Question 1

Which of the following best describes the process of phase change in plants as shown in the first image?

Accepted Answer

A transition from vegetative to reproductive growth, allowing the plant to become competent to flower.

Question 2

A plant that flowers only when the night is longer than a critical length is classified as which type of plant?

Accepted Answer

Short-day plant

Question 3

Which hormone is primarily responsible for inducing the triple response in seedlings, as shown in the image with the curved seedlings?

Accepted Answer

Ethylene

Question 4

In the context of fruit ripening, what is the climacteric phenomenon characterized by?

Accepted Answer

A sharp increase in respiration rate and ethylene production

Question 5

Which of the following is a correct equation for the chemical structure of ethylene?

Accepted Answer

$$\mathrm{C_2H_4}$$

Question 6

A tulip requires a period of cold before it can flower. Which flowering pathway does this requirement illustrate?

Accepted Answer

Temperature-dependent pathway (vernalization)

Question 7

Which gene is directly activated by gibberellin to promote flowering?

Accepted Answer

LFY

Question 8

Which of the following best explains why a day-neutral plant flowers?

Accepted Answer

It flowers when it reaches maturity, regardless of day length.

Question 9

Which process is delayed by the application of STS (silver thiosulfate) to cut flowers?

Accepted Answer

Senescence

Question 10

During leaf abscission, which enzyme is primarily responsible for breaking down the middle lamella in the separation layer?

Accepted Answer

Pectinase

Question 11

A researcher exposes a short-day plant to a long night, but interrupts the night with a brief flash of red light. What is the most likely outcome?

Accepted Answer

Flowering is inhibited because the critical night length is not met.

Question 12

Which of the following is NOT a characteristic of senescence in leaves?

Accepted Answer

Increase in chlorophyll content

Question 13

Which of the following treatments would most effectively delay fruit ripening during storage?

Accepted Answer

High concentration of CO$$_2 (3-5$$%)

Question 14

Which pathway to flowering is least dependent on environmental cues and more on internal signals?

Accepted Answer

Autonomous pathway

Question 15

Which of the following best describes the role of the abscission layer in leaf drop?

Accepted Answer

It forms at the base of the petiole and facilitates leaf separation through enzymatic breakdown of cell walls.

Question 16

Which of the following statements about the floral meristem identity genes LFY and AP1 is correct?

Accepted Answer

They activate floral organ identity genes, leading to the development of sepals, petals, stamens, and carpels.

Question 17

A mutation that prevents the breakdown of floral inhibitors would most likely result in which phenotype?

Accepted Answer

Delayed or absent flowering

Question 18

Which of the following fruits is classified as climacteric and will continue to ripen after harvest due to ethylene production?

Accepted Answer

Banana

Question 19

Which of the following best explains why autumn leaves change color before falling?

Accepted Answer

Chlorophyll breaks down, revealing carotenoids and allowing anthocyanins to accumulate.

Question 20

Which of the following is a multi-step process that integrates both hormonal and environmental cues to regulate flowering?

Accepted Answer

Activation of floral meristem identity genes by the combined action of gibberellin, light, temperature, and autonomous pathways.

Flowering Control, Fruit Ripening, and Senescence in Plants

Study Guide - Practice Questions