UNIT 2 : (2.5)

Question 1

what are the organs in a plant?

Answer 1

• roots
• stems
• leaves

Question 2

why do plants need water?

Answer 2

• carry out photosynthesis

- transported materials such as minerals or soluble food

Question 3

how are materials transported in plants?

Answer 3

water and minerals are transported up through the stem of a plant from roots to the leaves in dead xylem vessels

Question 4

what is the function of xylem vessels?

Answer 4

• transport water
• carry dissolved minerals
• support the plant

Question 5

what is the structure of xylem vessels?

Answer 5

• they are dead
• end walls are disintegrated to leave hollow tubes
• sidewalls are strengthened with rings or spirals of lignin

Question 6

what is transpiration?

Answer 6

the process of water moving through a plant and evaporating through the stomata of the leaf

Question 7

what is the first stage in transpiration?

Answer 7

water enters root hair cells by osmosis

Question 8

what is the second stage in transpiration?

Answer 8

the water in the vacuole of a root hair cell has a lower water concentration to the surrounding soil water.

Question 9

what is the third stage in transpiration?

Answer 9

water then moves from cell to cell through the root cortex by osmosis down a concentration gradient

Question 10

what is the fourth stage in transpiration?

Answer 10

in the centre of the root the water enters the xylem vessels

Question 11

what is the fifth stage in transpiration?

Answer 11

xylem vessels then carry water up the stem to the leaves of the plant where some of the water is lost to the atmosphere through stomata on the lower surface of a leaf

Question 12

what is used to measure the rate of uptake of water by a leafy shoot?

Answer 12

bubble potometer

Question 13

what is a phloem?

Answer 13

living vessels which carry sugars up and down the plant

Question 14

what do phloem cells have?

Answer 14

• sieve plates

- associated companion cells