Nutreints transport

Question 1

translocation

Answer 1

movement of sucrose throughout the phloem for growth, metabolism or storage

Question 2

pressure flow model

Answer 2

explains how sucrose is moved from a source (region where it enters sieve tube elements) to a sink (the region where it is being used or stored)
uses osmosis and pressure dynamics to show how sucrose moves through the phloem

Question 3

sucrose movement

Answer 3

1. Sucrose is moved via active transport (since it has to move against its concentration gradients), from the source (for example, leaves in summer) to its sink (roots for storage).
2. Sucrose diffuses into the companion cell, but an equilibrium is reached, so sucrose is pushed from source to phloem (sieve tube elements), where water enters via osmosis, forming sap (solution of water and sugar)
3. Water creates a buildup of pressure at the source, so sap moves to the sink where there is low pressure.