Plant Sensory Systems and Responses

Review Questions

The main photoreceptor that triggers phototropism is a ________.

  1. phytochrome
  2. cryptochrome
  3. phototropin
  4. carotenoid

Hint:

C

Phytochrome is a plant pigment protein that:

  1. mediates plant infection
  2. promotes plant growth
  3. mediates morphological changes in response to red and far-red light
  4. inhibits plant growth

Hint:

C

A mutant plant has roots that grow in all directions. Which of the following organelles would you expect to be missing in the cell?

  1. mitochondria
  2. amyloplast
  3. chloroplast
  4. nucleus

Hint:

B

After buying green bananas or unripe avocadoes, they can be kept in a brown bag to ripen. The hormone released by the fruit and trapped in the bag is probably:

  1. abscisic acid
  2. cytokinin
  3. ethylene
  4. gibberellic acid

Hint:

C

A decrease in the level of which hormone releases seeds from dormancy?

  1. abscisic acid
  2. cytokinin
  3. ethylene
  4. gibberellic acid

Hint:

A

A seedling germinating under a stone grows at an angle away from the stone and upward. This response to touch is called ________.

  1. gravitropism
  2. thigmonasty
  3. thigmotropism
  4. skototropism

Hint:

C