B2.2. Movement in and out of cells

Question 1

Define diffusion

Answer 1

The net movement of particles from a region of higher concentration to a region of lower concentration

Question 2

Is the cell membrane permeable?

Answer 2

Partially permeable

Question 3

Define osmosis

Answer 3

The net movement of water molecules from a region of high water potential to a region of low water potential, down the water potential gradient

Question 4

Define flaccid

Answer 4

• Occurs when water moves out of the cell via osmosis. The cell shrinks but the cell membrane does not peel away from the cell wall. If more water leaves the cell, it becomes plasmolyzed

Question 5

How do plant cells not burst?

Answer 5

• The cell wall maintains its shape

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Question 6

List the factors affecting the rate of diffusion

Answer 6

• Surface area
• Temperature
• Distance of diffusion
• Concentration gradient

Question 7

Define turgid

Answer 7

When cells become swollen due to a high-water content

Question 8

Define turgor pressure

Answer 8

The pressure of the water in the cytoplasm in a turgid cell against the cell wall

Question 9

Define plasmolysed

Answer 9

When a plant cell is dehydrated

Question 10

What is a stomata?

Answer 10

Holes that are in the surface of a leaf that allow air to move into and out of the leaf.

Question 11

Define water potential

Answer 11

The ability of a cell to draw water into itself

Question 12

Describe the effect of osmosis on animal cells

Answer 12

• water gain/loss more dramatic than plant cells

- the cell membrane is not strong so it will burst if stretched too far

Question 13

what will happen if a cell is placed in a concentrated solution (solution of high solute concentration)

Answer 13

water will leave the cell through osmosis as the water concentration inside the cell is higher than the water concentration outside.
Cytoplasm will shrink and it will become flaccid (wilting)

Question 14

what will happen if a cell is placed in a dilute solution (solution of pure water, low solute concentration)

Answer 14

water will enter the cell by osmosis. The cytoplasm and vacuole will swell but the cell won’t burst as the cell wall provides strength. (turgor pressure)

Question 15

what happens if you put an animal cell into a solution of low water potential

Answer 15

it will become crenated (shrink)

Question 16

what happens if you put an animal cell into a solution of high water potential

Answer 16

it will burst