Plant responses and plant hormones Quiz
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5 questions, one answer each
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1. Which wavelength of light converts Pfr back to Pr?
- A. Red light (660 nm)
- B. Blue light
- C. Far-red light (730 nm)
- D. Green light
2. How does gibberellin allow transcription of target genes?
- A. By causing breakdown of DELLA proteins that inhibit transcription
- B. By acting as an RNA polymerase
- C. By digesting the cell wall
- D. By converting Pr into Pfr
3. What happens to the cell wall in the acid growth hypothesis?
- A. It becomes thicker and more alkaline
- B. It is digested to glucose
- C. It is rebuilt without cellulose
- D. H⁺ is pumped in, lowering the pH and activating expansins
4. Embryo-less half grains on starch agar with gibberellin produce a clear zone but those on water do not. What does this show?
- A. The embryo contains iodine
- B. Gibberellin stimulates the grain to produce amylase
- C. Starch is hydrolysed by gibberellin itself
- D. Water inhibits amylase
5. A short-day plant is given a brief red flash in the middle of a long night. Predict the effect on flowering.
- A. Flowering is stimulated because Pfr falls
- B. Flowering is prevented because Pfr is formed
- C. No effect, because red light is not absorbed
- D. Flowering is prevented because Pfr is converted to Pr