Osmosis And Plant Transport

Question 1

What is osmosis? (4)

Answer 1

• A form of diffusion
• involving the movement of water molecules
• through a selectively permeable membrane
• From a dilute solution to a concentrated solution

Question 2

What is meant when describing a cell as turgid? (2)

Answer 2

• When the vacuole inside of a plant cell increases in size,
• this increases pressure in the cell due to the vacuole pushing against the cell wall

Question 3

What form of pressure is seen when a plant cell is turgid (firm)

Answer 3

Turgor pressure

Question 4

What occurs in an animal cell when water enters it? (4)

Answer 4

• Cell increases in volume
• cell membrane stretches
• if continued, cell membrane splits
• cell bursts (lysis)

Question 5

What is plasmolysis (3)

Answer 5

• When cells lose water and
• the cell membrane pulls away from the cell wall
• due to the cells content shrinking

Question 6

What three ways do substances move in and out of cells?

Answer 6

• diffusion
• active transport
• osmosis

Question 7

What is transpiration? (2)

Answer 7

• The loss of water from a plant cell via evaporation
• This causes water to diffuse out of the stomata

Question 8

Where does transpiration occur?

Answer 8

Spongy mesophyll cells

Question 9

What are the 4 functions of water in plants?

Answer 9

• water for transpiration
• photosynthesis
• transport of minerals (roots to stem to leaves and other parts of the plant)
• cell support through turgor

Question 10

What conditions affect rate of transpiration? (3)

Answer 10

• Humidity
• temperature
• wind conditions

Question 11

What is the role of the cell wall of a plant? (2)

Answer 11

• To restrict water intake to prevent cell bursting
• to provide structural support

Question 12

How does osmosis move

Answer 12

Down the diffusion gradient

(High to low)

Question 13

How does osmosis affect if a cell is:

turgid
or
plasmolysed?

Answer 13

Cells become turgid due to
- Higher concentration of water outside cell
- to lower concentration of water in cell sap
(From outside cell to inside cell)

Cells become plasmolysed due to
- Higher concentration of water inside cell sap
- to lower concentration of water outside cell

(From cell to outside cell)

Question 14

What is active transport/uptake?

Give an example. (4)

Answer 14

• The absorption of a molecule
• against the concentration gradient
• requiring energy
• e.g. roots of plants absorbing minerals like magnesium