Deck 38: Plant Signals and Responses to the Environment

Question 1

Which plant hormones would be used by commercial grape growers to get larger grapes by lengthening the stem on which fruits develop?

A)abscisic acids
B)ethylenes
C)auxins
D)gibberellins

Answer 1

D

Question 2

Work by Charles Darwin and Francis Darwin was instrumental in the discovery of which plant hormones?

A)auxins
B)brassinosteroids
C)cytokinins
D)gibberellins

Answer 2

A

Question 3

What is the most widely used herbicide in the world, 2,4-D, a synthetic form of?

A)ethylene
B)salicylic acid
C)gibberellin
D)auxin

Answer 3

D

Question 4

Where is the auxin receptor ABP1 located in plant cells?

A)in the cell wall
B)in the cytoplasm
C)in the endoplasmic reticulum
D)in the plasma membrane

Question 5

Which of the following statements best describes the movement of IAA in a shoot tip?

A)IAA initially moves laterally from the shoot tip via polar transport.
B)IAA initially moves laterally from the shaded to illuminated side of the shoot tip.
C)IAA initially moves laterally from the illuminated to shaded side of the shoot tip.
D)IAA initially moves laterally from the shoot tip via nonpolar transport.

Question 6

What did Darwin's experiments on phototropism illustrate?

A)that signals from plant roots control phototropism
B)that an opaque cap placed over a shoot tip will cause a plant to bend toward light, but will inhibit growth
C)that a translucent cap placed over a shoot tip will cause a plant to bend toward light, but will inhibit growth
D)that a translucent cap placed over a shoot tip will cause a plant to both grow and bend toward light

Question 7

An agar block filled with auxin is placed on top of a shoot that has had the shoot tip removed. The agar block is placed so that it covers only one side of the top of the shoot. Which of the following should occur?

A)The shoot will stop growing.
B)The shoot will grow faster on the side away from the agar block.
C)The shoot will grow straight up.
D)The shoot will grow faster on the side with the agar block.

Question 8

Where is the growth-promoting substance that promotes stem elongation and bending toward light primarily produced?

A)in root tips, travelling to the stem in the xylem
B)in the centre of the stem region where elongation or bending occurs
C)in flowers and flower buds
D)in the shoot tip

Question 9

Imagine that you want all of the orange trees in your orchard to uniformly flower and set fruit. Which type of plant hormone should you spray on your plants?

A)brassinosteroid
B)auxins
C)ethylene
D)salicylic acid

Question 10

What are the usual concentrations of plant hormones that are effective, and what kind of effects do they have on different plant tissues?

A)They are effective only in extremely large concentrations, and they have the same effect on different plant tissues.
B)They are effective at low concentrations, and they have different effects on different plant tissues.
C)They are effective at low concentrations, and they have the same effect on different plant tissues.
D)They are effective only in extremely large concentrations, and they have different effects on different plant tissues.

Question 11

Which of the following is NOT known to be influenced by plant hormones?

A)plant cell metabolism
B)plant gene expression
C)plant growth response to light
D)plant extinction rate

Question 12

Which hormone's reduction in its amount causes a bush to become more bushy (have more lateral growth) after trimming a shrub?

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

Question 13

Which plant hormones are primarily responsible for helping break the dormancy of seeds and buds?

A)gibberellins
B)cytokinins
C)ethylenes
D)auxins

Question 14

Which of the following is the most important natural auxin?

A)abscisic acid
B)gibberellic acid
C)jasmonic acid
D)indoleacetic acid

Question 15

Which type of plant hormone is primarily responsible for inhibiting growth of lateral meristems on shoots and restricting the formation of branches?

A)abscisic acid
B)cytokinin
C)auxins
D)salicylic acid

Question 16

Which of the following should prevent a grass seedling shoot from bending toward light?

A)placing a translucent cap on the shoot tip
B)placing an opaque cap on the shoot tip
C)either removing the shoot tip or placing a translucent cap on the shoot tip
D)either removing the shoot tip or placing an opaque cap on the shoot tip

Question 17

Which type of plant hormone is primarily responsible for the bending of a plant shoot toward light?

A)auxin
B)ethylene
C)brassinosteroid
C) systemin

Question 18

Which plant hormone is primarily responsible for inhibiting leaf abscission?

A)ethylene
B)jasmonate
C)abscisic acid
D)auxin

Question 19

Creosote bush clusters have been shown to be descendant from single seeds. When did these seeds germinate?

A)5000 to 9000 years ago
B)9000 to 11000 years ago
C)when asexual reproduction occurred
D)when sexual reproduction occurred

Question 20

Which plant hormones are primarily responsible for promoting the formation of lateral roots?

A)jasmonates
B)gibberellins
C)auxins
D)systemin

Question 21

Which plant hormones were first discovered in experiments to define the nutrient media required for plant tissue culture?

A)gibberellins
B)cytokinins
C)salicylic acids
D)auxins

Question 22

According to the acid-growth hypothesis, auxin causes increased acidity in cell walls and disrupts bonds between cellulose microfibrils, allowing cell expansion. Which of the following does auxin activate for this to occur?

A)a membrane potential
B)AUX1 transporters
C)proteins called expansins
D)K⁺ ions

Question 23

Which plant hormones can be produced by boiling DNA?

A)salicylic acids
B)auxins
C)cytokinins
D)abscisic acids

Question 24

Which plant hormones are synthesized mainly in root tips and are apparently transported through the plant in xylem sap?

A)gibberellins
B)auxinsc ethylenes
C)cytokinins

Question 25

Suppose you are culturing tobacco in a petri dish at a 10:1 ratio of auxin to cytokinin. What would you do in order to promote only shoot development?

A)increase the cytokinin ratio
B)increase the auxin ratio
C)reduce the auxin level significantly and increase the cytokinin level slightly
D)grow the tobacco in the dark

Question 26

Which type of plant hormone retards leaf aging?

A)salicylic acid
B)abscisic acid
C)cytokinin
D)ethylene

Question 27

Which type of plant hormone promotes fruit ripening?

A)ethylene
B)jasmonate
C)gibberellin
D)brassinosteroid

Question 28

Which plant hormones cause chloroplasts to mature?

A)cytokinins
B)salicylic acids
C)abscisic acids
D)ethylenes

Question 29

A pea plant that is not able to make GA₁ will do which of the following?

A)grow away from light
B)not be able to make flowers
C)become a dwarf
D)not be able to make fruits

Question 30

How does the application of gibberellin affect monoecious species of plants (plants that have separate "male" and "female" flowers both on the same plant)?

A)It causes all flowers formed to be "female."
B)It encourages proportionately more "male" flowers to develop.
C)It causes all flowers formed to actually be both "male" and "female."
D)It causes all flowers formed to be "male."

Question 31

Placing a ripe apple with other apples that are not ripe will cause the other apples to ripen sooner. Which type of plant hormone is responsible for this effect?

A)brassinosteroid
B)ethylene
C)auxin
D)oligosaccharine

Question 32

Which plant hormones are primarily responsible for the growth of a floral stalk in rosette plants such as cabbages?

A)salicylic acids
B)cytokinins
C)ethylenes
D)gibberellins

Question 33

Which plant hormones appear to regulate the expression of genes associated with a plant's growth responses to light?

A)salicylic acids
B)brassinosteroids
C)gibberellins
D)jasmonates

Question 34

What is required in tobacco tissue culture to get both roots and shoots to develop?

A)an auxin-to-cytokinin ratio of 10:1
B)a higher concentration of cytokinin than auxin
C)an auxin-to-cytokinin ratio of slightly greater than 10:1
D)an intermediate auxin-to-cytokinin ratio

Question 35

Which type of plant hormone is a gas at normal temperature and pressure?

A)abscisic acid
B)ethylene
C)auxin
D)salicylic acid

Question 36

Synthetic compounds similar to which plant hormones are used to prolong the shelf life of vegetables such as lettuces and mushrooms and to keep cut flowers fresh?

A)jasmonates
B)abscisic acids
C)gibberellins
D)cytokinins

Question 37

Which type of plant hormone has been shown to both promote pollen tube elongation and inhibit root elongation?

A)jasmonate
B)ethylene
C)brassinosteroid
D)salicylic acid

Question 38

Which plant hormones were first isolated from the pollen of Brassica napus?

A)auxins
B)jasmonates
C)gibberellins
D)brassinosteroids

Question 39

Which plant hormones are structurally similar to adenine?

A)brassinosteroids
B)abscisic acids
C)ethylenes
D)cytokinins

Question 40

Which type of plant hormone governs senescence in plants, such as the loss of leaves in autumn by some plants?

A)abscisic acid
B)gibberellin
C)brassinosteroid
D)ethylene

Question 41

Where are abscisic acid receptors located in plant cells?

A)in the cell wall
B)in the cytoplasm
C)in the endoplasmic reticulum
D)in the plasma membrane

Question 42

Which type of plant hormone is generally responsible for long-term inhibition of plant growth such as in buds and seeds?

A)gibberellin
B)oligosaccharine
C)brassinosteroid
D)abscisic acid

Question 43

Which of the following types of plant hormones is apparently synthesized from carotenoid pigments inside plastids?

A)salicylic acid
B)cytokinins
C)abscisic acid
D)jasmonate

Question 44

After a plant has survived a microbial invasion, the rest of the plant is often less vulnerable to future infections. What is this called?

A)systemic acquired resistance
B)wound defense
C)gene-for-gene recognition
D)hypersensitive response

Question 45

What are chitinases examples of?

A)systemins
B)phytoalexins
C)PR proteins
D)R genes

Question 46

In systemic acquired resistance, the regulatory protein NPR-1 moves from the cytoplasm to the cell nucleus. What is this a consequence of?

A)a buildup of brassinosteroids in the cytoplasm
B)a buildup of oligosaccharins in the cytoplasm
C)a buildup of jasmonates in the cytoplasm
D)a buildup of salicylic acid in the cytoplasm

Question 47

When a plant has a hypersensitive response, which production triggers effects such as the expression of PR proteins?

A)the production of oligosaccharins
B)the production of salicylic acid
C)the production of ethylene
D)the production of cytokinin

Question 48

Imagine that you own a nursery and you want to reduce the chance that plants you ship will suffer from shipping damage. Which type of plant hormone should you apply to the plants before shipping?

A)cytokinin
B)abscisic acid
C)oligosaccharin
D)gibberellin

Question 49

Which of the following types of plant hormones trigger(s) plant responses to environmental stresses such as cold snaps, high salinity, and drought?

A)abscisic acid
B)cytokinins
C)oligosaccharins
D)jasmonates

Question 50

What are statoliths (particles that move in the direction gravity pulls them) typically in plants?

A)amyloplasts
B)calcium carbonate crystals
C)nuclei
D)vacuoles

Question 51

Why are secondary metabolites termed "secondary"?

A)because they are synthesized as part of basic metabolism
B)because they are only synthesized in plant leaves
C)because they are synthesized as precursors to primary metabolism
D)because they are not synthesized in all plant cells as part of basic metabolism

Question 52

Which synthesis is triggered when cells bind systemin?

A)gibberellin
B)auxin
C)jasmonate
D)cytokinin

Question 53

Which of the following triggers stomatal closure by involving the second messenger inositol triphosphate (IP₃)?

A)auxin
B)abscisic acid
C)oligosaccharin
D)salicylic acid

Question 54

What are secondary metabolites that function to protect plants from viral, fungal, and bacterial pathogens?

A)systemins
B)phytoalexins
C)PR proteins
D)R genes

Question 55

Which type of plant signalling molecule is similar in structure to aspirin?

A)abscisic acid
B)ethylene
C)salicylic acid
D)jasmonate

Question 56

Which type of plant hormone stimulates stomata to close during a drought?

A)salicylic acid
B)gibberellin
C)abscisic acid
D)auxin

Question 57

Light of which wavelengths is the main stimulus for phototropism?

A)red
B)green
C)yellow
D)blue

Question 58

Which plant signalling compounds are produced from structural elements of the cell wall?

A)salicylic acids
B)oligosaccharins
C)abscisic acids
D)auxins

Question 59

Which of the following are chaperone-type proteins that stabilize other proteins in response to environmental stresses such as salinity, drought, heat, and cold?

A)phytoalexins
B)PR proteins
C)R genes
D)heat-shock proteins

Question 60

Which of the following was the first peptide hormone discovered in plants that functions in wound response in the tomato?

A)cytokinin
B)systemin
C)gibberellin
D)salicylic acid

Question 61

Which type of plant hormone appears to play a major role in gravitropism in roots and shoots?

A)salicylic acid
B)gibberellin
C)abscisic acid
D)auxin

Question 62

Which of the following would probably NOT promote dormancy in at least some plants?

A)nitrogen deficiency
B)long nights
C)cold nights
D)warm nights

Question 63

Which of the following serves as a switching mechanism in the photoperiodic response in plants?

A)phytochrome
B)auxin
C)cryptochrome
D)calmodulin

Question 64

What happens with P_r and P_fr at night (assuming no artificial lights)?

A)P_r absorbs far-red light and is converted to P_fr.
B)P_fr absorbs red light and is converted to P_r.
C)P_fr absorbs far-red light and is converted to P_r.
D)P_fr is converted to P_r.

Question 65

Some signalling chemicals, such as oligosaccharins, are only synthesized when a tissue is damaged.

Question 66

Chrysanthemums are short-day plants, requiring a night length of longer than 12 hours to flower. Under which of the following conditions should chrysanthemums flower?

A)night length 14 hours, day length 10 hours
B)night length 10 hours, day length 14 hours
C)night length 14 hours, day length 10 hours; night interrupted in the middle by an intense red flash
D)night length 10 hours, day length 14 hours; day interrupted in the middle by half an hour of darkness

Question 67

What does P_r primarily absorb during daylight hours?

A)P_r absorbs red light and is converted to P_fr.
B)P_r absorbs far-red light and is converted to P_fr.
C)P_fr absorbs red light and is converted to P_r.
D)P_fr absorbs far-red light and is converted to P_r.

Question 68

How might a plant communicate to another plant that it has been attacked by a herbivore?

Question 69

Explain the hypersensitive response.

Question 70

What is thigmotropism a growth response to?

A)light
B)day length
C)contact with a solid object
D)circadian rhythms

Question 71

What do we call plant responses to the relative lengths of light and dark periods in their environment during each 24-hour period?

A)gravitropisms
B)photoperiodisms
C)thigmotropisms
D)phototropisms

Question 72

Describe the various effects of auxins in plants.

Question 73

Which of the following correctly describes the patterns of flowering in bearded irises and chrysanthemums?

A)Bearded irises flower when the night is shorter than a critical length, and chrysanthemums also flower when the night is shorter than a critical value.
B)Bearded irises flower when the night is longer than a critical length, and chrysanthemums also flower when the night is longer than a critical value.
C)Bearded irises flower when the night is longer than a critical length, whereas chrysanthemums flower when the night is shorter than a critical value.
D)Bearded irises flower when the night is shorter than a critical length, whereas chrysanthemums flower when the night is longer than a critical value.

Question 74

Charles Darwin was the first person to discover the hormone auxin.

Question 75

Which of the following terms describes plant activities that follow a biological clock so that they are based on cycles of about 24 hours?

A)gravitropisms
B)photoperiodisms
C)thigmotropisms
D)circadian rhythms

Question 76

Specific cells in developing seeds and maturing fruits have receptors for ethylene, but cells in stems generally do not.

Question 77

What is the exposure of plants to low temperatures (in order to stimulate flowering) called?

A)cryptotropism
B)thigmotropism
C)vernalization
D)florigen

Question 78

A plant hormone has the same effect in different plant tissues.

Question 79

You observe a sunflower that moves its leaves so that it tracks the sun across the sky throughout the day, and a sensitive plant that reversibly folds up its leaflets when you touch it. What are both of these examples of?

A)phototropism
B)thigmotropism
C)circadian rhythms
D)nastic movements

Question 80

If you were to start growing roses commercially, where would you probably want to set up your business?