TOPIC 2- Osmosis

Question 1

What is osmosis?

Answer 1

The diffussion of water molecules across a partially permebale membrane from an area of high water potential to an area of low water potential

Question 2

Define water potential

Answer 2

The potential (likelihood) of water molecules to diffuse in and out of or into a solution

Question 3

Why can water molecules diffuse easily through the cell membranes and large solutes cannot?

Answer 3

They are small

Question 4

What is the water potential of pure water?

Answer 4

Zero

Question 5

What lowers the water potential of pure water?

Answer 5

Adding solutes

Question 6

What is the water potential of any solution?

Answer 6

Negative

Question 7

The more 1._____ the water potential the stronger the 2._____ of 3.____ in a solution

Answer 7

1. Negative
2. Concentration
3. Solutes

Question 8

Define isotonic

Answer 8

When two solutions have the same water potential

Question 9

What happens to cells in isotonic solutions?

Answer 9

-They will not gain or loose any water
-No net movement of water molecules
-Because there is no difference between the cell and the surrounding solution

Question 10

What will happen to a cell that is placed in a solution that has a higher water potential?

Answer 10

It will swell as water moves into it via osmosis

Question 11

Define hypotonic

Answer 11

Solutions with a higher water potential compared to the inside of the cell

Question 12

What will happen to a cell if it is placed in a solution which has a lower water potential?

Answer 12

May shrink as water moves out of it by osmosis

Question 13

Define hypertonic

Answer 13

Solutions with a lower water potential than the cell

Question 14

What are the factors affecting the rate of osmosis?

Answer 14

-Water potential gradient
-Thickness of the exchange surface
-The SA of the exchange surface

Question 15

What is a water potential gradient?

Answer 15

The difference in water potential between two regions

Question 16

How does the water potential gradient affect the rate of osmosis?

Answer 16

-The higher the water potential gradient, the faster the rate of osmosis
-As Osmosis takes place the difference in the water potential on either side of the membrane decreases
-The rate of osmosis levels off over time

Question 17

How does the thickness of the exchange surface affect the rate of osmosis?

Answer 17

The thinner the exchange surface, the faster rate of osmosis

Question 18

How does the surface area of the exchange surface affect the rate of osmosis

Answer 18

The larger the surface area the faster the rate of osmosis