Translocation

Question 1

What is translocation

Answer 1

The process by which organic molecules and some mineral ions are transported from one part of a plant to another

Question 2

Describe the structure of the phloem

Answer 2

-made up of sieve tube elements which are log thin structures arranged end to end
-Their end walls are perforated to form sieve plates
-associated with the sieve tub elements are cells called companion cells

Question 3

The process of the transfer of sucrose into sieve elements from photosynthesising tissue

Answer 3

Sucrose is manufactured from the products of photosynthesis in the cells. The sucrose diffuses down a concentration gradient by facilitated diffusion from the photosynthesising cells into companion cells. Hydrogen ions are actively transported from companion cells into the spaces within cell walls using ATP. These hydrogen ions, then the defuse down a concentration gradient through carrier proteins into the sieve tube elements. Sucrose molecules are transported along with the hydrogen ions in a process known as co-transport. The protein carriers are therefore also known as co-transport proteins.