Osmosis

Question 1

What is osmosis ?? Definition.

Answer 1

The passage of water from a region of High water potential to an area of low water potential via a partially permeable membrane.

Question 2

How does a semi-permeable membrane work ?

Answer 2

It has tiny holes which allow small molecules like water through.

Question 3

What is a hypertonic solution ?

Answer 3

High concentration of solutes. Water potential is lower outside the cell.

Question 4

What is a hypotonic solution ?

Answer 4

Low concentration of solutes. Water potential is higher outside the cell.

Question 5

What is an isotonic solution ??

Answer 5

Water potential is equal inside and outside the cell.

Question 6

What is a solute.

Answer 6

A substance dissolved in a solvent and together they form a solvent.

Question 7

What is the water potential of pure water.

Answer 7

Zero

Question 8

What happens when you add a solute to water.

Answer 8

The water potential decreases to below zero the more solute added.

Question 9

What is water potential measured in ?

Answer 9

kPa (kiloPascals).

Question 10

What is the definition of water potential ?

Answer 10

It is a measure of the pressure exerted by the movement of water.
The more water can move, the greater it’s water potential.

Question 11

What happens to the water potential of a solution when a solute is added.

Answer 11

Water potential will decrease as the water molecules will cluster around the solute.

Question 12

What happens to a cell if placed in an isotonic solution ?

Answer 12

The same amount of water enters the cell as moves out so the cell is not damaged.

Question 13

What happens if the cell is placed in a hypotonic solution ?

Answer 13

Water will move in causing the cell to expand.

Question 14

What will happen if a cell is placed in a hypertonic solution ?

Answer 14

Water leaves the cell causing it to shrink.

Question 15

What happens if an animal cell is placed in a hypertonic solution ?

Answer 15

The cell shirinks. This is because there is a higher water potential in the cell so water leaves the cell from a high to low concentration by the process of osmosis via a partially permeable membrane.

Question 16

What happens if the cell is placed in a hypotonic solution ?

Answer 16

The cell expands as water has moved in. This means water potential is higher outside the cell therefore water has moved into the cell , down the concentration gradient by a process of osmosis via a partially permeable membrane.

Question 17

What happens when an animal cell is placed in an isotonic solution ?

Answer 17

The rate of water moving in an out of the cell is equal so the cell is unaffected. This is because the water potential is equal inside and outside the cell.

Question 18

What happens when plant cells are placed in a hypotonic solution.

Answer 18

They are turgid.
Water moves in causing the cell to expand and putting pressure on the cell wall.
The water potential outside the cell must be higher.

Question 19

What happens and what is it called when a plant cell is placed in an isotonic solution.

Answer 19

There is equal water potential inside and outside the cell which means that movement of water in and out the cell is at equal rate. There is therefore less pressure the cell surface membrane begins to pull away from the cell wall.
This is called incipient plasmolysis.

Question 20

What happens when a plant cell is placed in a hypertonic solution.

Answer 20

There is a lower water potential outside the cell therefore water moves out of the cell.
There is a lower turgid prayed so the cell surface membrane is broken away from the cell wall.

Question 21

What is it called when an animal cell is placed inside a hypotonic solution and water moves into the cell.

Answer 21

Lysed.

Question 22

What is it called when an animal cell is placed into a hypertonic solution and it begins to shrink.

Answer 22

Shrivelled.