AS bio revision help ASAPWatch
if any1 is doing unit 1 ocr as biology, can u please give me any info that u know?
With the Phloem:
1) Protons are actively loaded out of the companion cells using ATP
2) This creates a electrochemical or proton gradient, as there are more protons outside the cell than inside
3) This allows for facilitated diffusion of protons with sucrose molecules back into the cell through special transporter proteins. Thus Sucrose moves into the cells.
4) Sucrose then move into the sieve tube elements through the plasmodesmata
Hope this helps.