dissolved substances like sugars, sucrose and amino acids
1 of 12
what is translocation?
an energy requiring process involving the movement of dissolved substances from source to sink to where they're needed in a plant via the phloem
2 of 12
what are dissolved substances called?
assimilates
3 of 12
what is the source?
where a substance is made and it has a higher conc.
4 of 12
what is the sink?
the area where it is used up and is at a lower conc.
5 of 12
give an example of source and sink using sucrose
-source is at the leaves (made by photosynthesis) -sink is other parts of the plant e.g. food storage organs and meristems (areas of growth) in roots, stems and leaves
6 of 12
give an example of parts of the pant that can be both source and sink
-sucrose can be stroed in roots -sucose can be transported to the leaves from the roots to provide them with energy for growth -> roots are source and leaves the sink
7 of 12
how do enzymes maintain a conc. gradient from source to sink?
by changing the dissolved substances at the sink (e.g. breaking them down) -> ensures that there is always a lower conc. at the sink than source
8 of 12
give an example of this
-in potatoes, sucrose is converted to starch in sink areas, so there's always a lower conc. of sucrose at sink than in the phloem -> ensures that there is a constant supply of new sucrose reaching the sink -sucrose can be broken down into glucose
9 of 12
what are assimilates?
substances that becomes incorporated into the plant tissue
10 of 12
why are sugars transported as sucrose?
sucrose in soluble and metabolically inactive, so it doesn't get used up during transport
11 of 12
what does the mass flow hypothesis involve?
1. source 2. sink 3. flow
12 of 12
Other cards in this set
Card 2
Front
what is translocation?
Back
an energy requiring process involving the movement of dissolved substances from source to sink to where they're needed in a plant via the phloem
Comments
No comments have yet been made