Water Transport in Plant Cells Flashcards
1
Q
3 transport scales
A
- local transport of water and solutes by individual cells (single-cell root hairs) by diffusion
- short-distance transport of substances from cell to cell at levels of tissues/organs (roots)
- long-distance transport within xylem at level of the whole plant
2
Q
Movement of water and solutes depend on what?
A
selective permeability of membranes
3
Q
what is selective permeability of membranes?
A
- control movement of solutes (nutrients, photosynthate) into and out of cells
- plant cell maintain internal environment
4
Q
what are the movement of water and solutes transport proteins?
A
- passive transport
- active transport
5
Q
What is passive transport ?
A
- facilitated diffusion
- osmosis
6
Q
Example of facilitated diffusion
A
channels/carriers
7
Q
Example of osmosis
A
aquaporins
8
Q
What is active transport?
A
-proton pumps
- secondary active transport
9
Q
What pumps do plants have?
A
proton pumps
10
Q
What does electrochemical gradient - proton motive force (pmf) do?
A
- concentration gradient
- charge gradient (membrane potential)
11
Q
What does proton pump do?
A
- pump actively move protons across membrane with ATP
- build a potential energy on one side of membrane
12
Q
What is potential energy used for?
A
- work of moving other substances across membrane
13
Q
What is the use of proton pumps?
A
- cation uptake (K+, NH3+) using membrane potential (delta charge)
- anion (Cl-, NO3-) uptake to facilitated proton diffusion using cotransport (symport protein)
- neutral solute (sugar) uptake to facilitated proton diffusion using cotransport (symport protein)
14
Q
How does water move?
A
passively thru osmosis
15
Q
What does water energy have?
A
free energy - chemical potential
