Cells are the building blocks of all living things! They're... Show more
Biology28 views·Updated May 22, 2026·3 pagesExploring Ecosystems: Middle School Life Science Unit 7 Lesson 2
A
Aaron Jackson@aaronjackson_kbwj
1 / 3
1
of 3
The Basics of Cells
Cells are the basic units of life that make up every living organism. According to cell theory, all living things are made of cells, cells are the fundamental units of structure and function, and all cells come from other cells. There are two main types of cells: prokaryotic cells (simple cells without a nucleus) and eukaryotic cells (complex cells with a nucleus and specialized parts).
Your body's cells have specialized structures called organelles that perform specific jobs. The nucleus acts like the cell's brain, containing DNA and controlling all cellular activities. Surrounding each cell is the cell membrane, a flexible barrier that decides what gets in and out of the cell. Inside the cell is a jelly-like fluid called cytoplasm where organelles float.
Some key organelles include mitochondria, often called the powerhouse of the cell because they produce energy through cellular respiration. The endoplasmic reticulum (ER) is a network of membranes that makes proteins and lipids, while the Golgi apparatus packages and ships these materials to where they need to go.
Did You Know? Your body contains about 37.2 trillion cells, but they're constantly being replaced. Most of the cells you had as a child aren't the ones you have now!
2
of 3
More Cell Parts and Processes
Cells contain additional important structures that keep them functioning. Lysosomes are like the cell's cleanup crew, containing enzymes that break down waste and cellular debris. Vacuoles are storage sacs that can hold water, nutrients, or waste. Plant cells have special organelles called chloroplasts that capture sunlight for photosynthesis, and a rigid cell wall outside their cell membrane for extra protection and support.
Cells perform amazing processes to keep organisms alive. During cellular respiration, cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. Plants use photosynthesis to do the opposite—they take sunlight, carbon dioxide, and water to make glucose and oxygen. That's how plants make their own food and provide oxygen for animals to breathe!
Cells reproduce through cell division to create new cells. Mitosis is the type of cell division that creates identical body cells with the full number of chromosomes. Meiosis is a special type of cell division that creates sex cells (like eggs and sperm) with half the usual number of chromosomes.
Think About It: Every second, about 50 million of your cells die and get replaced by new ones through cell division. This process happens constantly throughout your life!
3
of 3
Key Cell Vocabulary
Understanding cells means knowing the language of biology! Make sure you're familiar with these important terms: cell (the basic unit of life) and cell theory (the fundamental concept about cells). Remember the difference between prokaryotic cells (without nucleus) and eukaryotic cells (with nucleus and organelles).
Cell structures are crucial to know, including the nucleus (control center), cell membrane (protective barrier), and cytoplasm . Other important organelles include mitochondria (energy producers), endoplasmic reticulum (protein factory), Golgi apparatus (packaging center), lysosomes (digestive sacs), vacuoles (storage areas), chloroplasts (photosynthesis sites in plants), and cell wall (outer plant cell protection).
Don't forget the key processes: cellular respiration (making energy from glucose), photosynthesis (making glucose from sunlight), cell division (making new cells), mitosis (body cell division), and meiosis (sex cell division). These terms will come up often in your biology class!
Study Tip: Make flashcards for these key terms and review them regularly. Try drawing and labeling a cell to help remember where each organelle is located and what it does!
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.
Similar Content
Most popular content in Biology
9Most 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
Biology28 views·Updated May 22, 2026·3 pagesExploring Ecosystems: Middle School Life Science Unit 7 Lesson 2
A
Aaron Jackson@aaronjackson_kbwj
Cells are the building blocks of all living things! They're tiny but packed with parts that work together to keep organisms alive. Understanding how cells work helps us understand how our bodies function and how all living things are connected.
1
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
The Basics of Cells
Cells are the basic units of life that make up every living organism. According to cell theory, all living things are made of cells, cells are the fundamental units of structure and function, and all cells come from other cells. There are two main types of cells: prokaryotic cells (simple cells without a nucleus) and eukaryotic cells (complex cells with a nucleus and specialized parts).
Your body's cells have specialized structures called organelles that perform specific jobs. The nucleus acts like the cell's brain, containing DNA and controlling all cellular activities. Surrounding each cell is the cell membrane, a flexible barrier that decides what gets in and out of the cell. Inside the cell is a jelly-like fluid called cytoplasm where organelles float.
Some key organelles include mitochondria, often called the powerhouse of the cell because they produce energy through cellular respiration. The endoplasmic reticulum (ER) is a network of membranes that makes proteins and lipids, while the Golgi apparatus packages and ships these materials to where they need to go.
Did You Know? Your body contains about 37.2 trillion cells, but they're constantly being replaced. Most of the cells you had as a child aren't the ones you have now!
2
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
More Cell Parts and Processes
Cells contain additional important structures that keep them functioning. Lysosomes are like the cell's cleanup crew, containing enzymes that break down waste and cellular debris. Vacuoles are storage sacs that can hold water, nutrients, or waste. Plant cells have special organelles called chloroplasts that capture sunlight for photosynthesis, and a rigid cell wall outside their cell membrane for extra protection and support.
Cells perform amazing processes to keep organisms alive. During cellular respiration, cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. Plants use photosynthesis to do the opposite—they take sunlight, carbon dioxide, and water to make glucose and oxygen. That's how plants make their own food and provide oxygen for animals to breathe!
Cells reproduce through cell division to create new cells. Mitosis is the type of cell division that creates identical body cells with the full number of chromosomes. Meiosis is a special type of cell division that creates sex cells (like eggs and sperm) with half the usual number of chromosomes.
Think About It: Every second, about 50 million of your cells die and get replaced by new ones through cell division. This process happens constantly throughout your life!
3
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Key Cell Vocabulary
Understanding cells means knowing the language of biology! Make sure you're familiar with these important terms: cell (the basic unit of life) and cell theory (the fundamental concept about cells). Remember the difference between prokaryotic cells (without nucleus) and eukaryotic cells (with nucleus and organelles).
Cell structures are crucial to know, including the nucleus (control center), cell membrane (protective barrier), and cytoplasm . Other important organelles include mitochondria (energy producers), endoplasmic reticulum (protein factory), Golgi apparatus (packaging center), lysosomes (digestive sacs), vacuoles (storage areas), chloroplasts (photosynthesis sites in plants), and cell wall (outer plant cell protection).
Don't forget the key processes: cellular respiration (making energy from glucose), photosynthesis (making glucose from sunlight), cell division (making new cells), mitosis (body cell division), and meiosis (sex cell division). These terms will come up often in your biology class!
Study Tip: Make flashcards for these key terms and review them regularly. Try drawing and labeling a cell to help remember where each organelle is located and what it does!
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.
Similar Content
Most popular content in Biology
9Most 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