to reach sunlight , the most useful initial growth movement for a tropical vine presumably would be
Answers
1
1) All of the following may function in signal transduction in plants except
A) calcium ions.
B) nonrandom mutations.
C) receptor proteins.
D) phytochrome.
E) secondary messengers.
Answer: B
2
2) External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the
A) plasma membrane.
B) cytoplasmic matrix.
C) endoplasmic reticulum.
D) nuclear membrane.
E) nucleoplasm.
Answer: A
3
3) What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?
A) Specific protein kinase 1 would be activated, and greening would occur.
B) Ca2+ channels would not open, and no greening would occur.
C) Ca2+ channels could open, and specific protein kinase 2 could still be produced.
D) No transcription of genes that function in de-etiolation would occur.
E) Transcription of de-etiolation genes in the nucleus would not be affected.
Answer: C
4
4) If protein synthesis was blocked in etiolated cells, what would be necessary for the "greening" of these cells?
A) reception of light by phytochrome
B) activation of protein kinase 1 by cAMP
C) activation of protein kinase 2 by Ca2+
D) post-translational modification of existing proteins
E) 100-fold decrease in cytosolic Ca2+ levels
Answer: D
5
5) The detector of light during de-etiolation (greening) of a tomato plant is (are)
A) carotenoids.
B) xanthophylls.
C) phytochrome.
D) chlorophyll.
E) auxin.
Answer: C
6
6) Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the
A) tip of the coleoptile.
B) part of the coleoptile that bends during the response.
C) base of the coleoptile.
D) cotyledon.
E) phytochrome in the leaves.
Answer: A
7
7) Plants growing in a partially dark environment will grow toward light in a response called phototropism. Which of the following statements is true regarding phototropism?
A) It is caused by an electrical signal.
B) One chemical involved is ethylene.
C) Auxin causes a growth increase on one side of the stem.
D) Auxin causes a decrease in growth on the side of the stem exposed to light.
E) Removing the apical meristem enhances phototropism.
Answer: C
8
8) Which of the following conclusions is supported by the research of both Went 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) Agar contains a chemical substance that mimics a plant hormone.
C) A chemical substance involved in shoot bending is produced in shoot tips.
D) Once shoot tips have been cut, normal growth cannot be induced.
E) Light stimulates the synthesis of a plant hormone that responds to light.
Answer: C
9
9) We know from the experiments of the past that plants bend toward light because
A) they need sunlight energy for photosynthesis.
B) the sun stimulates stem growth.
C) cell expansion is greater on the dark side of the stem.
D) auxin is inactive on the dark side of the stem.
E) phytochrome stimulates florigen production.
Answer: C
10
10) Which of the following is a major mechanism whereby hormones control plant development?
A) cell respiration via regulation of the citric acid cycle
B) cell division via the cell cycle
C) cell elongation through production of cellulase
D) cell differentiation through altered spliceosome activity
E) cell synthesis of proteins via altered gene expression
Answer: B