Question 1

________ are chemical substances produced in small quantities in one part of an organism and then transported to another part of the organism,where they bring about physiological responses.

Accepted Answer

A) Glycoproteins 
B) Photosynthates 
C) Hormones 
D) Heat shock proteins 
E) Pulvini

Question 2

How do heat shock proteins protect plants from high temperatures?

Accepted Answer

A) Heat shock proteins stabilize other proteins so that they don't denature at higher temperatures. 
B) Heat shock proteins prevent carbohydrates from being hydrolized at higher temperatures. 
C) Heat shock proteins prevent the double helix of DNA molecules from unwinding at higher temperatures. 
D) Heat shock proteins prevent lipids from dissolving at higher temperatures.

Question 3

When seeds are removed from strawberries,fruit growth is stopped.This suggests the seeds contain which of the following hormones?

Accepted Answer

A) ethylene 
B) auxin 
C) strigolactones 
D) oligosaccharides 
E) gibberellins

Question 4

A compound similar to auxin,2,4,5-trichlorophenoxyacetic acid (2,4,5-T),has been used

Accepted Answer

A) as a fertilizer for corn and wheat. 
B) as a spray to promote flowering of pineapple. 
C) as an organic substitute for chlorine bleach. 
D) to detoxify the dangerous poison dioxin. 
E) an herbicide for killing woody seedlings and dicot weeds.

Question 5

Several scientists,including Charles and Francis Darwin,Frits Went and others,demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments.Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

Accepted Answer

A) Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem,and thus a bending in the direction of the light. 
B) The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light. 
C) Auxin concentration was equal on both sides (lighted and shaded)of the stem; however,the apical meristem responded to the presence of light. 
D) A combination of positive phototropism and a negative gravitropism. 
E) The stems actually were responding to the agar blocks that had been used in the experiments.

Question 6

Which cell structure is most likely responsible for sensing gravity?

Accepted Answer

A) central vacuole 
B) Golgi apparatus 
C) chloroplast 
D) amyloplast 
E) apical meristem

Question 7

Coconut milk was an extremely useful additive in plant tissue culture because,in addition to amino acids,it contains

Accepted Answer

A) auxins. 
B) gibberellins. 
C) cytokinins. 
D) ethylene. 
E) abscisic acid.

Question 8

The acid growth hypothesis links

Accepted Answer

A) oligosaccharins to pH changes. 
B) cytokinin to thigmonasty. 
C) auxin to cell wall expansion. 
D) gibberellin to root elongation. 
E) ethylene to leaf abscission.

Question 9

Directional,light-triggered plant development is known as

Accepted Answer

A) thigmotropism. 
B) phototropism. 
C) thigmonasty. 
D) photomorphogenesis. 
E) acid-growth movement.

Question 10

Red light and phytochrome are involved in which of the following plant growth responses? Check all that apply.

Accepted Answer

A) thigmotropic responses 
B) inhibition of seed germination 
C) elongation of etiolated shoots 
D) detection of crowding by neighboring plants

Question 11

In Arabidopsis plants,about 7% of its genome is devoted to processes tied to which molecule?

Accepted Answer

A) auxin 
B) ubiquitin 
C) rubisco 
D) phytochrome 
E) gibberellins

Question 12

Which of the following are true statements about gibberellins? Check all that apply.

Accepted Answer

A) They can restore normal growth and development in certain dwarf mutants. 
B) They inhibit amylase and other hydrolytic enzymes. 
C) They are produced in the apical regions of shoots and roots. 
D) They promote internode elongation. 
E) They hasten seed germination.

Question 13

The directional growth response of plants to touch is called

Accepted Answer

A) phototropism. 
B) gravitropism. 
C) thigmotropism. 
D) photoperiodism. 
E) thermotropism.

Question 14

The plant hormones known as ________ may have an evolutionary origin in the common ancestor to both plants and animals.

Accepted Answer

A) brassinosteroids 
B) oligosaccharides 
C) cytokinins 
D) auxins 
E) abscisic acids

Question 15

Mature plants may become ________ in dry or cold seasons in order to survive long periods that are unfavorable for growth.

Accepted Answer

A) dormant 
B) dehydrated 
C) photoperiodic 
D) thigmonastic 
E) gravitropic

Question 16

Abscisic acid synthesized in the root travels to different parts of the shoot where it regulates transpirational water loss.What is the most likely way that ABA travels from the root to the various locations within the shoot?

Accepted Answer

A) vessels and tracheids 
B) sieve tubes 
C) between cell walls 
D) from cell to cell through the plasmodesmata

Question 17

While flipping through an agriculture products catalog,you come across the following advertisement,"The Centralized Ripening System-makes large scale hormone distribution even easier!".What hormone does this product distribute?

Accepted Answer

A) auxin 
B) abscisic acid 
C) cytokinin 
D) ethylene 
E) gibberellin

Question 18

The elongation of stems is stimulated by

Accepted Answer

A) auxin only. 
B) gibberellin only. 
C) ethylene only. 
D) auxin and gibberellin. 
E) auxin and ethylene.

Question 19

Abscisic acid (ABA)is synthesized in the roots in response to decreased soil water potential.ABA then translocates to the leaves,where it rapidly alters the osmotic potential of guard cells.What effect would this have on the stomata and the process of transpiration?

Accepted Answer

A) The stomata would open thereby increasing the rate of transpiration. 
B) The stomata would open thereby decreasing the rate of transpiration. 
C) The stomata would close thereby decreasing the rate of transpiration. 
D) The stomata would close thereby increasing the rate of transpiration. 
E) The change in the stomata would have no effect on the rate of transpiration.

Question 20

A scientist is investigating a hormone response in rose bush stems by removing the apical meristems of the main stems.What is the most likely result of this experiment and what hormone is responsible?

Accepted Answer

A) New apical buds will develop under the influence of auxin. 
B) Larger,deeper roots will form under the influence of cytokinin. 
C) More leaf buds will appear along the main stems under the influence of auxin. 
D) Flowers will turn yellow and fall off under the influence of auxin. 
E) Lateral buds will develop under the influence of cytokinin.

Exam 39: Sensory Systems in Plants