Osmosis

Question 1

Define Osmosis

Answer 1

The movement of water through a selectively/partially permeable membrane from a region of higher water potential to a region of lower water potential

Question 2

What is water potential measured in

Answer 2

Kilopascals (kPa)

Question 3

What is the water potential of pure water

Answer 3

0 kPa

Question 4

Why are cell’s cytoplasm’s water potential negative

Answer 4

The cytoplasm contains dissolved sugars, salts etc, so water potential is more negative.

Question 5

what are the water molecules of solutions with a high water potential able to do

Answer 5

A large number of water molecules are free to move

Question 6

What is a solution with less solute and more water called

Answer 6

Hypotonic

Question 7

What is a solution with less water and more solute called

Answer 7

Hypertonic

Question 8

Which has a higher water potential - a diluted solution or a concentrated solution

Answer 8

Dilute

Question 9

What is a solution with the same amount of solute and water called

Answer 9

Isotonic

Question 10

What symbol is given to represent water potential

Answer 10

Psi - Ψ

Question 11

Define water potential

Answer 11

The pressure exerted by water molecules in a solution

Question 12

What do all solutions have in common in terms of water potential

Answer 12

They all have a water potential less than 0

Question 13

What happens to animal cells when pure water moves in by osmosis

Answer 13

Animal cell becomes haemolysed (Bursts)

Question 14

What happens to plant cells when pure water moves in by osmosis

Answer 14

Doesn’t burst as it has a cell wall, cell membrane pushes against cell wall, cell is turgid.

Question 15

What happens to plant/animal cells when in concentrated sugar solution

Answer 15

Water moves out of cells by osmosis down a water potential gradient.

Question 16

what happens to animal cells as water leaves them when the cell’s in a concentrated solution

Answer 16

They shrink and appear wrinkled, it is crenated.

Question 17

what happens to plant cells as water leaves them when the cell’s in a concentrated solution

Answer 17

Plant cell membrane pulls away from the cell wall as water leaves the cell is plasmolysed

Question 18

How does the body prevent its cells becoming crenated

Answer 18

Osmoregulation involving the kidneys ensures the concentration of the blood remains about the same as the concentration of the cell contents.