Question 1

Trace the steps that occur between the planting of a pea seed and the emergence of the pea plant.

Accepted Answer

The watering of the pea seed after plant

Question 2

A homeowner has installed an outdoor gas-burning grill on her back patio next to her favorite camellia bush. After the first few nights of using the grill, she notices that the camellia is beginning to lose its leaves. Which of the following is the best explanation for what is happening?

Accepted Answer

A)  The bush is getting too warm next to the grill. 
B)  Ethylene is a by-product of the burning gas and is causing senescence in the plant. 
C)  Abscisic acid is a by-product of the burning gas and is causing senescence in the plant. 
D)  The plant is a biennial and is bolting. 
E)  Auxin production is being inhibited. 
A)  The bush is getting too warm next to the grill. 
B)  Ethylene is a by-product of the burning gas and is causing senescence in the plant. 
C)  Abscisic acid is a by-product of the burning gas and is causing senescence in the plant. 
D)  The plant is a biennial and is bolting. 
E)  Auxin production is being inhibited.

Question 3

Plant hormones can work in pairs, with one hormone promoting a phenomenon and another inhibiting it. In the following list of plant hormones, the hormone named first stimulates and the second, inhibits. Which pair has opposing effects on senescence?

Accepted Answer

A)  Cytokinin and abscisic acid 
B)  Ethylene and cytokinin 
C)  Auxin and gibberellins 
D)  Ethylene and auxin 
E)  Brassinosteroids and auxin 
A)  Cytokinin and abscisic acid 
B)  Ethylene and cytokinin 
C)  Auxin and gibberellins 
D)  Ethylene and auxin 
E)  Brassinosteroids and auxin

Question 4

Based on your knowledge of the effects of cytokinins on plant growth and development, which of the following is the most likely phenotype of a plant that has been bioengineered to have elevated cytokinin synthesis. (Assume that the levels of other plant hormones are normal in the mutant strain.)

Accepted Answer

A)  The shoot system of the mutant plant is taller. 
B)  The formation of roots is greater in the mutant. 
C)  The mutant is more highly branched. 
D)  Leaf senescence is accelerated in the mutant. 
E)  None of the above 
A)  The shoot system of the mutant plant is taller. 
B)  The formation of roots is greater in the mutant. 
C)  The mutant is more highly branched. 
D)  Leaf senescence is accelerated in the mutant. 
E)  None of the above

Question 5

The adaptive advantage of seed dormancy is that it may

Accepted Answer

A)  result in germination at a favorable time. 
B)  increase the probability of a seed's germinating in the right place. 
C)  be a way to avoid competition. 
D)  result in an increase in the likelihood of dispersal. 
E)  All of the above 
A)  result in germination at a favorable time. 
B)  increase the probability of a seed's germinating in the right place. 
C)  be a way to avoid competition. 
D)  result in an increase in the likelihood of dispersal. 
E)  All of the above

Question 6

The growth of a plant cell is driven primarily by

Accepted Answer

A)  cytokinesis. 
B)  the uptake of water into the vacuole. 
C)  the strengthening of cell wall components. 
D)  the deposition of new cell wall materials on the outside of the cell wall. 
E)  the forces in transpirational pull. 
A)  cytokinesis. 
B)  the uptake of water into the vacuole. 
C)  the strengthening of cell wall components. 
D)  the deposition of new cell wall materials on the outside of the cell wall. 
E)  the forces in transpirational pull.

Question 7

In a classic experiment, a gelatin block containing auxin was placed on one edge of a decapitated coleoptile. The result was that the coleoptile

Accepted Answer

A)  grew straight up. 
B)  grew more on the side with the block. 
C)  grew more on the side away from the block. 
D)  grew a new coleoptile tip. 
E)  did not grow. 
A)  grew straight up. 
B)  grew more on the side with the block. 
C)  grew more on the side away from the block. 
D)  grew a new coleoptile tip. 
E)  did not grow.

Question 8

Which of the following triggers germination of a seed?

Accepted Answer

A)  The imbibing of water 
B)  Its release from the fruit 
C)  Chemical changes 
D)  The exclusion of water 
E)  All of the above 
A)  The imbibing of water 
B)  Its release from the fruit 
C)  Chemical changes 
D)  The exclusion of water 
E)  All of the above

Question 9

The gibberellins

Accepted Answer

A)  are responsible for phototropism and gravitropism. 
B)  are gases at room temperature. 
C)  are produced only by fungi. 
D)  cause flowering in plants. 
E)  inhibit the synthesis of digestive enzymes by barley seeds. 
A)  are responsible for phototropism and gravitropism. 
B)  are gases at room temperature. 
C)  are produced only by fungi. 
D)  cause flowering in plants. 
E)  inhibit the synthesis of digestive enzymes by barley seeds.

Question 10

As a seed germinates, DNA synthesis begins

Accepted Answer

A)  when gibberellins are secreted by the embryo. 
B)  when the embryonic root, or radicle, begins to grow. 
C)  as imbibition takes place. 
D)  when the endosperm starts metabolizing starches, proteins, and lipids. 
E)  when the aleurone layer assembles enzymes, proteases, and ribonucleases. 
A)  when gibberellins are secreted by the embryo. 
B)  when the embryonic root, or radicle, begins to grow. 
C)  as imbibition takes place. 
D)  when the endosperm starts metabolizing starches, proteins, and lipids. 
E)  when the aleurone layer assembles enzymes, proteases, and ribonucleases.

Question 11

Molecules that are active at small concentrations and regulate plant development are called _______.

Accepted Answer

The answer of Molecules that are active at small concentrations...

Question 12

Auxin promotes plant cell growth by

Accepted Answer

A)  enhancing cell division. 
B)  enhancing cell expansion. 
C)  thickening cell walls. 
D)  causing hydroxide ions to be released from the cells. 
E)  stimulating cytokinin synthesis. 
A)  enhancing cell division. 
B)  enhancing cell expansion. 
C)  thickening cell walls. 
D)  causing hydroxide ions to be released from the cells. 
E)  stimulating cytokinin synthesis.

Question 13

Gravitropism is the phenomenon by which a plant part grows

Accepted Answer

A)  toward the center of Earth. 
B)  in a direction determined by gravity. 
C)  in a direction opposite to that of the main light source. 
D)  in a direction opposite to that of the growth of the shoot. 
E)  toward the darkest area. 
A)  toward the center of Earth. 
B)  in a direction determined by gravity. 
C)  in a direction opposite to that of the main light source. 
D)  in a direction opposite to that of the growth of the shoot. 
E)  toward the darkest area.

Question 14

Signal transduction for both auxin and gibberellins involves

Accepted Answer

A)  binding of the hormone to a nuclear receptor. 
B)  degradation of a repressor of gene transcription. 
C)  production of a small molecule second messenger. 
D)  light absorption followed by chemical changes. 
E)  breakdown of the hormone. 
A)  binding of the hormone to a nuclear receptor. 
B)  degradation of a repressor of gene transcription. 
C)  production of a small molecule second messenger. 
D)  light absorption followed by chemical changes. 
E)  breakdown of the hormone.

Question 15

It is thought that auxins control growth by cell _______, whereas cytokinins cause growth by cell _______.

Accepted Answer

elongation

Question 16

To mobilize its nutrient reserves, a germinating barley seed

Accepted Answer

A)  becomes dormant. 
B)  undergoes senescence. 
C)  secretes gibberellins into its endosperm. 
D)  converts glycerol and fatty acids into lipids. 
E)  takes up proteins from the endosperm. 
A)  becomes dormant. 
B)  undergoes senescence. 
C)  secretes gibberellins into its endosperm. 
D)  converts glycerol and fatty acids into lipids. 
E)  takes up proteins from the endosperm.

Question 17

Which of the following is not involved in the acid growth hypothesis for the regulation of cell expansion by auxin?

Accepted Answer

A)  The pumping of protons into the cell wall 
B)  The pumping of protons into the cytosol 
C)  Increased gene expression of the proton pump gene 
D)  Increased insertion of proton pumps into the plasma membrane 
E)  All of the above are involved. 
A)  The pumping of protons into the cell wall 
B)  The pumping of protons into the cytosol 
C)  Increased gene expression of the proton pump gene 
D)  Increased insertion of proton pumps into the plasma membrane 
E)  All of the above are involved.

Question 18

A cell wall is a network of cross-linked _______ in a matrix of _______ fibers.

Accepted Answer

A)  cellulose molecules; starch 
B)  starches; polysaccharide 
C)  polysaccharides and proteins; cellulose 
D)  starches; nonpolysaccharide 
E)  cellulose molecules; protein 
A)  cellulose molecules; starch 
B)  starches; polysaccharide 
C)  polysaccharides and proteins; cellulose 
D)  starches; nonpolysaccharide 
E)  cellulose molecules; protein

Question 19

In plants that germinate in response to a brief pulse of light,

Accepted Answer

A)  green light is most effective in triggering germination. 
B)  far-red light is most effective in triggering germination. 
C)  far-red light reverses the effect of prior exposure to red light. 
D)  initiation of photosynthesis is the mechanism for germination. 
E)  a rise in temperature also triggers germination. 
A)  green light is most effective in triggering germination. 
B)  far-red light is most effective in triggering germination. 
C)  far-red light reverses the effect of prior exposure to red light. 
D)  initiation of photosynthesis is the mechanism for germination. 
E)  a rise in temperature also triggers germination.

Question 20

Charles Darwin was a brilliant researcher of plant biology who was far ahead of his time. His experiments on phototropism in seedlings of a grass plant

Accepted Answer

A)  established that the base of the coleoptile contained the photoreceptor for phototropism. 
B)  led Darwin and his son to hypothesize the existence of a growth-promoting substance in the coleoptile. 
C)  showed that the growing region of the coleoptile and the light-sensing area were the same. 
D)  showed that the tip of the coleoptile was not required for the phototrophic response. 
E)  showed that light has no effect on plant development. 
A)  established that the base of the coleoptile contained the photoreceptor for phototropism. 
B)  led Darwin and his son to hypothesize the existence of a growth-promoting substance in the coleoptile. 
C)  showed that the growing region of the coleoptile and the light-sensing area were the same. 
D)  showed that the tip of the coleoptile was not required for the phototrophic response. 
E)  showed that light has no effect on plant development.

Exam 37: Regulation of Plant Growth

Trace the steps that occur between the planting of a pea seed and the emergence of the pea plant.

A homeowner has installed an outdoor gas-burning grill on her back patio next to her favorite camellia bush. After the first few nights of using the grill, she notices that the camellia is beginning to lose its leaves. Which of the following is the best explanation for what is happening?

Plant hormones can work in pairs, with one hormone promoting a phenomenon and another inhibiting it. In the following list of plant hormones, the hormone named first stimulates and the second, inhibits. Which pair has opposing effects on senescence?

Based on your knowledge of the effects of cytokinins on plant growth and development, which of the following is the most likely phenotype of a plant that has been bioengineered to have elevated cytokinin synthesis. (Assume that the levels of other plant hormones are normal in the mutant strain.)

The adaptive advantage of seed dormancy is that it may

The growth of a plant cell is driven primarily by

In a classic experiment, a gelatin block containing auxin was placed on one edge of a decapitated coleoptile. The result was that the coleoptile

Which of the following triggers germination of a seed?

The gibberellins

As a seed germinates, DNA synthesis begins

Molecules that are active at small concentrations and regulate plant development are called _______.

Auxin promotes plant cell growth by

Gravitropism is the phenomenon by which a plant part grows

Signal transduction for both auxin and gibberellins involves

It is thought that auxins control growth by cell _______, whereas cytokinins cause growth by cell _______.

To mobilize its nutrient reserves, a germinating barley seed

Which of the following is not involved in the acid growth hypothesis for the regulation of cell expansion by auxin?

A cell wall is a network of cross-linked _______ in a matrix of _______ fibers.

In plants that germinate in response to a brief pulse of light,

Charles Darwin was a brilliant researcher of plant biology who was far ahead of his time. His experiments on phototropism in seedlings of a grass plant

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It is thought that auxins control growth by cell _, whereas cytokinins cause growth by cell _.

A cell wall is a network of cross-linked _ in a matrix of _ fibers.