.
The magnification formula is dead simple: magnification = image size ÷ actual size. You can rearrange this to find any missing value, so make sure you're comfortable with basic maths rearrangement.
Light microscopes are cheaper and easier to use but have limited magnification. Electron microscopes offer much higher magnification and resolution but cost loads more and aren't portable.
Practical Tip: Always start with low power to find your specimen, then switch to high power and use the fine focus dial for crystal-clear images!
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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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
evie
@eviekatherine09
Understanding how substances move around living organisms is essential for GCSE Biology success. From photosynthesis in plants to digestion in humans, these processes keep all life forms functioning properly.
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Think of diffusion as nature's way of spreading things out evenly - just like how your perfume fills a room without you doing anything! Diffusion happens when particles move from areas where there's loads of them (high concentration) to areas where there aren't many (low concentration).
This process works faster when it's warmer because particles have more energy to zoom about. The bigger the difference in concentration between two areas, the quicker diffusion happens.
Your body has some brilliant adaptations for gas exchange. Alveoli in your lungs have thin walls and a massive surface area, whilst villi in your intestines are covered in millions of tiny projections. Fish gills work similarly, with blood flowing in the opposite direction to water for maximum efficiency.
Quick Tip: Remember that all gas exchange surfaces share three key features - they're thin, have a large surface area, and maintain good blood supply!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
You'll definitely need to know these food tests for your exams, so let's break them down simply! Start by grinding your food sample with distilled water using a mortar and pestle, then filter out the lumps.
For starch, add iodine solution to your food sample - it'll turn blue-black if starch is present, staying orange if there isn't any. Sugar testing uses Benedict's solution (which is blue) and needs heating - you'll see colour changes from blue to green, yellow, orange, or brick red depending on sugar concentration.
Protein tests use Biuret solution that starts blue and turns pink or purple when proteins are detected. For lipids, you don't filter the solution - just add ethanol and distilled water, then shake gently.
Exam Tip: Make sure you can describe the colour changes for each test - examiners love asking about the specific colours you'll observe!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your digestive system is basically a brilliant food processing factory that breaks down complex meals into simple nutrients your body can actually use. It all starts in your mouth where salivary glands release amylase enzyme to begin breaking down starch.
Your stomach churns food whilst releasing protease enzymes and hydrochloric acid that kills harmful bacteria. The liver makes bile (stored in the gall bladder) which neutralises stomach acid and helps digest fats.
The pancreas is like a chemical factory, producing three major enzymes: amylase, lipase, and protease. Finally, your small intestine absorbs all the digested nutrients into your bloodstream, whilst the large intestine absorbs water and minerals.
Remember: The digestive system's main job is creating a massive surface area for maximum nutrient absorption - that's why the small intestine is so long and folded!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Photosynthesis is how plants make their own food using just sunlight, carbon dioxide, and water - pretty amazing really! The equation you need to memorise is: carbon dioxide + water → glucose + oxygen (with light energy and chlorophyll needed).
This endothermic reaction happens mainly in leaf cells, particularly in the palisade and spongy mesophyll layers where chlorophyll captures light energy. Carbon dioxide enters through tiny holes called stomata, whilst water travels up from the roots through xylem tubes.
The glucose produced gets used for energy, growth, and making other important molecules like cellulose and starch. Oxygen is released as a waste product, which is brilliant news for us since we need it to breathe!
Key Point: During daylight hours, plants produce more oxygen than they use for respiration, making them essential for maintaining Earth's oxygen levels.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Knowing how to use a light microscope properly is a required practical skill you'll need for your GCSE. Start with the lowest power objective lens positioned just above the slide, then use the coarse focusing dial to bring cells into view.
The magnification formula is dead simple: magnification = image size ÷ actual size. You can rearrange this to find any missing value, so make sure you're comfortable with basic maths rearrangement.
Light microscopes are cheaper and easier to use but have limited magnification. Electron microscopes offer much higher magnification and resolution but cost loads more and aren't portable.
Practical Tip: Always start with low power to find your specimen, then switch to high power and use the fine focus dial for crystal-clear images!
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
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