Deck 26: Flowering Plants: Control of Growth Responses

Question 1

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

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

Answer 1

A

Question 2

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

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

Answer 2

B

Question 3

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)auxin

Answer 3

D

Question 4

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 5

Which of the following ions is associated with auxin and used during signal transduction that causes a plant to bend towards a light source?

A)H⁺
B)Ca²⁺
C)Na⁺
D)Mg²⁺

Question 6

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 7

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

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

Question 8

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 9

________ 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 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

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 12

What is the tropism that describes the movement of a plant towards light?

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

Question 13

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 14

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.

Question 15

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

Question 16

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 17

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 18

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 19

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

Question 20

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 21

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 22

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

Question 23

Explain how abscisic acid promotes the closure of stomates.Identify the molecules involved at each step. A.________
B.________
C.________
D.________

Question 24

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

Question 25

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

Question 26

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 27

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

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

Question 28

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 29

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

A)An example is the opening of stomata in the morning and their closing at night.
B)These rhythms tend to persist even in the absence of daily light cues.
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 30

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 31

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 32

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 33

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 34

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 35

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

Question 36

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 37

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 38

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

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

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 41

Explain the mechanisms required for a Venus flytrap to close its trap when stimulated by an insect.

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

Explain how the stems and roots of a plant will respond at the cellular level if it is placed upon its side.

Question 44

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

A)Because of the change in the plant's 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 45

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 46

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 answer choices are correct.

Question 47

Describe how phytochrome is used to determine plant spacing.

Question 48

Explain how a hormone will trigger the signal transduction pathway in a plant.

Question 49

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

Question 50

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 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

The Pr → Pfr conversion cycle is known to control various growth functions in plants.Which of the following functions does the cycle NOT control?

A)decrease water transport
B)promote seed germination
C)inhibit shoot elongation
D)promote flowering
E)affect accumulation of chlorophyll in plant tissue