TRANSPORT IN PLANTS END OF UNIT TEST

What is a function of phloem but not xylem?

• supporting the plant

• transporting amino acids

• transporting mineral ions

• transporting water

Answer explanation

The phloem transports sucrose and amino acids

Which word best completes the sentence? Water evaporates from the cells in the leaves and then diffuses out of the stomata

• epidermal

• guard

• mesophyll

• xylem

The diagrams show a transverse section through a root and a stem.

Which label on the diagram of the stem indicates the same tissue as X?

• A

• B

• C

• D

The diagram shows an experiment set up by a learner.

Which sequence shows the order of loss of mass by the leaves after one hour?

(in increasing order of loss of mass)

• P, Q, R, S

• Q, R, P, S

• R, Q, P, S

• S, P, Q, R

The diagram shows a plant that has had a ring of tissue removed from its stem .

After two days the concentration of sucrose at X was much greater than at Y.

What explains this?

• The phloem has been removed, so sucrose cannot move from the sink to the source.

• The phloem has been removed, so sucrose cannot move from the source to the sink.

• The xylem has been removed, so the water cannot move down the stem and transport the sucrose.

• The xylem has been removed, so the water cannot move up the stem and dilute the sucrose.

Answer explanation

Sucrose is transported by phloem from the source to the sink. In this case, the source is the leaves and the sink is the stem.

a. The tissue that transports water from the roots to the leaves is the

(a)  

b. A student set up the apparatus shown in the diagram.

The student recorded the position of the air bubble every two minutes for ten minutes. She then switched on a fan and recorded and recorded the position every two minutes for the next ten minutes.

The table shows her results.

Explain why the air bubble moved up the capillary tube.

Answer explanation

Water was lost from the leaves by transpiration pulling water up the capillary tube

c. With no fan, the mean rate of movement of the bubble was 1.7mm per minute.

Calculate the mean rate of movement of the bubble with the fan blowing. Show your working.

d. State one factor, other than wind speed, that could increase the rate of movement of the bubble.

Answer explanation

temperature; higher

or

humidity; lower