Flashcards in Cells - Transport across cell membrane - 3.2.3.3 - Osmosis Deck (17)
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1
The passive movement of water from an area of high water potential to an area of low water potential through a selectively permeable membrane is...
OSMOSIS
2
Osmosis involves the movement of
water ONLY
3
By adding more solute the a solution how does this affect the water potential
it lowers the WP - becomes more negative
4
Why does pure water have a higher water potential than a solution of sugar
there are more 'free' water particles in pure water
5
A potato has a WP of -200kPa was placed in pure water WP 0kPa, what happens?
Water ENTERS the potato by osmosis (water moved from a high WP to a lower WP)
6
water potential is represented by
psi (greek letter)
7
water potential is measured in units of pressure which are
kPa
8
Pure water has a WP of
0kPa
9
How can you determine the the WP of a potato
place potato in a series of solutions of different WP. Where there is no net gain of water by the potato is the WP of the potato.
10
What happens if a red blood cell is placed in pure water
it swells and bursts - water enters the cell
11
What happens if a red blood cell is placed in strong sugar solution
It shrinks - water leaves the cell
12
What happens if a plant cell is placed in pure water
It swells - water enters the cell - it becomes turgid
13
What happens if a plant cell is placed in strong salt solution
water leaves the cell - it shrinks - it plasmolysed
14
What is meant by selectively permeable
Membrane only allows certain molecules through; it is only permeable to water and other small molecules `
15
During an osmosis practical, how and why do you dry the potato chips?
with a paper towel. To remove surface water - This would add to the mass - which we do not want
16
You must control the temperature during your osmosis practical - HOW?
Using a water bath and check the temperature at regular intervals using a thermometer
17
