Lecture 3 - Osmosis and Hydrostatic pressure

Question 1

Important mechanisms for water movement in plants

Answer 1

Osmosis
Turgor pressure
Plasmolysis

Question 2

the solute potential is _____ when solutes are added to an aqueous system

Answer 2

reduced

Question 3

osmosis

Answer 3

phenomenon of water flow across a semi-permeable membrane

Question 4

how does concentration even out if sucrose cannot pass through the membrane

Answer 4

water can pass through, so it evens out through osmosis

Question 5

what do plants use to regulate pressure potential

Answer 5

solutes

Question 6

what is the typical pressure inside a cell

Answer 6

0.5-1.5 MPa

Question 7

how does a plant cell prevent bursting or deformity

Answer 7

rigidity of plant cell wall prevent the osmotic lysis by hydrostatic pressure

Question 8

plasmolyzed

Answer 8

vacuole shrinks because water moves out

Question 9

hypertonic

Answer 9

water moving out of the cell

Question 10

isotonic

Answer 10

water moves in and out of the cell equally (no pressure)

Question 11

flaccid

Answer 11

no pressure in the vacuole

Question 12

hypotonic

Answer 12

water moves into the cell

Question 13

turgid

Answer 13

vacuole expands from water moving in

Question 14

turgor pressure

Answer 14

pressure from fluid within the cell pushing agianst the cell wall

Question 15

what are aquaporins used for

Answer 15

used for water transport through the plasma membrane and water movement in cells

Question 16

expression of aquaporins _______ water uptake

Answer 16

accelerates

Question 17

how does water move through the aquaporin

Answer 17

water diffuses through pore
water is pulled through channel by cohesion
pressure increase to match solute potential until equilibrium is reached
no more water moves in

Question 18

tetrameric arrangement

Answer 18

each monomer forms a water channel

Question 19

how do aquaporins open and close

Answer 19

through phosphorylation and pH

Question 20

how does a aquaporin close in drought conditions

Answer 20

it is dephosphorylated

Question 21

how does a aquaporin close in flood conditions

Answer 21

drops the pH value by attracting more H+ ions

Question 22

in what state does a aquaporin remain open

Answer 22

when it is phosphorylated