7. Transport In Plants

Question 2

water role

Answer 2

some mineral ions and organic compounds can be transported within plants dissolved in water

Question 3

describe the transport of water from the soil to the xylem

Answer 3

• apoplast pathway, including reference to lignin and cellulose.
• symplast pathway, including reference to the endodermis, Casparian strip and suberin.

Question 4

transpiration process

Answer 4

transpiration involves the evaporation of water
from the internal surfaces of leaves followed by diffusion of
water vapour to the atmosphere

Question 5

movement of water in the xylem

Answer 5

hydrogen bonding of water molecules is involved with movement of water in the xylem by cohesion-tension in
transpiration pull and by adhesion to cellulose in cell walls

Question 6

xerophytic plants

Answer 6

adapted to reduce water loss by transpiration. reduce diffusion of water VAPOUR out via the stomata

thick waxy cuticle- increase waterproof layer for increased diffusion distance.

sunken stoma- decrease water potential as humid air collects near external environment.

Question 7

translocation

Answer 7

assimilates dissolved in water, such as sucrose and amino acids, move from sources to sinks in phloem sieve
tubes

Question 8

companion cells transfer assimilates to phloem sieve tubes

Answer 8

companion cells transfer assimilates to phloem sieve tubes, with reference to proton pumps and cotransporter proteins

Question 9

explain mass flow in phloem sieve tubes

Answer 9

explain mass flow in phloem sieve tubes down a hydrostatic pressure gradient from source to sink