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GCSE AQA Biology Study Notes: Cells, Tissues, Organs
Nila Heartin
@nilaheartin_tmsl
1 / 6
Animal and Plant Cells
Your body contains trillions of cells, each one a microscopic factory working 24/7 to keep you alive. Both animal and plant cells are eukaryotes, which simply means they have their genetic material safely stored in a nucleus rather than floating around freely.
Every cell has essential parts called organelles - think of them as tiny organs with specific jobs. The nucleus acts like the cell's brain, controlling everything and storing DNA. The cytoplasm is where most chemical reactions happen, whilst mitochondria are the powerhouses that release energy through respiration.
Plant cells have some extra features that animal cells don't need. The cell wall provides strength and structure, chloroplasts contain the green pigment chlorophyll for photosynthesis, and a large vacuole filled with cell sap helps maintain the plant's shape.
Key Point: Remember that structure always matches function - each organelle is perfectly designed for its specific job in the cell.
Prokaryotes and Bacteria
Unlike the complex cells in your body, prokaryotes are much simpler organisms that don't have a proper nucleus. Instead, their DNA just floats around freely in the cell, though it's still clumped together in one area.
Most prokaryotes are bacteria, and they're absolutely everywhere - in your gut helping with digestion, in yoghurt, even in extreme environments like hot springs. Don't let their simplicity fool you though; bacteria are incredibly successful and have survived for billions of years.
Bacterial cells have some unique features you won't find in human cells. The flagellum works like a tiny propeller for movement, whilst pili help bacteria stick to surfaces. Plasmids are small loops of extra DNA that bacteria can share with each other.
Key Point: Size matters in biology - bacteria are bigger than viruses but much smaller than the cells in your body.
Using Microscopes
Before microscopes were invented in the 17th century, nobody knew cells existed because they're far too small to see with your naked eye. Now you can explore this hidden world yourself with some simple techniques.
To observe onion cells, slice the onion extremely thinly so light can pass through, then add a drop of iodine to make the cells more visible. For cheek cells, gently swab the inside of your mouth and add methylene blue dye to highlight the structures.
Magnification tells you how many times bigger the image appears compared to the real object. To calculate total magnification, multiply the eyepiece lens power by the objective lens power. Working backwards from magnification lets you figure out the actual size of what you're observing.
Key Point: Always start with the lowest magnification and work your way up - it's much easier to find your specimen this way.
Light vs Electron Microscopes
Light microscopes are the workhorses of school biology labs, and for good reason. They're affordable, portable, and easy to use, plus you can observe living specimens in full colour. Perfect for getting started with cell biology.
Electron microscopes are the high-tech giants that reveal incredible detail and can magnify objects hundreds of thousands of times. They can even create 3D images, but they're expensive, huge, and require specimens to be dead and in a vacuum.
Understanding standard form becomes crucial when dealing with microscopic measurements. Numbers like 15,000,000 become much easier to handle as 1.5 × 10⁷. Remember: positive powers make numbers bigger, negative powers make them smaller.
Key Point: Choose your microscope based on what you need - light for live observations, electron for maximum detail and magnification.
Specialised Cells
Your body contains millions of different cells, each one perfectly adapted for its specific job. Sperm cells have long tails for swimming and lots of mitochondria for energy, whilst nerve cells are incredibly long to transmit messages across your body quickly.
Root hair cells in plants increase surface area to absorb more water from soil. Muscle cells contain special protein fibres that contract to create movement. Each cell's structure directly relates to its function.
The process of differentiation is how unspecialised stem cells become these specialist cells. In early embryos, stem cells can become any type of cell in the body. Most animal cells lose this flexibility as they mature, but plant cells often keep it throughout their lives.
Key Point: Stem cells are like biological blank slates - they have the potential to become any specialised cell type the body needs.
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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
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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
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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
GCSE AQA Biology Study Notes: Cells, Tissues, Organs
Nila Heartin
@nilaheartin_tmsl
Ever wondered what makes up every living thing around you? From the tiniest bacteria to massive trees, everything is built from cells - the building blocks of life. Understanding how these microscopic structures work and organise themselves is key to... Show more
Animal and Plant Cells
Your body contains trillions of cells, each one a microscopic factory working 24/7 to keep you alive. Both animal and plant cells are eukaryotes, which simply means they have their genetic material safely stored in a nucleus rather than floating around freely.
Every cell has essential parts called organelles - think of them as tiny organs with specific jobs. The nucleus acts like the cell's brain, controlling everything and storing DNA. The cytoplasm is where most chemical reactions happen, whilst mitochondria are the powerhouses that release energy through respiration.
Plant cells have some extra features that animal cells don't need. The cell wall provides strength and structure, chloroplasts contain the green pigment chlorophyll for photosynthesis, and a large vacuole filled with cell sap helps maintain the plant's shape.
Key Point: Remember that structure always matches function - each organelle is perfectly designed for its specific job in the cell.
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Prokaryotes and Bacteria
Unlike the complex cells in your body, prokaryotes are much simpler organisms that don't have a proper nucleus. Instead, their DNA just floats around freely in the cell, though it's still clumped together in one area.
Most prokaryotes are bacteria, and they're absolutely everywhere - in your gut helping with digestion, in yoghurt, even in extreme environments like hot springs. Don't let their simplicity fool you though; bacteria are incredibly successful and have survived for billions of years.
Bacterial cells have some unique features you won't find in human cells. The flagellum works like a tiny propeller for movement, whilst pili help bacteria stick to surfaces. Plasmids are small loops of extra DNA that bacteria can share with each other.
Key Point: Size matters in biology - bacteria are bigger than viruses but much smaller than the cells in your body.
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Using Microscopes
Before microscopes were invented in the 17th century, nobody knew cells existed because they're far too small to see with your naked eye. Now you can explore this hidden world yourself with some simple techniques.
To observe onion cells, slice the onion extremely thinly so light can pass through, then add a drop of iodine to make the cells more visible. For cheek cells, gently swab the inside of your mouth and add methylene blue dye to highlight the structures.
Magnification tells you how many times bigger the image appears compared to the real object. To calculate total magnification, multiply the eyepiece lens power by the objective lens power. Working backwards from magnification lets you figure out the actual size of what you're observing.
Key Point: Always start with the lowest magnification and work your way up - it's much easier to find your specimen this way.
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Light vs Electron Microscopes
Light microscopes are the workhorses of school biology labs, and for good reason. They're affordable, portable, and easy to use, plus you can observe living specimens in full colour. Perfect for getting started with cell biology.
Electron microscopes are the high-tech giants that reveal incredible detail and can magnify objects hundreds of thousands of times. They can even create 3D images, but they're expensive, huge, and require specimens to be dead and in a vacuum.
Understanding standard form becomes crucial when dealing with microscopic measurements. Numbers like 15,000,000 become much easier to handle as 1.5 × 10⁷. Remember: positive powers make numbers bigger, negative powers make them smaller.
Key Point: Choose your microscope based on what you need - light for live observations, electron for maximum detail and magnification.
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Specialised Cells
Your body contains millions of different cells, each one perfectly adapted for its specific job. Sperm cells have long tails for swimming and lots of mitochondria for energy, whilst nerve cells are incredibly long to transmit messages across your body quickly.
Root hair cells in plants increase surface area to absorb more water from soil. Muscle cells contain special protein fibres that contract to create movement. Each cell's structure directly relates to its function.
The process of differentiation is how unspecialised stem cells become these specialist cells. In early embryos, stem cells can become any type of cell in the body. Most animal cells lose this flexibility as they mature, but plant cells often keep it throughout their lives.
Key Point: Stem cells are like biological blank slates - they have the potential to become any specialised cell type the body needs.
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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