Plant Structure Practice Questions

State two substances that are absorbed from the soil by root hair cells.

Explain how the shape of the root hair cell shown in Figure 1 helps the plant to take up water quickly.

Name the structures labelled A and B on Figure 2.

Give the letter of the cell that controls the opening and closing of the stoma.

State the function of structure A.

Complete the table by writing xylem or phloem next to each description.

The companion cells next to phloem sieve tubes contain large numbers of mitochondria.

Explain why.

Explain how the structure of xylem vessels is adapted to transport water up the plant.

Calculate the mean number of stomata per field of view for the lower surface of the leaf.

Use your answer to part (a) to calculate the number of stomata per $\text{mm}^2$ on the lower surface of the leaf.

On a hot, dry day the stomata of the holly leaves close.

Explain how the guard cells close a stoma and why this is useful to the plant.

Explain why the leaves of most plants are broad and thin.

Explain how the palisade mesophyll and the spongy mesophyll are each adapted to their function in the leaf.

Explain how having leaves reduced to spines helps the cactus to survive in a desert.

Explain how the thick waxy cuticle on the stem is an adaptation to a hot, dry environment.

Suggest an advantage to the cactus of opening its stomata at night rather than during the day.

A leaf is an organ made up of several different tissues.

Explain how the structure of a leaf is adapted for photosynthesis and for gas exchange.

One of these species grows in a hot desert and one has leaves that float on the surface of a pond.

Use the data in the table to identify each of these two species and explain your choices.

Species B has far fewer stomata per $\text{mm}^2$ than species A.

Explain one advantage and one disadvantage of this to species B.