Question 1

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

Accepted Answer

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. 
E) induce the production of phytoalexins.

Question 2

Oat seedlings are sometimes used to study auxins because

Accepted Answer

A) they are a readily accessible monocot, and auxins affect only monocots. 
B) they have a stiff coleoptile. 
C) they green rapidly in the light. 
D) their coleoptile exhibits a strong positive phototropism. 
E) monocots inactivate synthetic auxins.

Question 3

Ethylene, as an example of a plant hormone, may have multiple effects on a plant, depending on all of the following except the

Accepted Answer

A) site of action within the plant. 
B) developmental stage of the plant. 
C) concentration of ethylene. 
D) altered chemical structure of ethylene from a gas to a liquid. 
E) readiness of cell membrane receptors for the ethylene.

Question 4

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

Accepted Answer

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.

Question 5

Many plants flower in response to day-length cues. Which statement concerning flowering is False?

Accepted Answer

A) As a rule, short-day plants flower in the spring or fall. 
B) As a rule, long-day plants flower in the summer. 
C) Long-day plants flower in response to long days, not short nights. 
D) Flowering in day-neutral plants is not influenced by day length. 
E) Flowering in short-day plants is controlled by photochrome.

Question 6

Which of the following has not been established as an aspect of auxin's role in cell elongation?

Accepted Answer

A) Auxin instigates a loosening of cell wall fibers. 
B) Auxin increases the quantity of cytoplasm in the cell. 
C) Through auxin activity, vacuoles increase in size. 
D) Auxin activity permits an increase in turgor pressure. 
E) Auxin stimulates proton pumps.

Question 7

Unlike animal hormones, plant hormones are primarily involved in regulating growth and development.

Accepted Answer

A) True 
 B)False

Question 8

If protein synthesis was blocked in etiolated cells, what would be necessary for the "greening" of these cells?

Accepted Answer

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 Ca++ levels

Question 9

When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?

Accepted Answer

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

Question 10

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely

Accepted Answer

A) cause increased flower production. 
B) have no effect upon flowering. 
C) inhibit flowering. 
D) stimulate flowering. 
E) convert florigen to the active form.

Question 11

Plant hormones can have different effects at different concentrations. This explains how

Accepted Answer

A) some plants are long-day plants and others are short-day plants. 
B) signal transduction pathways in plants are different from those in animals. 
C) plant genes recognize pathogen genes. 
D) auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds. 
E) they really don't fit the definition of "hormone."

Question 12

The plant hormone involved in aging and ripening of fruit is

Accepted Answer

A) auxin. 
B) ethylene. 
C) florigen. 
D) abscisic acid. 
E) gibberellin.

Question 13

In extremely cold regions, woody species may survive freezing temperatures by

Accepted Answer

A) emptying water from the vacuoles to prevent freezing. 
B) decreasing the numbers of phospholipids in cell membranes. 
C) decreasing the fluidity of all cellular membranes. 
D) producing canavanine as a natural antifreeze. 
E) increasing cytoplasmic levels of specific solute concentrations, such as sugars.

Question 14

Which hormone is incorrectly paired with its function?

Accepted Answer

A) auxin-promotes stem growth through cell elongation 
B) cytokinins-initiate programmed cell death 
C) gibberellins-stimulate seed germination 
D) abscisic acid-promotes seed dormancy 
E) ethylene-inhibits cell elongation

Question 15

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that produces a guard cell hormone under water-deficit conditions. Most likely the hormone is

Accepted Answer

A) ABA. 
B) GA. 
C) IAA. 
D) 2, 4-D. 
E) salicylic acid.

Question 16

Systemic acquired resistance is a generalized plant defense response in organs distant from the infection site.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following statements about plant hormones is False?

Accepted Answer

A) The growth of plants in nature is probably regulated by a combination of growth-stimulating and growth-inhibiting hormones. 
B) Abscisic acid generally promotes growth. 
C) Gibberellins stimulate cell enlargement. 
D) Cytokinins promote cell division. 
E) Ethylene contributes to the aging of plants.

Question 18

Bald cypress and Loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

Accepted Answer

A) There are larger intercellular spaces in the roots of the cypress than in the roots of the pine. 
B) Water-conducting cells are larger in the stems of the cypress than in the stems of the pine. 
C) The springwood and summerwood are more distinct in the cypress. 
D) There is less parenchyma in the roots of the cypress than in the pine roots. 
E) There are no major anatomical differences between these species because they're both gymnosperms.

Question 19

Most scientists agree that global warming is underway; thus it is important to know how plants respond to heat stress. Which of the following is an immediate short-term response of plants to heat stress?

Accepted Answer

A) the production of heat-shock carbohydrates unique to each plant 
B) the production of heat-shock proteins like those of other organisms 
C) the opening of stomata to increase evaporational heat loss 
D) their evolution into more xerophytic plants 
E) all of the above

Question 20

What does a short-day plant need in order to flower?

Accepted Answer

A) a burst of red light in the middle of the night 
B) a burst of far-red light in the middle of the night 
C) a day that is longer than a certain length 
D) a night that is longer than a certain length 
E) a higher ratio of Pr to Pfr.

Exam 39: Plant Responses to Internal and External Signals

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

Oat seedlings are sometimes used to study auxins because

Ethylene, as an example of a plant hormone, may have multiple effects on a plant, depending on all of the following except the

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

Many plants flower in response to day-length cues. Which statement concerning flowering is False?

Which of the following has not been established as an aspect of auxin's role in cell elongation?

Unlike animal hormones, plant hormones are primarily involved in regulating growth and development.

If protein synthesis was blocked in etiolated cells, what would be necessary for the "greening" of these cells?

When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely

Plant hormones can have different effects at different concentrations. This explains how

The plant hormone involved in aging and ripening of fruit is

In extremely cold regions, woody species may survive freezing temperatures by

Which hormone is incorrectly paired with its function?

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that produces a guard cell hormone under water-deficit conditions. Most likely the hormone is

Systemic acquired resistance is a generalized plant defense response in organs distant from the infection site.

Which of the following statements about plant hormones is False?

Bald cypress and Loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

Most scientists agree that global warming is underway; thus it is important to know how plants respond to heat stress. Which of the following is an immediate short-term response of plants to heat stress?

What does a short-day plant need in order to flower?