Bricks of life
Zoom in. Every living body is built from tiny units.
One solid thing?
In 1665, Robert Hooke looked at a thin slice of cork through his microscope. It did not look solid. It was full of tiny empty spaces, like a honeycomb. He called each space a cell.
A thin onion peel looks like one smooth skin. What do you think it is really made of?
What this lesson covers
The idea
All living beings are made up of cells; the cell is the basic unit of life, just as a brick is the basic unit of a wall.
One solid thing?
In 1665, Robert Hooke looked at a thin slice of cork through his microscope. It did not look solid. It was full of tiny empty spaces, like a honeycomb. He called each space a cell.
A thin onion peel looks like one smooth skin. What do you think it is really made of?
- One single solid piece
- Many tiny units packed together
- Only water
Zoom in
Use a microscope on each picture. First look at a wall, then at an onion peel.
Brick and cell
The cell is the basic unit of life, just as a brick is the basic unit of a wall. All living beings are made of cells.
All plants are made of cells. All animals are made of cells too.
- Looks like | Built from
- A wall | One solid thing | Many bricks
- An onion peel | One thin skin | Many cells
Notes
All living beings are made up of cells. The cell is the basic unit of life, just as a brick is the basic unit of a wall.
Check yourself
Hooke looked at a thin slice of cork. What did he call each small empty space he saw?
A wall is built from bricks. What is a living body built from?
Which statement is right?
- A brick. A brick is what a wall is built from. Hooke gave the tiny spaces a different name.
- A cell — correct. Yes. The spaces reminded him of a honeycomb, and he called each one a cell.
- A lens. A lens is the curved glass in a microscope, not a space in the cork.
- Cells — correct. Yes. The cell is the basic unit of life, as the brick is the basic unit of a wall.
- Bricks. Bricks build walls. Living things are built from a different tiny unit.
- Only big organs. Organs are made of cells too. The cell is the smaller, basic unit.
- Only animals are made of cells.. Plants are made of cells too. The onion peel showed that.
- All living beings, plants and animals, are made of cells. — correct. Yes. Every living being is made up of cells.
- Only things we can see are made of cells.. Cells are tiny. We need a microscope to see them.