Hormones and Growth

Question 1

phototropism

Answer 1

plants grow their shoots towards light sources

Question 2

plant hormones

Answer 2

an organic compound that acts as a chemical signal, eliciting a variety of responses that regulate growth and development; effective in extremely small amounts and may have multiple effects.

Question 3

auxin

Answer 3

any chemical substance that promotes seeding elongation to a point; then may inhibit growth

Question 4

cytokinin

Answer 4

growth regulators promoting cell division;

Question 5

eythlene

Answer 5

triggers fruit ripening and speeds up aging

Question 6

Gibberellin (Gibberellic acid - GA)

Answer 6

Promote stem elongation; synthesized in mainly roots and young leaves; ex very tall plants, bigger fruits(with axin)

Question 7

abscisic acid (ABA)

Answer 7

prevents seeds from germination in some plants; allows plants to survive harsh conditions; ex. drought, winter

Question 8

During winter periods of drought, which one of the following plant hormones inhibits growth and seed germination?

Answer 8

Abscisic acid

Question 9

In the autumn, the amount of …. increases and …. decreases in fruit and leaf stalks causing a plant to drop fruits and leaves

Answer 9

ethylene … auxin

Question 10

auxin causes a shoot to bend toward light by

Answer 10

stimulating growth on the lighted side of the shoot

Question 11

Which of the follwing is commercially used to stimulate the uniform ripening of bananas?

Answer 11

ethylene

Question 12

Which of the following is used to produce Thompson seedless grapes?

Answer 12

gibberlin

Question 13

According to the direct inhibition hypothesis, the status of auxillary buds depends on the relative concentrations of …. moving down from the shoot tip and ….. moving up from the roots.

Answer 13

auxin cytokinins