Transport in Plants

Question 1

Xylem

Answer 1

Transports water and mineral ions in one direction from the roots to the leaves

Question 2

Phloem

Answer 2

Transports sucrose and amino acids between the leaves and the other parts of the plant, travelling up or down the plant

Question 3

How do root hair cells absorb water?

Answer 3

Osmosis

Question 4

Transpiration

Answer 4

Loss of water vapour from the leaves of a plant

Question 5

Factors affecting the rate of transpiration

Answer 5

• Light intensity - Increases due to the opening of the stomata so that photosynthesis can occur
• Temperature - Increased rate of evaporation and therefore transpiration
• Humidity - Decreases due to a reduced concentration gradient
• Wind speed - Increase since any water vapour is quickly moved away from the stomata, increasing the concentration gradient

Question 6

What is used to measure the rate of transpiration?

Answer 6

Potometer

Question 7

Why do simple unicellular organisms not need transport systems?

Answer 7

They can rely on diffusion for movement of substances in and out

Question 8

Why do large organisms need a transport system?

Answer 8

They cannot get all the oxygen they need through the surface - there isn’t enough surface to supply volume. To overcome this problem, large organism have evolved special gas exchange organs and circulatory systems, The same idea applies to obtaining nutrients