The rigid outer wall
Plant cells have a wall outside the membrane.
Standing in the wind
A tree cannot walk away from wind and rain. It has to stand firm, in one place, day after day.
What might help plant cells stay firm?
What this lesson covers
The idea
Cells of plants, fungi and bacteria have a rigid cell wall outside the cell membrane giving protection and structural support; the plant cell wall, made mainly of cellulose (many linked glucose units), keeps plants firm and upright.
Standing in the wind
A tree cannot walk away from wind and rain. It has to stand firm, in one place, day after day.
What might help plant cells stay firm?
- A rigid covering outside the cell membrane
- Nothing; plants just lean on the ground
- They are full of air
The squeeze test
Press both cells from the sides. Then remove the plant cell’s wall and press again.
The cell wall
Cells of plants, fungi and bacteria have a rigid cell wall outside the cell membrane. It gives protection and structural support. The plant cell wall is made mainly of cellulose, many glucose units linked together, and it keeps plants firm and upright.
Animal cells can change shape easily because they have no wall. This flexibility supports the movement of animal tissues.
- Cell | Cell wall?
- Plant | yes (cellulose)
- Fungi | yes
- Bacteria | yes
- Animal | no, so the shape can change easily
Notes
Plant, fungus and bacterial cells have a rigid cell wall outside the membrane for protection and support. The plant wall is made mainly of cellulose.
Check yourself
Which cells have a cell wall?
The plant cell wall is made mainly of…
Why can animal cells change shape easily?
How many of these have a cell wall: plant, fungus, bacterium, animal?
Answer: 3
Plant, fungus and bacterium have a cell wall: 3. Animal cells do not.
- Plants, fungi and bacteria — correct. Yes.
- Animal cells only. Animal cells do not have one.
- All cells. Animal cells lack a wall.
- cellulose — correct. Yes. A carbohydrate made of many glucose units linked together.
- protein only. The wall is mainly cellulose.
- water. Water fills cells but is not the wall.
- They have no rigid cell wall — correct. Yes.
- They have more water than plants. The reason is the missing wall.
- They have no membrane. Every cell has a membrane.