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
Show all topics
Biology
7 Dec 2025
269
3 pages
hayaa @hayaa_tset
Understanding how cells work starts with being able to see them properly - and that's where microscopy comes... Show more
Ever wondered how scientists can see things thousands of times smaller than what your eyes can detect? Magnification shows how many times larger an object appears, whilst resolution determines how clearly you can distinguish between two separate objects.
Light microscopes are your basic classroom microscopes with a maximum magnification of x1500 and resolution of 0.2 micrometres. They're perfect for observing living cells and basic structures. Laser scanning confocal microscopes use fluorescent dyes to build images layer by layer, though they're quite slow and can distort what you're seeing.
For serious detail, electron microscopes are game-changers. Scanning electron microscopes (SEM) bounce electrons off surfaces to create stunning 3D images at x100,000 magnification. Transmission electron microscopes (TEM) fire electrons through specimens for incredible 2D detail at x500,000 magnification and 0.5nm resolution.
Quick Tip Remember that electron microscopes can't show living cells or natural colours - specimens must be dead and specially prepared.
Think of cells as incredibly organised factories where every component has a specific job. The nucleus acts as the control centre, surrounded by a nuclear envelope with pores that control molecular traffic. Inside, you'll find chromatin (which becomes chromosomes) and the nucleolus where ribosomes are made.
Mitochondria are the cell's powerhouses - these oval organelles have inner folds called cristae and contain a fluid matrix packed with enzymes for aerobic respiration and ATP production. Meanwhile, ribosomes are the protein-making factories scattered throughout the cell.
The endoplasmic reticulum comes in two varieties rough ER (studded with ribosomes for protein processing) and smooth ER (for lipid production). The Golgi apparatus acts like a postal service, modifying and packaging proteins before shipping them out in vesicles.
Lysosomes are the cell's recycling centres, containing enzymes that break down waste and harmful pathogens. The cytoskeleton provides structural support through microfilaments, microtubules, and intermediate filaments - think of it as the cell's internal scaffolding.
Remember Plant cells have additional structures like chloroplasts (for photosynthesis) and cell walls made of cellulose for extra support.
Ever wondered how cells make and deliver proteins exactly where they're needed? It's like an incredibly efficient assembly line that never stops working.
The process starts when DNA in the nucleus copies instructions into mRNA, which travels through nuclear pores to attach to ribosomes. These ribosomes then manufacture the required proteins based on the genetic instructions.
Proteins made on the rough ER get folded and packaged before being transported via vesicles to the Golgi apparatus. Here's where the magic happens - the Golgi modifies these proteins by adding things like sugar molecules, essentially customising them for their final destination.
Finally, the Golgi packages these modified proteins into new vesicles that transport them around the cell or even outside it. This entire system ensures every protein ends up exactly where it's supposed to be, when it's supposed to be there.
Key Point This transport system is essential for hormone production, enzyme delivery, and maintaining cellular functions - it's basically the cell's internal courier service.
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.
4
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the key differences between eukaryotic and prokaryotic cells, including animal, plant, and bacterial cell structures. This summary covers essential components such as the nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, cell wall, vacuoles, plasmid DNA, and flagella, along with their functions in cellular processes.
BiologyExplore the five main kingdoms of life, focusing on the characteristics of eukaryotic cells, including protists, fungi, and their classification. This summary covers key concepts such as multicellularity, heterotrophy, and autotrophy, providing a clear overview for students studying biological classification.
BiologyExplore the structure and function of key cell organelles in this detailed summary. Understand the roles of the nucleus, mitochondria, ribosomes, and more in cellular processes. Ideal for A-Level Biology students seeking to grasp essential concepts in cell biology.
BiologyExplore the key differences and similarities between animal and plant cells, including their unique subcellular structures such as the cell wall, chloroplasts, and organelles like mitochondria and ribosomes. This summary provides a clear overview of cellular functions and shapes, essential for understanding basic biology concepts.
BiologyExplore the essential components of cells and their functions in this detailed summary. Key topics include the nucleus, mitochondria, chloroplasts, Golgi apparatus, endoplasmic reticulum, lysosomes, ribosomes, and cell walls. Ideal for A-level Biology students, this resource provides clear explanations and diagrams to enhance understanding of cellular structures and processes.
BiologyExplore the distinctions between prokaryotic and eukaryotic cells across the five kingdoms: Prokaryotae, Protoctista, Fungi, Plantae, and Animalia. This summary covers cellular structures, functions, and key characteristics, including ribosome types, DNA structure, and nutritional modes. Ideal for students studying cellular biology and taxonomy.
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
hayaa
@hayaa_tset
Understanding how cells work starts with being able to see them properly - and that's where microscopy comes in. Different types of microscopes reveal different details about cell structure, from basic shapes to incredibly tiny organelles that keep cells alive.
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Join milions of students
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Ever wondered how scientists can see things thousands of times smaller than what your eyes can detect? Magnification shows how many times larger an object appears, whilst resolution determines how clearly you can distinguish between two separate objects.
Light microscopes are your basic classroom microscopes with a maximum magnification of x1500 and resolution of 0.2 micrometres. They're perfect for observing living cells and basic structures. Laser scanning confocal microscopes use fluorescent dyes to build images layer by layer, though they're quite slow and can distort what you're seeing.
For serious detail, electron microscopes are game-changers. Scanning electron microscopes (SEM) bounce electrons off surfaces to create stunning 3D images at x100,000 magnification. Transmission electron microscopes (TEM) fire electrons through specimens for incredible 2D detail at x500,000 magnification and 0.5nm resolution.
Quick Tip: Remember that electron microscopes can't show living cells or natural colours - specimens must be dead and specially prepared.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think of cells as incredibly organised factories where every component has a specific job. The nucleus acts as the control centre, surrounded by a nuclear envelope with pores that control molecular traffic. Inside, you'll find chromatin (which becomes chromosomes) and the nucleolus where ribosomes are made.
Mitochondria are the cell's powerhouses - these oval organelles have inner folds called cristae and contain a fluid matrix packed with enzymes for aerobic respiration and ATP production. Meanwhile, ribosomes are the protein-making factories scattered throughout the cell.
The endoplasmic reticulum comes in two varieties: rough ER (studded with ribosomes for protein processing) and smooth ER (for lipid production). The Golgi apparatus acts like a postal service, modifying and packaging proteins before shipping them out in vesicles.
Lysosomes are the cell's recycling centres, containing enzymes that break down waste and harmful pathogens. The cytoskeleton provides structural support through microfilaments, microtubules, and intermediate filaments - think of it as the cell's internal scaffolding.
Remember: Plant cells have additional structures like chloroplasts (for photosynthesis) and cell walls made of cellulose for extra support.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered how cells make and deliver proteins exactly where they're needed? It's like an incredibly efficient assembly line that never stops working.
The process starts when DNA in the nucleus copies instructions into mRNA, which travels through nuclear pores to attach to ribosomes. These ribosomes then manufacture the required proteins based on the genetic instructions.
Proteins made on the rough ER get folded and packaged before being transported via vesicles to the Golgi apparatus. Here's where the magic happens - the Golgi modifies these proteins by adding things like sugar molecules, essentially customising them for their final destination.
Finally, the Golgi packages these modified proteins into new vesicles that transport them around the cell or even outside it. This entire system ensures every protein ends up exactly where it's supposed to be, when it's supposed to be there.
Key Point: This transport system is essential for hormone production, enzyme delivery, and maintaining cellular functions - it's basically the cell's internal courier service.
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.
4
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the key differences between eukaryotic and prokaryotic cells, including animal, plant, and bacterial cell structures. This summary covers essential components such as the nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, cell wall, vacuoles, plasmid DNA, and flagella, along with their functions in cellular processes.
BiologyExplore the five main kingdoms of life, focusing on the characteristics of eukaryotic cells, including protists, fungi, and their classification. This summary covers key concepts such as multicellularity, heterotrophy, and autotrophy, providing a clear overview for students studying biological classification.
BiologyExplore the structure and function of key cell organelles in this detailed summary. Understand the roles of the nucleus, mitochondria, ribosomes, and more in cellular processes. Ideal for A-Level Biology students seeking to grasp essential concepts in cell biology.
BiologyExplore the key differences and similarities between animal and plant cells, including their unique subcellular structures such as the cell wall, chloroplasts, and organelles like mitochondria and ribosomes. This summary provides a clear overview of cellular functions and shapes, essential for understanding basic biology concepts.
BiologyExplore the essential components of cells and their functions in this detailed summary. Key topics include the nucleus, mitochondria, chloroplasts, Golgi apparatus, endoplasmic reticulum, lysosomes, ribosomes, and cell walls. Ideal for A-level Biology students, this resource provides clear explanations and diagrams to enhance understanding of cellular structures and processes.
BiologyExplore the distinctions between prokaryotic and eukaryotic cells across the five kingdoms: Prokaryotae, Protoctista, Fungi, Plantae, and Animalia. This summary covers cellular structures, functions, and key characteristics, including ribosome types, DNA structure, and nutritional modes. Ideal for students studying cellular biology and taxonomy.
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