2.2

Question 1

Factors that affect rate of osmosis

Answer 1

• water potential gradient
• distance over which water molecules need to move (ie. thickness of membrane
• surface area-to-volume ratio

Question 2

Turgor pressure

Answer 2

Pressure exerted by the Water in the vacuole

Question 3

When plant cell placed in a lower water potential solution( 4pts )

Answer 3

1. Cell sap has higher water p than solution outside of cell
2. By osmosis, water from the vacuole and cytoplasm leaves the cell thru partially permeable membrane
3. Cell loses water, vacuole decrease in size
   Plamolysis = cell membrane and cytoplasm shrinks
   ( can be restored jf placed in sol of higher wp)
   - cell decreases in size and becomes flaccid

Question 4

dilute solution

Answer 4

small amt of solute dissolved in a solution

Question 5

concentrated solution

Answer 5

large amounts of solute dissolved in a solution

Question 6

what is osmosis?

Answer 6

osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential, down a water-potential gradient, through a partially permeable membrane.

Question 7

what is diffusion?

Answer 7

diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient.

no partially permeable membrane needed

Question 8

when a plant cell placed in a higher water potential solution

Answer 8

1. the water solution has higher water potential than the cell.
2. through osmosis, water molecules enter the cell through partially permeable membrane
3. causing the vacuole to increase in size and pushes the cytoplasm against the cell wall.
4. the cell **will not burst **bc protected by inelastic cell wall, but it will swell up and become turgid

Question 9

plas-moly-sis

Answer 9

= cell membrane and cytoplasm shrinks
( can be restored jf placed in sol of higher wp)

Question 10

animal cell placed in higher water potential of solution

Answer 10

it will burst

Question 11

animal cell placed in lower water potential of solution

Answer 11

1. solution has lower water potential than animal cell
2. by osmosis, the water molecules move out of the cell
3. cell shrinks and spikes appear on the **cell surface. ** = crenation
4. cell will be dehydrated and die.

Question 12

crenation

Answer 12

when a cell shrinks and spikes appear on the cell surface.

Question 13

cell in a sol of same water potential

Answer 13

no net movement of water molecules in and out of cell

Question 14

turgor

Answer 14

helps plants remain firm and erect