Mass Transport

Question 1

Role of phloem

Answer 1

Transports organic substances from sources to sinks in plants
Known as translocation

Question 2

Phloem structure

Answer 2

Phloem tissue contains phloem sieve cells and companion cells which are closely associated with one another

Question 3

Companion cells

Answer 3

Have all the normal organelles including many mitochondria

Connected directly to phloem sieve elements via plasmodesmata

Question 4

Main things transported through phloem

Answer 4

Sucrose and amino acids

Question 5

Translocation process

Answer 5

Sucrose actively transported into phloem by source cells as well as water via osmosis also moving into phloem.
This increases hydrostatic pressure
Sucrose transported out of phloem into sink cells with water decreasing hydrostatic pressure
Sap in phloem therefore flows from high hydrostatic pressure to low hydrostatic pressure.

Question 6

Evidence for phloem

Answer 6

Ringing experiment in things such as trees

Radioactive tracers such as carbon tracers