3.2.3.3 - Osmosis Flashcards Preview

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Flashcards in 3.2.3.3 - Osmosis Deck (17):
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

give 2 similarities in the movement of substances by diffusion and osmosis

1. down a gradient (High to Low)
2. passive not active (does not use energy)