You observe a houseplant on your window sill bending toward the bright afternoon sunlight. Being knowledgeable, you wish to explain the molecular events of the phototropic response to your friend. What is the correct sequence that you would describe?
I. PHOT1 attains a phosphate group and changes shape.
II. Cell elongation occurs on the shady side of the plant.
III. Auxin binds its receptor at target tissues.
IV. Light strikes PHOT1.
V. PHOT1 stimulates downward auxin transport on the shady side of the plant.
VI. Light strikes stomata, which close to minimize water loss.
VII. Cells on the illuminated side of the plant become shorter.

Question

Quizplus · Accepted Answer

The correct sequence for the molecular events in the phototropic response is: 
1) Light strikes PHOT1
2) PHOT1 attains a phosphate group and changes shape.
3) PHOT1 stimulates downward auxin transport on the shady side of the plant.
4) Auxin binds its receptor at target tissues.
5) Cell elongation occurs on the shady side of the plant.
Therefore, the correct sequence is C: IV, I, V, III, II. Choices A, B, and D have incorrect sequences of events. Option E is not correct since there is a specific sequence of events involved in the phototropic response.

You Observe a Houseplant on Your Window Sill Bending Toward