Every living thing on Earth is built from tiny building... Show more
SociologySign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
7
0
Sarah May
07/12/2025
Biology
Biology topic 1
661
•
7 Dec 2025
•
Introduction to Cell Biology: Basic Concepts and Techniques
Sarah May
@sarahmay
1 / 3
Cell Biology Basics
All living organisms are made of cells, but not all cells are created equal. There are two main types you need to know about: prokaryotic cells (simple ones like bacteria) and eukaryotic cells (complex ones like yours).
Animal cells contain several key parts working together like a tiny factory. The nucleus acts as the control centre, containing your genetic material and directing all cellular activities. Mitochondria are the powerhouses where aerobic respiration happens, releasing energy for the cell to function. The cytoplasm is a gel-like substance packed with enzymes that control chemical reactions.
Plant cells have everything animal cells do, plus three extra features that make them special. Chloroplasts contain chlorophyll and carry out photosynthesis, turning sunlight into food. The cell wall made of cellulose provides extra support and strength. The large vacuole stores cell sap - a mixture of sugars and salts.
Quick tip: Remember that plant cells are like animal cells with a "survival kit" - they need extra structures because they can't move around to find food and shelter!
Bacterial cells are much simpler, lacking a proper nucleus. Instead, they have a single circular strand of DNA floating freely, plus small rings of DNA called plasmids.
Microscopy and Observation
Want to see the invisible world of cells? You'll need a microscope, and there are two main types that reveal different secrets.
Light microscopes use light and lenses to magnify specimens, letting you see individual cells and large structures like nuclei. Electron microscopes use electrons instead of light, giving much higher magnification and resolution - they can show you tiny details like ribosomes and the internal structure of mitochondria.
Resolution is crucial - it's the ability to distinguish between two separate points, giving you sharper, clearer images. Remember the key formula: Magnification = Image size ÷ Real size.
Pro tip: Always start with the lowest magnification and work your way up - you'll avoid missing your specimen entirely!
Preparing slides properly makes all the difference. Add a water droplet to your slide, place your specimen (like onion skin), add iodine solution as a stain to highlight structures, then carefully lower a cover slip to avoid air bubbles. When using the microscope, start with coarse adjustments for rough focus, then fine-tune with the fine adjustment knob.
For scientific drawings, use a sharp pencil with clear, unbroken lines. No shading or colouring - just accurate proportions and proper labels with straight lines.
Specialised Cells
Cells aren't one-size-fits-all - they're specialised for specific jobs through a process called differentiation, and their shapes perfectly match their functions.
Sperm cells are built for one mission: delivering male DNA to female DNA. They're streamlined with long tails for swimming, packed with mitochondria for energy, and have enzymes in their heads to break through egg membranes. Nerve cells carry electrical signals across your body with long extensions and branched connections forming networks.
Muscle cells are designed for contraction, with long shapes providing space to contract and loads of mitochondria for energy. These cells contain special fibres that can rapidly shorten and lengthen.
Remember: Structure always follows function - if you understand what a cell needs to do, you can usually work out why it looks the way it does!
Plant cells have their own specialists too. Root hair cells grow long projections into soil, creating massive surface areas for absorbing water and minerals. Xylem and phloem cells form transport tubes - xylem cells are hollow for carrying water upward, while phloem cells have minimal internal structures so food can flow freely in both directions.
Each specialised cell proves that form follows function - they're perfectly engineered for their specific roles in keeping organisms alive and thriving.
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.
Most popular content: Cell Differentiation
Most popular content in Biology
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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
Introduction to Cell Biology: Basic Concepts and Techniques
Sarah May
@sarahmay
Every living thing on Earth is built from tiny building blocks called cells - from the bacteria in your gut to the neurons firing in your brain right now. Understanding how cells work and how we study them is fundamental... Show more
Cell Biology Basics
All living organisms are made of cells, but not all cells are created equal. There are two main types you need to know about: prokaryotic cells (simple ones like bacteria) and eukaryotic cells (complex ones like yours).
Animal cells contain several key parts working together like a tiny factory. The nucleus acts as the control centre, containing your genetic material and directing all cellular activities. Mitochondria are the powerhouses where aerobic respiration happens, releasing energy for the cell to function. The cytoplasm is a gel-like substance packed with enzymes that control chemical reactions.
Plant cells have everything animal cells do, plus three extra features that make them special. Chloroplasts contain chlorophyll and carry out photosynthesis, turning sunlight into food. The cell wall made of cellulose provides extra support and strength. The large vacuole stores cell sap - a mixture of sugars and salts.
Quick tip: Remember that plant cells are like animal cells with a "survival kit" - they need extra structures because they can't move around to find food and shelter!
Bacterial cells are much simpler, lacking a proper nucleus. Instead, they have a single circular strand of DNA floating freely, plus small rings of DNA called plasmids.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Microscopy and Observation
Want to see the invisible world of cells? You'll need a microscope, and there are two main types that reveal different secrets.
Light microscopes use light and lenses to magnify specimens, letting you see individual cells and large structures like nuclei. Electron microscopes use electrons instead of light, giving much higher magnification and resolution - they can show you tiny details like ribosomes and the internal structure of mitochondria.
Resolution is crucial - it's the ability to distinguish between two separate points, giving you sharper, clearer images. Remember the key formula: Magnification = Image size ÷ Real size.
Pro tip: Always start with the lowest magnification and work your way up - you'll avoid missing your specimen entirely!
Preparing slides properly makes all the difference. Add a water droplet to your slide, place your specimen (like onion skin), add iodine solution as a stain to highlight structures, then carefully lower a cover slip to avoid air bubbles. When using the microscope, start with coarse adjustments for rough focus, then fine-tune with the fine adjustment knob.
For scientific drawings, use a sharp pencil with clear, unbroken lines. No shading or colouring - just accurate proportions and proper labels with straight lines.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Specialised Cells
Cells aren't one-size-fits-all - they're specialised for specific jobs through a process called differentiation, and their shapes perfectly match their functions.
Sperm cells are built for one mission: delivering male DNA to female DNA. They're streamlined with long tails for swimming, packed with mitochondria for energy, and have enzymes in their heads to break through egg membranes. Nerve cells carry electrical signals across your body with long extensions and branched connections forming networks.
Muscle cells are designed for contraction, with long shapes providing space to contract and loads of mitochondria for energy. These cells contain special fibres that can rapidly shorten and lengthen.
Remember: Structure always follows function - if you understand what a cell needs to do, you can usually work out why it looks the way it does!
Plant cells have their own specialists too. Root hair cells grow long projections into soil, creating massive surface areas for absorbing water and minerals. Xylem and phloem cells form transport tubes - xylem cells are hollow for carrying water upward, while phloem cells have minimal internal structures so food can flow freely in both directions.
Each specialised cell proves that form follows function - they're perfectly engineered for their specific roles in keeping organisms alive and thriving.
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.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Mock Exam
Quiz
Flashcards
Essay
Most popular content: Cell Differentiation
Most popular content in Biology
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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