Diffusion and Osmosis

Question 1

Are all biological membranes similar?

Answer 1

Yes

Question 2

What do selectively permeable membranes do?

Answer 2

Allow some substances to pass through easily, but other substances cannot pass through easily.

Question 3

What is diffusion?

Answer 3

Movement of molecules from a region of higher concentration to a region of lower concentration.

Question 4

What is active transport?

Answer 4

Movement of molecules from a less crowded area to a more crowded area with the use of energy.

Question 5

Name four membranes in plant and animal cells.

Answer 5

• Cell membranes
• Mitochondrial membranes
• Chloroplast membranes
• Nuclear membranes

Question 6

Do all membranes act in the same way?

Answer 6

Yes.

Question 7

What does permeable mean?

Answer 7

It means it lets everything in and out

Question 8

What does semi-permeable mean?

Answer 8

Lets some things in and out

Question 9

What does impermeable mean?

Answer 9

Lets nothing in and out

Question 10

Give an example of a material that has a selectively permeable membrane.

Answer 10

Visking tubing

Question 11

What does diffusion occur in?

Answer 11

-Liquids and gases

Question 12

Does diffusion need energy?

Answer 12

No, it is passive

Question 13

Give a few examples of diffusion in everyday life.

Answer 13

• Smell of perfume
• Bread baking
• Stink bomb
• Food colouring in water
• Sugar in tea

Question 14

What is a solvent?

Answer 14

Liquid that dissolves the solute

Question 15

What is the solute?

Answer 15

Substance that has been dissolved

Question 16

What is the solution?

Answer 16

Mixture of solute and solvent

Question 17

What is osmosis?

Answer 17

Is the movement of water across a semipermeable membrane from a region of high water concentration to a region of low water concentration.

Question 18

Is osmosis passive?

Answer 18

Yes

Question 19

What happens to an animal cell surrounded by a solution that is the same concentration as the cytoplasm in the cell?

Answer 19

Water will move in and out at the same rate and the cell will remain intact.

Question 20

Are plant cell walls fully permeable?

Answer 20

Yes

Question 21

What does turgor mean?

Answer 21

When water enter the plant cell, leading the swelling of the cytoplasm and vacoule, meaning the membranes push against the cell wall

Question 22

What does this turgor pressure do?

Answer 22

Give plants their strength, without it plants will wilt.

Question 23

What is plasmolysis?

Answer 23

When the cell wall stays intact but the membrane shrivel up away from it due to water loss (osmosis)

Question 24

Is osmosis used in food preservation?

Answer 24

Yes. If food is placed in a sugary or salty solution then any bacteria or fungi present will lose water in their cells to the more concentrated solution outside

Question 25

Name examples of osmosis and food preservation.

Answer 25

• Fish and meat may be stored in a salty solution

- Jams, marmalades and tinned foods are stored in a sugary solution

Question 26

How do amoeba survive in freshwater (less concentrated environment)

Answer 26

They have a contractile vacuole which eliminates water.