Transport in Plants

Question 1

What does a phloem do?

Answer 1

It transports sugars, like sucrose, and amino acids between the leaves and other parts of the plant

Question 2

What are xylem made from?

Answer 2

Dead hollow cells

Question 3

What are phloem made from?

Answer 3

Living cells which have permeable cell walls

Question 4

What is transpiration?

Answer 4

The evaporation of water from the surface of a plant

Question 5

How do root hair cells take in water?

Answer 5

By osmosis

Question 6

Which four factors affect the rate of transpiration?

Answer 6

Temperature
Wind speed
Humidity
Light intensity

Question 7

How does humidity affect the rate of transpiration?

Answer 7

The drier the air around a leaf, the faster the rate of transpiration. Diffusion happens fastest when there’s a large difference in concentration.
If the air is humid it already contain lots of water.

Question 8

How does wind speed affect transpiration?

Answer 8

The higher the wind speed, the greater the transpiration rate.
If it’s windy, water molecules are moved away from the leaf and more evaporation can take place.

Question 9

How does temperature affect the rate of transpiration?

Answer 9

The higher the temperature, the faster the rate of transpiration.
When it’s warm, water particles have more energy to evaporate and diffuse out of the stomata.

Question 10

How does light intensity affect the rate of transpiration?

Answer 10

The brighter the light, the greater the transpiration rate.
Stomata close as it gets darker.
When the stomata are closed, very little water can escape.

Question 11

Describe an experiment using a bubble potometer

Answer 11

• cut a leafy shoot from a plant and fit it tightly into the bubble potometer underwater
• seal off all connections with Vaseline to ensure no leakage of water
• lift the end of the capillary tube from the beaker of water for 30 seconds and replace it to introduce an air bubble into the tube
• record the distance travelled by the bubble in a certain period of time (eg 5 minutes)
• repeat with changing variables specific to the aim of the experiment

Question 12

Describe an experiment using a mass potometer

Answer 12

• cut a leafy shoot and place it in a test tube filled with water
• pour a layer of oil to cover the full surface of the water
• measure the starting mass
• measure the change in mass throughout a set time period
• repeat with changing variables specific to the aim of he experiment

Question 13

What does a xylem do?

Answer 13

It transports water and mineral ions from the roots up the shoot to the leaves in the transpiration stream