Three basic parts

The idea

A cell has three basic parts: the outer cell membrane, the nucleus in the middle (covered by a thin membrane), and the cytoplasm filling the space between them; some cells also have an outer cell wall.

Inside a cell

Under a microscope, an onion peel cell is nearly rectangular, and the cells sit closely packed with no space between them. What is inside one cell?

How many main parts do you think a cell has?

• 1, it is just a bag
• 3 basic parts
• 10 or more

Find each part

This is an onion peel cell. Read each clue, then tap the matching part. A right tap shows its name.

Three basic parts

A cell has three basic parts: the cell membrane (outer layer), the nucleus (round, in the middle, covered by a thin membrane) and the cytoplasm (fills the space between them).

Some cells, like onion peel cells, also have an extra outer layer called the cell wall.

Notes

A cell has three basic parts: the cell membrane, the nucleus (covered by a thin membrane) and the cytoplasm between them. Some cells also have an outer cell wall.

Check yourself

Which part fills the space between the cell membrane and the nucleus?

Which of these is not one of the three basic parts of a cell?

How many basic parts does a cell have? (Count the membrane, the cytoplasm and the nucleus.)

Answer: 3

Three: the cell membrane, the cytoplasm and the nucleus. Some cells also have a cell wall.

• Cell wall. The cell wall is outside the cell membrane, not between the membrane and the nucleus.
• Cytoplasm — correct. Yes. The cytoplasm fills the space between the cell membrane and the nucleus.
• Nucleus. The nucleus is the round structure in the middle. It is not the filling.
• Cell membrane. It is a basic part: the outer layer of every cell.
• Cell wall — correct. Yes. The cell wall is an extra layer found only in some cells. The three basic parts are the membrane, cytoplasm and nucleus.
• Nucleus. It is a basic part: the round structure in the middle.