Plant Responses

Question 1

State one hormone that promotes the ripening of fruit.

Answer 1

Ethene

Question 2

What is the normal action of IAA in plant cells?

Answer 2

Stimulates Cell elongation

Question 3

The herbicide atrazine disables one of the proton pumps in photosystem II.
Explain how atrazine would kill a susceptible plant.

Answer 3

Reduced proton pumping so photophosphorylation stops.
So less ATP produced and less NADP produced
So no Calvin cycle, so no hexose sugars

Question 4

Gibberellin causes an increase in the distance between the leaves on the stem, which is known as the internodal length.
Explain why gibberellin is classed as a plant hormone.

Answer 4

gibberellin is a chemical messenger, which is produced in one part of a plant and effects activity in another part. It is wide spread effect.

Question 5

Gibberellin causes an increase in internodal length. State one other role of gibberellin in plants.

Answer 5

Seed germination

Question 6

Give two examples of the commercial uses of auxin

Answer 6

Weed Killers
Promoting fruit ripening