7 EXCHANGE - plants

Question 1

What are the adaptations of xerophytes?

Answer 1

Thick waxy cuticle - reduces evaporation
Sunken Stomata - traps moist air near stomata, reduces transpiration
Hairs on leaves - reduces transpiration, traps moisture near stomata
Reduced number of stomata - reduces transpiration

Question 2

Phloem Structure

Answer 2

Companion cells for sieve tube element - carries out cell processes for sieve tube element
Sieve plates - allows substances to pass through quickly instead of diffusion
Sieve tube - where the translocation occurs, has bidirectional flow and perforated end walls

Question 3

What are sources and sinks?

Answer 3

Sources - where solutes are produced, therefore the solutes are in high concentration
Sinks - where solutes are used up, therefore the solutes are in low concentration