3.3 Passage of water through plant

Question 1

what percentage of water passing through a plant is used for photosynthesis?

Answer 1

1%

Question 2

the 99% of water not used in photosynthesis evaporates from the leaves in which process?

Answer 2

transpiration

Question 3

what is the highest water potential?

Answer 3

0 (pure water)

Question 4

the more solute the ……. the water potential?

Answer 4

lower

Question 5

the greater the number of water particles the …….. the water potential?

Answer 5

higher

Question 6

what is water key in?

Answer 6

structure and metabolism of plants

Question 7

turgor/hydrostatic pressure is a result of what?

Answer 7

osmosis

Question 8

what does turgor/hydrostatic pressure create in plants?

Answer 8

hydrostatic skeleton

Question 9

what does turgor drive in plants?

Answer 9

cell expansion

Question 10

what does evaporation do to plants?

Answer 10

cools them down

Question 11

mineral ions and products of photosynthesis are transported in what?

Answer 11

aqueous solutions

Question 12

water is a raw material for what?

Answer 12

photosynthesis

Question 13

does soil solution have a high or low water potential? why?

Answer 13

high it is mainly eater with small quantities of mineral ions

Question 14

inside the root is there a high or low water potential?

Answer 14

low

Question 15

why is there a low water potential in the root?

Answer 15

there are amino acids, mineral ions and sugars

Question 16

water moves into the root hair cell down a what?

Answer 16

water potential gradient

Question 17

how are root hairs an adaptation to help absorb water?

Answer 17

increase root surface area which increases speed of water uptake

Question 18

how else are plant roots adapted to absorb water?

Answer 18

thin surface layer of cellulose wall and cell surface membrane (short diffusion distance)

Question 19

what are the two routes which the water can move from the root hair cell into the xylem?

Answer 19

apoplastic pathway

symplastic pathway

Question 20

what does the apoplastic pathway use?

Answer 20

the apoplast/outside

Question 21

what does the symplastic pathway use?

Answer 21

the symplast/middle

Question 22

water moves through the symplast by what process?

Answer 22

osmosis

Question 23

(symplast) due to water diffusing in from soil the root hair cell has higher water potential than the next cell, so what does water do?

Answer 23

moves from root hair to next cell along by osmosis

Question 24

(symplast) water moves from cell to cell until what is reached?

Answer 24

the xylem

Question 25

(symplast) when the xylem is reached water moves through which p?

Answer 25

plasmodesma

Question 26

what is the plasmodesma?

Answer 26

gaps between the cell

Question 27

(symplast) as water leaves the root hair what happens to the water potential of the cytoplasm? what does this maintain?

Answer 27

it decreases

maintaining steep water potential gradient

Question 28

in the apoplast pathway what does water fill?

Answer 28

spaces between network of fibres in cellulose cell wall

Question 29

(apoplast) as water moves into the xylem, what happens to more water molecules?

Answer 29

pulled through apoplast due to cohesive forces between molecules

Question 30

(apoplast) what do the cohesive forces between water molecules create?

Answer 30

tension

Question 31

(apoplast) what does the tension of the water result in?

Answer 31

continuous flow of water through the cellulose wall with little or no resistance

Question 32

in the apoplast pathway the water reaches the endodermis and the casparian strip, what is this?

Answer 32

waterproof band in the endodermal cells preventing the water from passing

Question 33

what happens to the water reaching the casparian strip by the apoplast?

Answer 33

forced into protoplast (living part) joining water from symplast

Question 34

what is the mechanism by which the water gets into the xylem from the symplast and apoplast?

Answer 34

active transport of salts into the xylem

Question 35

when endodermal cells actively transport salts into the xylem what does it create and what does it result in?

Answer 35

lower water potential so water moves into xylem by osmosis

creating force moving water up the plant - root pressure

Question 36

what happens to root pressure when temperature increases?

Answer 36

pressure increases

Question 37

temperature increase will increase the rate of production of what?

Answer 37

ATP

Question 38

why does increased temperature increase ATP production?

Answer 38

root pressure requires energy

ATP is produced by enzymes which work faster and more efficiently at high temperatures

Question 39

how do metabolic inhibitors affect root pressure?

Answer 39

prevent energy release by respiration, no energy for root pressure

Question 40

give an example of a metabolic inhibitor:

Answer 40

cyanide