Specialised plant cells Questions

Question 1

Root hairs cells are on the outsides of roots. Describe how these cells are adapted to take up water and mineral ions.

Answer 1

Root hair cells have long extensions that stretch out into the soil. This gives them a large surface area where osmosis can take place, which means that more water molecules can cross the cell membrane into the cell at the same time.

This also gives a large surface area for mineral ions to enter the root hair cell by diffusion and active transport.

Question 2

Explain the meaning of the phrase active transport. Use minerals entering roots as your example.

Answer 2

Mineral salts cannot enter the root cells from soil water by diffusion because there is a higher concentration of mineral salts in the cells than in the soil. So the root cells have to use energy to transport mineral salts into the cell against their concentration gradient.

Question 3

Explain how the structure of root hair cells is adapted to support active transport of mineral ions into roots.

Answer 3

• contain many mitochondria

- supply energy from respiration for active transport of mineral ions

Question 4

Describe three adaptations of xylem vessels and explain how these adapt the cells for transporting water through the plant.

Answer 4

Pits/pores in side walls; for sideways movement of water/mineral ions

No cell contents; water flow not obstructed

No end walls; water flow not obstructed

Thick walls made of lignin; so cell does not collapse/ for strength