What Are Cells Made Of?

🕐 6 min 5 sec 👦 Ages 9–12 🌍 English
Join Owlo and Koko as they explore the fascinating world of cells and discover what makes up all living things!
Understand the basic structure of cells Learn why cells are important for life Explore how cells function in living organisms
📖 Story Script
                    Koko:
                    Owlo, I have a question that has been stuck in my head all day. It started in science class this morning.
                
                    Owlo:
                    Oh, that sounds like a good kind of stuck. What happened in science class?
                
                    Koko:
                    Ms. Fern said that every living thing is made of cells. But I kept thinking, what even is a cell? Like, what does that actually mean?
                
                    Owlo:
                    That is one of the most fascinating questions in all of biology, Koko. I am really glad you brought it here.
                
                    Koko:
                    Do you know the answer? Because Ms. Fern moved on really fast and I did not want to look confused in front of everyone.
                
                    Owlo:
                    I do know quite a bit about cells. But I think we should head to the science lab. This topic deserves a proper look.
                
                    Owlo:
                    Here we are. Now, let me grab this microscope from the shelf. We are going to need it.
                
                    Koko:
                    That thing looks serious. Are we actually going to see cells through that?
                
                    Owlo:
                    We are indeed. But first, let me explain what a cell is. A cell is the smallest unit of life. Everything alive is made of them.
                
                    Koko:
                    Wait, so I am made of cells right now? Like, my whole body?
                
                    Owlo:
                    Every single part of you. Your skin, your blood, your brain, your bones. All of it is built from trillions of tiny cells.
                
                    Koko:
                    Trillions? That number does not even feel real. How small are they?
                
                    Owlo:
                    Most cells are so small that you cannot see them without a microscope. Thousands of them could fit on the tip of your finger.
                
                    Koko:
                    That is kind of hard to believe. They are that tiny and they are doing things?
                
                    Owlo:
                    That is the remarkable part. Cells are not just sitting there. They are working constantly. They take in food, produce energy, and repair themselves.
                
                    Koko:
                    So they are like tiny little workers inside me. That is actually really cool.
                
                    Owlo:
                    A great way to think about it. Now, there are two main types of living things when it comes to cells. Some are made of just one cell, and some are made of many.
                
                    Koko:
                    Wait, something can be alive with only one cell? What kind of creature is that?
                
                    Owlo:
                    Bacteria are a perfect example. A single bacterium is one cell, and it is completely alive. It moves, it eats, it grows, it reproduces.
                
                    Koko:
                    And then there is me, with trillions of cells all working together. That is wild.
                
                    Owlo:
                    Exactly. And here is something even more interesting. Not all your cells do the same job. Different cells have different roles.
                
                    Koko:
                    Like what? What are some of the different jobs?
                
                    Owlo:
                    Red blood cells carry oxygen around your body. Muscle cells help you move. Nerve cells send signals to your brain. Skin cells protect everything underneath.
                
                    Koko:
                    So my body is like a whole city, and each type of cell is like a different kind of worker in that city.
                
                    Owlo:
                    Koko, that is genuinely one of the best descriptions I have ever heard. That is exactly what it is like.
                
                    Koko:
                    Okay but here is what I really want to know. What does a cell actually look like on the inside?
                
                    Owlo:
                    Let me pull out this diagram from the drawer here. Every cell has a few key parts. The most important one is the nucleus.
                
                    Koko:
                    The nucleus. That sounds important. What does it do?
                
                    Owlo:
                    Think of the nucleus as the control center. It holds the instructions for everything the cell does. Those instructions are written in something called DNA.
                
                    Koko:
                    DNA! I have heard that word before. So the DNA lives inside the nucleus, inside the cell?
                
                    Owlo:
                    Precisely. And surrounding the nucleus is a jelly-like substance called cytoplasm. It fills the inside of the cell and holds everything in place.
                
                    Koko:
                    And what keeps the whole cell together? Does it have like a wall or something?
                
                    Owlo:
                    It has a cell membrane. That is a thin, flexible layer that wraps around the whole cell. It controls what goes in and what comes out.
                
                    Koko:
                    So the membrane is like the door of the city. It decides who is allowed inside.
                
                    Owlo:
                    Perfect. Now, let me set up a slide here so you can actually see some cells through the microscope.
                
                    Koko:
                    Yes, I have been waiting for this part. What are we looking at?
                
                    Owlo:
                    These are onion skin cells. They are large enough to see clearly, and they show the structure really well. Take a look.
                
                    Koko:
                    Oh wow. I can see them. They look like little boxes all lined up next to each other. Each one has a dark dot in the middle.
                
                    Owlo:
                    That dark dot is the nucleus. You are looking at real, living cells right now, Koko.
                
                    Koko:
                    I feel like I just discovered something huge. And to think these are in every onion, every plant, every animal, every person.
                
                    Owlo:
                    Life, at its most basic level, is cells. Everything starts there. Now, why don't you tell me what you learned today?
                
                    Koko:
                    Okay. So, cells are the smallest unit of life, and every living thing is made of them. Some creatures have just one cell, like bacteria, and some have trillions, like me. Inside each cell there is a nucleus that holds the DNA, which is like the instruction manual. There is cytoplasm that fills the cell, and a membrane that acts like a door controlling what goes in and out. Different cells in my body have different jobs, like carrying oxygen or sending signals to my brain. Basically, I am a walking, talking city of trillions of tiny workers. Next I want to find out how cells actually divide and make more of themselves, because that part sounds almost too amazing to be true.