Cells are the basic building blocks of all living things... Show more
Science26 views·Updated May 31, 2026·3 pagesJunior Cert Science: Detailed Cell Notes
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Lily Burke@lilyburke
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The Animal Cell
Every part of your body is made up of animal cells - from your skin to your brain! These microscopic units contain several important parts called organelles that work together like a well-organised team.
The cell membrane acts like a bouncer at a club, deciding what gets in and out of the cell. It's mostly made of fat and typically lets small things like water pass through whilst blocking larger, harmful substances.
Inside the cell, you'll find the cytoplasm - a watery mixture containing salt, glucose, and other nutrients that organelles float around in. The nucleus is like the cell's control centre, containing chromosomes made of DNA that tell the cell exactly what to do.
The mitochondrion (plural: mitochondria) is known as the cell's powerhouse because it's where respiration happens - food reacts with oxygen to release energy for everything you do. Meanwhile, ribosomes are the protein factories, making important substances like the hormone insulin.
Quick Tip: Remember "MRSGREN" - all living things need energy, and that's exactly what mitochondria provide through respiration!
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The Plant Cell
Plant cells are similar to animal cells but have some extra features that help them survive and make their own food. These additional parts make plants completely self-sufficient!
The cell wall is made of cellulose (the same stuff that gives you fibre in your diet) and provides incredible strength and protection - much stronger than just a cell membrane alone. Think of it as armour around the cell.
Vacuoles are storage spaces within the cytoplasm where plants keep food and water. They're much larger in plant cells than in animal cells because plants need to store the food they make.
The most important difference is chloroplasts - these contain chlorophyll, the green chemical that captures light energy. This is where photosynthesis happens, allowing plants to make their own food using sunlight, water, and carbon dioxide.
Remember: Plants still have mitochondria and ribosomes just like animal cells - they need energy and proteins too!
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The Light Microscope
Without microscopes, we'd never be able to see these amazing cells! The light microscope is your gateway to exploring the microscopic world that exists all around you.
A microscope has several key parts working together. The eyepiece is where you look through, whilst objective lenses provide different levels of magnification. The stage holds your specimen steady under the light.
Coarse focus gets you roughly in focus quickly, then fine focus gives you that crystal-clear image you need. The iris diaphragm controls how much light shines through your specimen - too much light washes everything out, too little makes it too dark to see properly.
Learning to use a microscope properly takes practice, but once you master it, you'll be amazed at the incredible detail you can observe in everyday objects like onion skin or your own cheek cells.
Pro Tip: Always start with the lowest magnification objective lens and work your way up - it's much easier to find your specimen this way!
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Science26 views·Updated May 31, 2026·3 pagesJunior Cert Science: Detailed Cell Notes
L
Lily Burke@lilyburke
Cells are the basic building blocks of all living things - they're like tiny factories that keep us alive! Understanding how animal and plant cells work will help you grasp how your own body functions and how plants make their... Show more
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The Animal Cell
Every part of your body is made up of animal cells - from your skin to your brain! These microscopic units contain several important parts called organelles that work together like a well-organised team.
The cell membrane acts like a bouncer at a club, deciding what gets in and out of the cell. It's mostly made of fat and typically lets small things like water pass through whilst blocking larger, harmful substances.
Inside the cell, you'll find the cytoplasm - a watery mixture containing salt, glucose, and other nutrients that organelles float around in. The nucleus is like the cell's control centre, containing chromosomes made of DNA that tell the cell exactly what to do.
The mitochondrion (plural: mitochondria) is known as the cell's powerhouse because it's where respiration happens - food reacts with oxygen to release energy for everything you do. Meanwhile, ribosomes are the protein factories, making important substances like the hormone insulin.
Quick Tip: Remember "MRSGREN" - all living things need energy, and that's exactly what mitochondria provide through respiration!
2
of 3Sign up to see the content. It's free!
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The Plant Cell
Plant cells are similar to animal cells but have some extra features that help them survive and make their own food. These additional parts make plants completely self-sufficient!
The cell wall is made of cellulose (the same stuff that gives you fibre in your diet) and provides incredible strength and protection - much stronger than just a cell membrane alone. Think of it as armour around the cell.
Vacuoles are storage spaces within the cytoplasm where plants keep food and water. They're much larger in plant cells than in animal cells because plants need to store the food they make.
The most important difference is chloroplasts - these contain chlorophyll, the green chemical that captures light energy. This is where photosynthesis happens, allowing plants to make their own food using sunlight, water, and carbon dioxide.
Remember: Plants still have mitochondria and ribosomes just like animal cells - they need energy and proteins too!
3
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
The Light Microscope
Without microscopes, we'd never be able to see these amazing cells! The light microscope is your gateway to exploring the microscopic world that exists all around you.
A microscope has several key parts working together. The eyepiece is where you look through, whilst objective lenses provide different levels of magnification. The stage holds your specimen steady under the light.
Coarse focus gets you roughly in focus quickly, then fine focus gives you that crystal-clear image you need. The iris diaphragm controls how much light shines through your specimen - too much light washes everything out, too little makes it too dark to see properly.
Learning to use a microscope properly takes practice, but once you master it, you'll be amazed at the incredible detail you can observe in everyday objects like onion skin or your own cheek cells.
Pro Tip: Always start with the lowest magnification objective lens and work your way up - it's much easier to find your specimen this way!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the 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 in Science
6Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user