I know veins are made of cells, but what are cells made of? It’s very difficult to answer that — Bea, 4 years old
That’s a great question, Bea!
The human body is like a big puzzle, but with billions of tiny pieces called cells. Our cells come in different shapes and sizes. Together, they make up every part of our body, from our veins to our brain.
Our cells are really, really small. For example, look at how thin a single strand of hair is. Although it is so thin, nearly 20 cells could fit in it. That’s how they are small.
Scientists have discovered that cells are made up of different building blocks that we call molecules, like water, as well as other types like proteins, fats, and DNA.
Just like our body, which has different parts that all work together, our cells also have different parts. Let’s take a closer look.
cells have skin
The outer skin of a cell is called the plasma diaphragm. It is made up mainly of molecules called fats. This skin forms a bubble around the outside of the entire cell and holds it together.
Plants also have cells. But plant cells have an extra layer of skin called cell membran which is strong and hard, not soft like a bubble, which is why plants like trees can grow so tall.
Cells have skeletons
Like the bones inside our body, cells also have a kind of skeleton called the cytoskeleton (meaning “cellular skeleton”). It is made up of molecules called proteins. The skeleton of the cell makes it strong and also helps our cells to move through the body.
Cells have a brain (sort of)
One of the most important molecules in a cell is its DNA, which is made up of a type of building block called nucleotides. DNA is like an instruction manual for everything our cells need to do (including making more cells, moving around, and fighting germs). As the core stores most of our DNA, it’s like the brain of the cell.
You may have heard of genes (not the ones you carry, but the ones inside you). They are like a recipe that your cells use to make you! They decide your height, eye or hair color, etc.
Our genes are made of DNA and we get that DNA from our mother and our father. For example, if a dad has brown eyes, he can pass on his DNA recipe to his child who tells his cells how to make brown eyes. This explains why we can look like our parents.
Cells have stomachs
When you are hungry, you eat! Your stomach then breaks down your food, in a process called digestion. Just like that, your cells also have their own mini-stomachs which are important for digesting food and cell waste and keeping them happy.
cells produce energy
If you turn on a switch, the room lights up quickly. It is because of electricity which is a type of energy, made in large power plants. We use electricity for so many things like lights but also televisions, telephones, heating and air conditioning.
Almost everything that happens inside a cell also needs energy. Therefore, cells contain special sections called mitochondriawhich are the powerhouses of the cell and produce all the energy the cell needs to function.
Cells can talk to each other!
If our cells are so small and our body so big, how can all our cells work together? The answer is that they can talk…well, sort of.
Instead of picking up the phone to talk to each other, our cells need to send messages. These messages are made up of molecules that help cells communicate.
Here is a cool example. If you get stung by a bee (ouch!), your skin will start to redden and swell. It may sound scary, but it’s actually your body helping you. Cells in this area quickly send help messages. Cells in other areas receive these messages and then go to the rescue.
As scientists, we know a lot about cells. But we still don’t know everything. That’s why we need young children to stay curious and ask questions, like Béa!
Hello, curious little ones! Do you have a question you would like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au
