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17 Jan 2026
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B1 Cell Biology: Mindmaps and Diagrams
hannah
@hannah_qhgof
Cell Structure and Types
Every cell contains essential structures that keep life ticking. The nucleus houses your genetic material (DNA), whilst the cytoplasm is where all the chemical reactions happen. Ribosomes build proteins, and mitochondria release energy through aerobic respiration.
There are two main cell types you need to know. Prokaryotic cells are simple, single-celled organisms like bacteria - their DNA floats freely in the cytoplasm rather than being locked in a nucleus. Eukaryotic cells are more complex and include all animal and plant cells.
Plant cells have extra bits that animal cells don't. The cell wall provides support, chloroplasts carry out photosynthesis using the green substance chlorophyll, and the vacuole contains cell sap made of sugar and salts.
Quick tip: Remember that mitochondria are the "powerhouses" of the cell - they're where energy gets released!
Microscopy and Cell Observation
Light microscopes use light and lenses to magnify specimens, letting you see individual cells and larger structures like nuclei. Electron microscopes use electrons instead of light, giving much higher magnification and resolution - basically sharper, clearer images.
When preparing slides, you'll add a stain like iodine to make structures more visible. Always start with the lowest power objective lens and use the coarse adjustment knob first, then fine-tune with the fine adjustment.
The key formula you'll need is: magnification = image size ÷ real size. This helps you calculate how much bigger something appears compared to its actual size.
Cell Differentiation and Stem Cells
Cell differentiation is how cells become specialised for specific jobs. Stem cells are undifferentiated cells that can potentially turn into any type of cell - they're found in early embryos and adult bone marrow.
Different cell types have specific adaptations: muscle cells are long with lots of mitochondria for energy, sperm cells have tails for swimming, and nerve cells are long with branched ends for carrying electrical signals.
Stem cell therapy offers exciting medical possibilities but raises ethical questions. Scientists can use stem cells to potentially treat diabetes, paralysis, and other conditions, though there are risks like viral contamination.
Cell Division and Chromosomes
Chromosomes contain your genetic material as coiled DNA molecules. Human cells have 23 pairs of chromosomes. Mitosis is how cells divide to create two identical cells for growth and repair.
The cell cycle involves DNA duplication, chromosome alignment, and separation before the cell splits completely. This process is crucial for growing, healing wounds, and replacing old cells.
Plant cells can differentiate throughout their lives, whilst most animal cells lose this ability early on. This is why plants can regrow from cuttings but animals can't regrow entire limbs.
Movement of Substances
Three key processes move substances in and out of cells. Diffusion is the movement of particles from high to low concentration - bigger concentration gradients and higher temperatures speed this up. Osmosis is specifically water movement through partially permeable membranes.
Active transport works against the concentration gradient and requires energy from respiration. Root hair cells use this to absorb minerals from soil even when there's a higher concentration inside the cell than outside.
You can investigate osmosis using potato cylinders in different sugar solutions. Mass increases show water moving in, whilst mass decreases show water moving out.
Remember: Diffusion and osmosis are passive (no energy needed), but active transport requires energy!
Gas Exchange Systems
Single-celled organisms can exchange gases directly across their membrane because they have a large surface area compared to their volume. Larger organisms need specialised exchange surfaces because their surface area to volume ratio is much smaller.
Alveoli in lungs are perfectly adapted for gas exchange with their huge surface area (75m²), thin walls, moist lining, and excellent blood supply. Similarly, villi in the small intestine have adaptations that speed up absorption of digested food.
Fish gills work differently - water flows in one direction whilst blood flows the opposite way. This counter-current flow maintains a concentration gradient, ensuring maximum oxygen transfer from water to blood.
Plant Exchange Systems
Leaves are brilliant exchange surfaces with several clever adaptations. Stomata are tiny holes on the leaf's underside that allow CO₂ in and oxygen out. Guard cells control stomata size to prevent excessive water loss.
The leaf's flattened shape increases surface area, whilst air spaces inside provide more area for gas exchange. Water vapour evaporates from cells and escapes through stomata - this is part of transpiration.
Root hair cells have long projections that increase surface area for absorbing water and minerals from soil. They use both diffusion and active transport depending on concentration gradients.
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Basil
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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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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
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THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 Knowunity AI. 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
B1 Cell Biology: Mindmaps and Diagrams
hannah
@hannah_qhgof
Cell biology is the foundation of understanding how all living things work, from tiny bacteria to complex humans. This section covers everything from basic cell structures to how substances move in and out of cells, plus how organisms exchange gases... Show more
Cell Structure and Types
Every cell contains essential structures that keep life ticking. The nucleus houses your genetic material (DNA), whilst the cytoplasm is where all the chemical reactions happen. Ribosomes build proteins, and mitochondria release energy through aerobic respiration.
There are two main cell types you need to know. Prokaryotic cells are simple, single-celled organisms like bacteria - their DNA floats freely in the cytoplasm rather than being locked in a nucleus. Eukaryotic cells are more complex and include all animal and plant cells.
Plant cells have extra bits that animal cells don't. The cell wall provides support, chloroplasts carry out photosynthesis using the green substance chlorophyll, and the vacuole contains cell sap made of sugar and salts.
Quick tip: Remember that mitochondria are the "powerhouses" of the cell - they're where energy gets released!
Microscopy and Cell Observation
Light microscopes use light and lenses to magnify specimens, letting you see individual cells and larger structures like nuclei. Electron microscopes use electrons instead of light, giving much higher magnification and resolution - basically sharper, clearer images.
When preparing slides, you'll add a stain like iodine to make structures more visible. Always start with the lowest power objective lens and use the coarse adjustment knob first, then fine-tune with the fine adjustment.
The key formula you'll need is: magnification = image size ÷ real size. This helps you calculate how much bigger something appears compared to its actual size.
Cell Differentiation and Stem Cells
Cell differentiation is how cells become specialised for specific jobs. Stem cells are undifferentiated cells that can potentially turn into any type of cell - they're found in early embryos and adult bone marrow.
Different cell types have specific adaptations: muscle cells are long with lots of mitochondria for energy, sperm cells have tails for swimming, and nerve cells are long with branched ends for carrying electrical signals.
Stem cell therapy offers exciting medical possibilities but raises ethical questions. Scientists can use stem cells to potentially treat diabetes, paralysis, and other conditions, though there are risks like viral contamination.
Cell Division and Chromosomes
Chromosomes contain your genetic material as coiled DNA molecules. Human cells have 23 pairs of chromosomes. Mitosis is how cells divide to create two identical cells for growth and repair.
The cell cycle involves DNA duplication, chromosome alignment, and separation before the cell splits completely. This process is crucial for growing, healing wounds, and replacing old cells.
Plant cells can differentiate throughout their lives, whilst most animal cells lose this ability early on. This is why plants can regrow from cuttings but animals can't regrow entire limbs.
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By signing up you accept Terms of Service and Privacy Policy
Movement of Substances
Three key processes move substances in and out of cells. Diffusion is the movement of particles from high to low concentration - bigger concentration gradients and higher temperatures speed this up. Osmosis is specifically water movement through partially permeable membranes.
Active transport works against the concentration gradient and requires energy from respiration. Root hair cells use this to absorb minerals from soil even when there's a higher concentration inside the cell than outside.
You can investigate osmosis using potato cylinders in different sugar solutions. Mass increases show water moving in, whilst mass decreases show water moving out.
Remember: Diffusion and osmosis are passive (no energy needed), but active transport requires energy!
Gas Exchange Systems
Single-celled organisms can exchange gases directly across their membrane because they have a large surface area compared to their volume. Larger organisms need specialised exchange surfaces because their surface area to volume ratio is much smaller.
Alveoli in lungs are perfectly adapted for gas exchange with their huge surface area (75m²), thin walls, moist lining, and excellent blood supply. Similarly, villi in the small intestine have adaptations that speed up absorption of digested food.
Fish gills work differently - water flows in one direction whilst blood flows the opposite way. This counter-current flow maintains a concentration gradient, ensuring maximum oxygen transfer from water to blood.
Plant Exchange Systems
Leaves are brilliant exchange surfaces with several clever adaptations. Stomata are tiny holes on the leaf's underside that allow CO₂ in and oxygen out. Guard cells control stomata size to prevent excessive water loss.
The leaf's flattened shape increases surface area, whilst air spaces inside provide more area for gas exchange. Water vapour evaporates from cells and escapes through stomata - this is part of transpiration.
Root hair cells have long projections that increase surface area for absorbing water and minerals from soil. They use both diffusion and active transport depending on concentration gradients.
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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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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
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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 Knowunity AI. 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