Botany MCQs
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Which of the following conclusions is supported by the research of both Peter Boysen-Jensen and Charles and Francis Darwin on shoot responses to light?
- A. When shoots are exposed to light, a chemical substance migrates toward the light.
- B. A chemical substance involved in shoot bending is produced in shoot tips.
- C. Once shoot tips have been cut, normal growth cannot be induced.
- D. Light stimulates the synthesis of a plant hormone that responds to light.
- Correct Answer: Option B
You are out working in your garden, and you notice that one of your favorite flowering plants has black, dead spots on the leaves. You immediately suspect that the plant has been invaded by a pathogen and has initiated a(n) ________.
- A. avirulence response
- B. hypersensitive response
- C. resistance response
- D. virulence response
- Correct Answer: Option B
In the fall, the leaves of some trees change color. This happens because chlorophyll breaks down and the accessory pigments become visible. What hormone is responsible for this?
- A. phototropin
- B. abscisic acid
- C. cytokinin
- D. ethylene
- Correct Answer: Option D
Who might be interested in using cytokinins?
- A. grocers, to spray on fruit to enhance ripening in the store
- B. consumers, to spray on fruit before eating to enhance taste
- C. florists, to dip stems in to keep leaves green longer
- D. farmers, to spray on fruit after picking to stall ripening
- Correct Answer: Option B
When an arborist prunes a limb off a valuable tree, he or she may paint the cut surface. The primary purpose of the paint is to ________.
- A. minimize water loss by evaporation from the cut surface
- B. improve the appearance of the cut surface
- C. stimulate growth of the cork cambium to "heal" the wound
- D. block entry of pathogens through the wound
- Correct Answer: Option D
Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?
- A. Auxin stimulates proton pumps in the plasma membrane and tonoplast.
- B. Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible.
- C. Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils.
- D. Auxins activate aquaporins that increase turgor pressure in the cells.
- Correct Answer: Option B
An eccentric millionaire botanist has offered a $25,000 scholarship to anyone who can successfully get a plant to grow through a vertical maze in complete darkness. The maze is not in a box; the maze is simply drawn on the wall, and the contestants must get their plant to grow in a pattern that matches the path through the maze. You need the money and feel confident that you can accomplish this task. Which of the following techniques will help you succeed?
- A. Apply auxin directly to the shoot tip on the side to which you want the tip to bend.
- B. Apply auxin directly to the part of the stem just below the tip opposite from the direction you want the stem to bend.
- C. Inject compounds that block auxin receptors into the part of the stem opposite from the direction you want the stem to bend.
- D. Plant the roots in two different pots, and apply auxin to the root bucket that is on the same side as the direction you want the plant to bend.
- Correct Answer: Option B
Which one of the following hormones regulates cell division in plants?
- A. auxin (IAA)
- B. ethylene
- C. gibberellins
- D. cytokinins
- Correct Answer: Option D
A gardener in Canada wants to surprise his mother on her birthday and make her favorite hibiscus bush flower in May instead of at the end of June. The bush is growing in the greenhouse. Which of the following might make the hibiscus bush flower early?
- A. grafting leaves of a hibiscus that was exposed to long nights
- B. grafting leaves of a hibiscus that was exposed to short nights
- C. exposing flower buds of the hibiscus bush to long nights
- D. exposing flower buds of the hibiscus bush to short nights
- Correct Answer: Option B
Which of the following mechanisms is the correct sequence of events that takes place during the plant responses to internal and external signals?
- A. transduction, reception, and response
- B. reception and transduction
- C. reception, transduction, and response
- D. reception and response
- Correct Answer: Option C