B9a Transpiration

Question 1

Name the organ shown in the diagram

Answer 1

Leaf

Question 2

Name the tissue labelled C

Answer 2

Spongy mesophyll

Question 3

Name the tissue labelled B

Answer 3

Palisade mesophyll

Question 4

Name the tissue labelled A

Answer 4

Upper epidermis

Question 5

The tubes that transport water and mineral ions are called …

Answer 5

Xylem

Question 6

How is the xylem adapted for its function?

Answer 6

Dead cells
Form continuous hollow tube from root to shoot
Strengthened and waterproofed with lignin

Question 7

Which plant organ is used to absorb water and mineral ions?

Answer 7

Root

Question 8

Name the process used to absorb water from the soil.

Answer 8

Osmosis

Question 9

Name the process used to absorb mineral ions from the soil

Answer 9

Active transport

Question 10

Name the specialised cells used to increase the surface area

of the root in contact with the soil.

Answer 10

Root hair cells

Question 11

How are the root hair cells adapted for their function?

Answer 11

Large surface area
Lots of mitochondria to release energy for active transport

Question 12

What is transpiration?

Answer 12

Transpiration is the evaporation of water vapour and its diffusion through the stomata

Question 13

How does transpiration move water up a plant?

Answer 13

Water evaporates from the mesophyll cells and diffuses out of the stomata
Water is pulled out of the xylem vessel to replace the lost water.
Water molecules in the xylem stick to each other and are pulled up the xylem.
Water is absorbed by the roots and travels to the xylem vessel.

Question 14

Explain how an increase in temperature affects the rate of transpiration

Answer 14

Increasing temperature increases the rate of transpiration.

More water converted into water vapour (evaporation)
Faster diffusion through stomata as molecules moving faster.

Question 15

Explain how humidity affects the rate of transpiration

Answer 15

Increasing humidity decreases the rate of transpiration.

High concentration of water vapour in the atmosphere around the leaf reduces the concentration gradient and causes less water to leave the leaf.

Question 16

Explain how wind speed affects the rate of transpiration

Answer 16

Increasing wind speed/ air movement increases the rate of transpiration

Increase air movement reduces the water vapour concentration outside the leaf. The concentration gradient is reduced and less water diffuses out of the leaf.

Question 17

Explain how light intensity affects the rate of transpiration

Answer 17

Increasing light intensity increases the rate of transpiration

More stomata open to allow carbon dioxide into the leaf for photosynthesis.
More water vapour can escape from the leaf.

Question 18

Name the organs of a plant involved in the transport of
substances around the plant

Answer 18

Root, stem and leaves

Question 19

Name the cells that surround the stomata and what is their function?

Answer 19

Guard cells

Open the stomata during the day to allow gas exchange for photosynthesis.
Close the stomata at night to reduce water loss. and close the stomata

Question 20

In which direction does water travel in a plant?

Answer 20

From root to shoot

Question 21

Name the cells shown on the picture

Answer 21

Guard cells