Rocket dumps a bucket of tiny snap blocks on the lab floor. "I will build a whole body!" he says.
He snaps fast. The tower wobbles and tips over. Rocket laughs. "Too fast again!"
Raven picks up one block. "What do you notice about a big tower?" she asks.
Nova hovers close. "Look at the smallest piece," she says. "Bodies have tiny pieces too."
Your body is built from cells.
A cell is the smallest building block of every living thing.
You have trillions of cells. That is more than you could ever count!
Most cells are far too small to see without a microscope.
Cells do many jobs. Some cells help change food into energy.
Cells come in many types, sizes and shapes.
Still, most cells share three main parts.
The cell membrane is the outer edge. It controls what goes in and out.
The nucleus is the control center of the cell.
The cytoplasm fills the space between the membrane and the nucleus.
| Cell part | Its job | It is a bit like... |
|---|---|---|
| cell membrane | Controls what goes in and out | a gate around a park |
| nucleus | The control center | a captain giving orders |
| cytoplasm | Fills the inside of the cell | the space inside a room |
| Statement | True or false? |
|---|---|
| All cells are exactly the same shape. | ? |
| You can see most cells with just your eyes. | ? |
| The cell membrane controls what goes in and out. | ? |
| Some cells help change food into energy. | ? |
Great thinking, cell scientist! Tomorrow we find out what happens when cells team up.