Deck 26: Flowering Plants: Control of Growth Responses

Question 1

Which of the following plant hormones was discovered in infected rice seedlings that grew extremely tall and slender with "foolish seedling disease"?

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

Answer 1

E

Question 2

Which of the following plant hormones is associated with the closure of stomata when a plant experiences water stress?

A)abscisic acid
B)auxin
C)cytokinin
D)gibberellins

Answer 2

A

Question 3

Which statement about plant hormones is NOT true?

A)Plant hormones include at least one form that is a gas.
B)Each naturally occurring hormone has a specific chemical structure.
C)Hormones are among the principal internal regulators of plant growth.
D)Responses to plant hormones may be observed in nearly any part of a plant.
E)All known growth regulators of plants are chemicals produced naturally in plants.

Answer 3

E

Question 4

Which of the following plant hormones is used to prolong the life of flower cuttings and stored vegetables?

A)auxins
B)cytokinins
C)ethylene
D)IAA

Question 5

Which of the following plant hormones breaks dormancy in seeds and buds when applied to the plant?

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

Question 6

Which of the following pertain to movement of plants?

A)nastic movements
B)thigmotropism
C)phototropism
D)gravitropism
E)All of the choices are correct.

Question 7

Horticulturists often use ______ and other growth regulators applied as a paste to plant cuttings to stimulate root formation.

A)ethylene
B)abscisic acid
C)cytokinins
D)indolacetic acid (IAA)

Question 8

Which plant hormone produced in apical meristems inhibits the growth of axillary buds?

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

Question 9

The germinating corn seed pictured below is displaying

A)negative gravitropism.
B)positive gravitropism.
C)thigmotropism.
D)negative phototropism.
E)positive phototropism.

Question 10

A plant's response to an external stimulus involves receptors.A receptor that responds to light normally contains

A)a series of relay proteins.
B)a pigment component.
C)a transduction pathway.
D)an end product of a metabolic pathway.

Question 11

The general sequence by which a plant responds to external stimuli is

A)chloroplast-vascular bundle-sap.
B)reception-transduction-cellular response.
C)sensory nerve-interneuron-motor nerve.
D)input-reflex-output.
E)leaf-stem-root.

Question 12

Plant hormones are generally produced in _______ tissues.

A)cortical (cortex)
B)epidermal
C)meristematic
D)vascular
E)floral

Question 13

Removing the top of a plant to create fuller growth involves which of the following hormones?

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

Question 14

Which of the following plant hormones was studied in the 1880s by Charles and Francis Darwin in experiments on phototropism?

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

Question 15

Which of these external stimuli produce movement of a plant toward light?

A)negative gravitropism
B)positive gravitropism
C)thigmotropism
D)negative phototropism
E)positive phototropism

Question 16

Which of the following is a receptor that responds to light?

A)photochrome
B)phototropin
C)gibberellins
D)cytokinins
E)photochrome and phototropin are correct.

Question 17

Indoleacetic acid (IAA)is the most commonly occurring form of which of the following plant hormones?

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

Question 18

Which of the following ions is affected by gibberellins and is also involved in signal transduction?

A)H⁺
B)Ca²⁺
C)Na⁺
D)Mg²⁺

Question 19

______ is often referred to as the "stress" hormone since it initiates and maintains seed and bud dormancy.

A)Ethylene
B)Cytokinins
C)Abscisic acid
D)Gibberellins

Question 20

The vine in the picture below is displaying

A)negative gravitropism.
B)positive gravitropism.
C)thigmotropism.
D)negative phototropism.
E)positive phototropism.

Question 21

Figure: The cylinders in this experiment represent a 24-hour period.The light area represents light periods during a 24-hr.period and the dark area represents dark periods during a 24-hr.period.The critical length of dark vs.light periods for flowering is depicted by the dotted line.Note that some plants are flowering and some are not flowering.Study the results of this experiment on photoperiodism and flowering to determine whether the following statements are True or False.
Short-day plants flower when the day length is longer than the critical length.

Question 22

A chemical messenger from the embryo that stimulates a seed to digest the endosperm is

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

Question 23

Which of the following plant defense mechanisms is used in the commercial product asprin?

A)abscisic acid
B)auxin
C)jasmonic acid
D)salicylic acid
E)systemin

Question 24

Which of the following secondary metabolites are used by humans as medicines and also have the ability to block DNA & RNA synthesis in insects?

A)alkaloids
B)cyanogenic glycosides
C)tannins
D)proteinase inhibitors

Question 25

Which of the following plant hormones is associated with the closure of stomata in a plant under water stress?

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

Question 26

Plants could readily develop seasonal responses for flowering based on temperature changes but have "elected" through evolution to manage their rhythms based on a comparison of daylight and darkness.Why has the day-night ratio system been selected?

A)Temperature has no effect upon plant biochemistry.
B)Temperature is a gradation but day/night is all-or-nothing.
C)A plant's nervous system is tuned to light stimuli and not to temperature stimuli.
D)Temperatures fluctuate widely across seasons and from year to year,but photoperiod comparisons are a more reliable indicator of season.

Question 27

Which of the following is (are)an effect(s)of auxin?

A)Applied to a woody cutting,auxin causes roots to develop.
B)Auxin production by seeds promotes the growth of fruit.
C)Trees sprayed with auxin will keep mature fruit from falling to the ground.
D)Under the effect of gravity,auxin moves to the lower surface of roots and stems,causing roots to curve downward and stems to curve upward.
E)All of the choices are effects of auxin.

Question 28

How does gibberellin actually work?

A)In the presence of blue light,it triggers additional photosynthesis and growth.
B)It attaches to a plasma membrane receptor and results in gene activation to produce the enzyme amylase that releases sugars for additional cell growth,division,and elongation.
C)In the presence of light,it increases the formation of additional DNA that codes for additional plant structures.
D)In the presence of unidirectional light,it moves to the shady side and activates an ATP-driven proton pump that results in weakened cell walls and eventual elongation.
E)In the presence of light,it increases the turgor pressure of the cell and accelerates growth.

Question 29

Long-day plants flower when the day length is longer than the critical period.

Question 30

A hormone that causes cell division and is found in coconut milk and in dividing root tissue is

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

Question 31

Which of the following plant hormones prevents plant tissues from senescing,or aging?

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

Question 32

Which of the following statements is NOT correct about a circadian rhythm?

A)These rhythms tend to persist even in the absence of daily light cues.
B)An example is the opening of stomates in the morning and their closing at night.
C)If plants are maintained in total darkness or total light,their circadian rhythm acts on a faster time scale.
D)The primary usefulness of circadian rhythms seems to be to measure day-length changes so plants respond appropriately to seasonal environmental changes.

Question 33

Which of the following hormones are believed to be involved in abscission?

A)ethylene
B)auxin
C)gibberellin
D)All of the above are correct.

Question 34

Figure: The cylinders in this experiment represent a 24-hour period.The light area represents light periods during a 24-hr.period and the dark area represents dark periods during a 24-hr.period.The critical length of dark vs.light periods for flowering is depicted by the dotted line.Note that some plants are flowering and some are not flowering.Study the results of this experiment on photoperiodism and flowering to determine whether the following statements are True or False.
Short-day plants flower when the day length is shorter than the critical length,but the required dark period is interrupted by a flash of light.

Question 35

Which statement is NOT true about photoperiodism?

A)A short-day plant flowers when the day length is shorter than a critical length.
B)A day-neutral plant flowers according to some form of regulation other than photoperiodism.
C)A long-day plant will flower when the day length is longer than a critical length.
D)The phytochrome form P_fr is converted to P_r in daylight,producing the active form that induces flowering in long-day plants.

Question 36

Photoperiodism requires

A)a biological clock which can measure time.
B)a photoreceptor called phytochrome.
C)increased turgor pressure.
D)protease inhibitors.
E)a biological clock which can measure time and a photoreceptor called phytochrome only are correct.

Question 37

How does auxin actually cause stems to curve towards the light?

A)In the presence of blue light,auxin triggers additional photosynthesis and growth.
B)In the presence of light,auxin increases the turgor pressure of the cell and accelerates growth.
C)In the presence of light,auxin increases the formation of hydrolytic enzymes that release energy needed for growth purposes.
D)In the presence of light,auxin moves toward the light source and activates a protein that binds to DNA and starts enzyme production.
E)In the presence of unidirectional light,auxin moves to the shady side and activates an ATP-driven proton pump that results in weakened cell walls and eventual elongation.

Question 38

Which of the following defense systems would most likely have evolved in response to the leaves of a plant being preyed upon by aphids?

A)After the plant is chewed it produces a proteinase inhibitor that will destroy the digestive enzymes of the predator feeding upon it.The proteinase inhibitor will be produced throughout the entire plant in order to discourage predation in other areas of the plant.
B)After the plant is chewed it produces a proteinase inhibitor that will destroy the digestive enzymes of the predator feeding upon it.The proteinase inhibitor is produced at the site of injury in an attempt to stem the loss of phloem from the site of injury.
C)The leaves of various plants have evolved to resemble the eggs butterflies in an attempt to decrease the number of butterflies that lay eggs on them.
D)The plants produce tannins in the outer leaves in an attempt to discourage predation by insects.
E)All of the choices are correct.

Question 39

Which of the following plant hormones stimulates the ripening of fruit and inhibits plant growth?

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

Question 40

Which of the following is NOT a physiological change related to photoperiodism?

A)seed germination
B)root branching
C)breaking bud dormancy
D)some flowering
E)onset of senescence

Question 41

If a plant is placed on its side,cells on the lower side of the stem will respond to gravity and elongate,making the stem turn so that it continues to grow downward.

Question 42

Went's experiment in 1926 with oat coleoptiles showed that agar that absorbed auxin from the tips would cause a tipless shoot to curve away from the side where he had placed the agar,suggesting that auxin causes cells to elongate.

Question 43

Mutualism is a beneficial relationship between a plant and animal species.It can lead to the death of the plant species if the animal species is removed from the environment.

Question 44

If you are trying to alter the defensive mechanisms of a plant,which component of the signal transduction pathway would be the ideal place to do this?

A)Alter the receptor molecule on the plasma membrane,cytoplasm or nucleus.
B)Block the relay proteins within the cytoplasm that will convert the signal.
C)Change the gene expression or the cellular process that affects the plants growth.
D)All of these would alter the defensive mechanisms of the plant.

Question 45

Long-day plants will never flower if the day length is shorter than the critical period.

Question 46

Which of the following statements best describes how plants use hormones during signal transduction?

A)The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in gene expression will occur causing a change in the physical expression of the plant.
B)The hormone will trigger a series of relay proteins to alter the signal into one that will impact the cellular machinery.Once the signal is changed the hormone will bind to a specific receptor in the plasma membrane.It will then cause a change in gene expression to occur causing a change in the physical expression of the plant.
C)The hormone will bind to a specific receptor in the plasma membrane.It will then trigger a series of relay proteins that alter the signal into one that will impact the cellular machinery.Once the machinery is altered a change in the physical expression will occur causing a change in the actual genes of the plant.
D)None of these describes how plants use hormones during signal transduction.

Question 47

Auxin stimulates leaf release,while ethylene keeps leaves from falling.

Question 48

A hormone is produced in small amounts in a tissue,and it causes a physiological action within that same tissue soon after its production.

Question 49

Which of the following events will occur in response to gravitrophism?

A)Because of the change in the plants position it will have sediments of statoliths (amyloplasts containing starch granules)settle towards the lower side of the stems and roots and come into contact with the cytoskeletal elements.
B)The stems on the shady side of the plant will elongate due to the presence of auxin.
C)The tendril of the plant will coil around any type of substrate that it comes into contact with.
D)The guard cells will swell with water due to an increase in sodium ions which will cause the plant to grow upright.

Question 50

The conclusion drawn from these results is that the length of the dark period,not the light period,controls flowering.

Question 51

In order for hormones like auxin to be used as a chemical signal within a plant it must travel through the xylem to reach the site of activity.

Question 52

Thigmomorphogenesis is a touch response where the whole plant responds to an environmental stimulus.

Question 53

Cyanogenic glycosides are secondary metabolites that are used as medicines for people.

Question 54

In order for signal transduction to work properly in plants the ______________________.

A)correct hormone needs to bind to the appropriate receptor in order to enter the cell
B)relay proteins need to amplify the signal and convert it into one that will alter the cellular machinery
C)gene expression must change to produce the appropriate cellular process
D)All of the above.