Diffusion And Osmosis

Question 1

Describe diffusion

Answer 1

The movement of a substance from a region of high to low concentration

Question 2

How does water move in and out of plant cells?

Answer 2

By osmosis through the cell membrane

Question 3

What is the purpose of a plant cell wall?

Answer 3

To provide support

Question 4

What can a lack of water cause plants to do?

Answer 4

Wilt

Question 5

Where does water move in and out of animal cells?

Answer 5

Through the cell membrane

Question 6

Describe how carbon dioxide and oxygen diffuse in and out if plants through the leaves

Answer 6

• The concentration of carbon dioxide outside the cell is greater than the concentration inside, so carbon dioxide diffuses into the cell
• The concentration of oxygen inside the cell is greater than the concentration inside, so oxygen diffuses out of the cell

Question 7

Explain the net movement of particles by diffusion

Answer 7

From an area of high concentration to an area of low concentration, as a consequence of the random movement of individual particles.

Question 8

Explain how the rate of diffusion is increased

Answer 8

• the particles have a shorter distance to travel
• the cell membrane’s surface area is bigger
• there is a bigger difference between concentrations (a steeper concentration gradient)

Question 9

How do substances move in and out cells by diffusion through the cell membrane?

Answer 9

By diffusion through the cell membrane

Question 10

Describe osmosis

Answer 10

The movement of water across a partially-permeable membrane from an area of high water concentration to an area of low water concentration

Question 11

What is osmosis?

Answer 11

A type of diffusion

Question 12

Explain the term partially-permeable membrane

Answer 12

Membrane that allows only certain molecules or atoms through, graded by size

Question 13

Explain how plants are supported by turgor pressure within cells

Answer 13

Water pressure activity ng against inelastic cell wall

Question 14

Explain wilting in terms of a lack of turgor pressure

Answer 14

As the amount of water inside the cells reduces, the cells become less rigid due to reduced pressure

Question 15

Describe the effects of the uptake and loss of water on animal cells

Answer 15

If too much water enters a cell it could burst

If too little water they shrivel up and become crenated

Question 16

Explain the net movement of water molecules by osmosis

Answer 16

From an area of high water concentration to an area of low water concentration across a partially permeable membrane, as a consequence of the random movement of individual particles.

Question 17

Explain the term flaccid

Answer 17

A plant cell that is limp through a reduction or pressure inside the cell

Question 18

Explain the term plasmolysed

Answer 18

A plant cell that has lost water causing the cell membrane to be pulled away from the inside of the cell wall

Question 19

Explain the term turgid

Answer 19

A plant cell fully inflated with water