Plant Physiology Exam 4

What are the risks of delaying flowering?
a. Herbivory (being eaten)
b. Dying from abiotic stress
c. Being outcompeted by other plants
d. There are no risks of delaying flowering.

a. Herbivory (being eaten)
b. Dying from abiotic stress
c. Being outcompeted by other plants

In most species of the plant kingdom, the factors that appear to lead to flowering are
a. age.
b. polyploidy.
c. size.

a. age.
c. size.

Plants can control the developmental phase timing (vegetative to reproductive) because they produce new organs from the apical meristem.
a. True
b. False

a. True

What are the stages of postembryonic development?
a. Juvenile phase
b. Resting phase
c. Vegetative phase
d. Reproductive phase
e. Stationary phase

a. Juvenile phase
c. Vegetative phase
d. Reproductive phase

Temperature compensation means that a plant’s circadian clock will not keep the same time in different temperatures.
a. True
b. False

b. False.

If a pulse of light is given in the first hours of the subjective night, the expected response is that the organism interprets it as the end of the previous day.
a. True
b. False

a. True

Long day plants (LDP)
a. Flower only in long days (qualitative LDPs)
b. Their flowering is accelerated by long days (quantitative LDPs)
c. Flower only in the winter (qualitative and quantitative LDPs)

a. Flower only in long days (qualitative LDPs)
b. Their flowering is accelerated by long days (quantitative LDPs)

When a night break occurs, an SDP will flower if
a. the duration of darkness is greater than the critical point of day length.
b. both a dark period of sufficient duration and a dawn signal at an appropriate time in the circadian cycle

b. both a dark period of sufficient duration and a dawn signal at an appropriate time in the circadian cycle.

Vernalization
a. Is an irreversible, metabolically active process that causes the plant to flower
b. results in the acquisition of competence of the meristem to undergo the floral transition
c. Is the cold temperature requirement for flowering. The term is derived from the Latin word for “spring.”

b. results in the acquisition of competence of the meristem to undergo the floral transition
c. Is the cold temperature requirement for flowering.

A plant is capable of “devernalizing.”
a. True
b. False

a. True

What is the transmissible flowering stimulus?
a. A protein that is the long-distance signal during flowering
b. The RNA that is the long-distance signal during flowering
c. The molecular complex that initiates the flowering cascade at the meristems
d. The receptor activated by the long-distance signal to start flowering

a. A protein that is the long-distance signal during flowering

The flowering stimulus is different among plants with different photoperiodic requirements.
a. True
b. False

b. False

If an induced leaf from a neutral-day plant is grafted to a long day plant (LDP) stem, the LDP can be induced to flower.
a. True
b. False

a. True

Gibberellins can induce flowering.
a. True
b. False

a. True

How does a homeotic gene act in flowering?
a. Specifies leaf formation
b. Specifies root architecture to support flowering
c. Serves as major developmental switch that activates the entire genetic program to make floral structures
d. Gives floral organs their identity.

c. Serves as major developmental switch that activates the entire genetic program to make floral structures
d. Gives floral organs their identity.
Homeotic genes act as major developmental switches that activate the entire genetic program for a particular structure. The expression of homeotic genes thus gives organs their identity.

Loss of Class B activity results in
a. formation of stamens instead of petals in the second whorl, and of petals instead of stamens in the third whorl.
b. formation of sepals instead of petals in the second whorl, and of carpels instead of stamens in the third whorl.

b. formation of sepals instead of petals in the second whorl, and of carpels instead of stamens in the third whorl.

Class D genes are responsible for pollen formation.
a. True
b. False

b. False

During microsporogenesis
a. new flowers develop.
b. development of the male gametophyte, or pollen grain, begins.
c. cells in the anther divide to form diploid pollen mother cells (microsporocytes) that subsequently undergo meiosis to produce haploid microspores.

b. development of the male gametophyte, or pollen grain, begins.
c. cells in the anther divide to form diploid pollen mother cells (microsporocytes) that subsequently undergo meiosis to produce haploid microspores.

Pollen grains have highly sculpted cell walls to help pollinators transfer the pollen from flower to flower.
a. True
b. False

a. True

How many cells and nuclei does a mature angiosperm embryo sac have?
a. Seven cells and seven nuclei
b. Seven cells and eight nuclei
c. Eight cells and eight nuclei
d. Eight cells and seven nuclei

b. seven cells and eight nuclei

Which of the steps shown occurs last in the process of pollination?
a. Pollen adheres to the papillae cells.
b. Pollen in hydrated.
c. The pollen tube reaches the ovule.
d. The pollen is polarized.
e. Ca²⁺ signals reorganize the cytoskeleton

c. The pollen tube reaches the ovule.

Successful fertilization in angiosperms occurs when
a. pollination is complete.
b. double fertilization occurs.

b. double fertilization occurs.

A seed contains these three basic structural features.
a. Embryo, food storage tissue and seed coat
b. Embryo, seed coat and fruit
c. Embryo, food storage tissue and fruit
d. Embryo, seed coat and fruit

a. Embryo, food storage tissue and seed coat

The pericarp is composed of the seed coat fused to the fruit wall.
a. True
b. False

a. True

What makes Arabidopsis an ideal model for the study of apical-basal polarity determination?
a. The presence of two cotyledons instead of only one.
b. The highly stereotypical cell-divisions pattern in early embryonic development.
c. The capacity of this plant to change apical-basal orientation.
d. The clear apical-basal axis it possesses.

b. The highly stereotypical cell-divisions pattern in early embryonic development.

How are the lineage-dependent mechanisms of development in plants different from that of animals?
a. Lineage-dependent mechanisms in plants are not self-contained.
b. Cell division patterns in plants are less variable, small alterations can affect the ability of forming basic embryonic structures.
c. Cell division patterns in plants are more variable but still form basic embryonic structures.
d. None of the above: Plants do not have lineage-dependent development mechanisms.

c. Cell division patterns in plants are more variable but still form basic embryonic structures.

The origin of the endosperm in flowering plants is from the
a. mother plant only.
b. mitotic divisions of the primary endosperm nucleus resulting from double fertilization
c. father plant only.

b. mitotic divisions of the primary endosperm nucleus resulting from double fertilization

The endosperm is rich in
a. starch.
b. terpenes.
c. lipids
d. proteins

a. starch.
c. lipids
d. proteins

Somatic embryogenesis proceeds in the absence of endosperm development. This embryo is the same size as one formed by double fertilization because it originates from a single somatic cell.
a. True
b. False

b. False

What gives the seed coat its color?
a. Chlorophyll
b. Carotenoids
c. Condensed tannins
d. It varies from plant to plant.

c. Condensed tannins

One of the functions of the seed coat is to regulate dormancy, thereby ensuring that favorable conditions exist before germination.
a. True
b. False

a. True

A recalcitrant seed is a seed
a. with high water content and active metabolism
b. with desiccation tolerance
c. with high water content and inactive metabolism
d. without desiccation tolerance.

a. with high water content and active metabolism
d. without desiccation tolerance.

What are the protective functions of Late-embryogenesis-abundant (LEA) proteins?
a. Ion binding
b. Antioxidant activity
c. Hydration buffering
d. Membrane and protein stabilization
e. Cell division

a. Ion binding
b. Antioxidant activity
c. Hydration buffering
d. Membrane and protein stabilization

The water potential of a mature seed is between 50 and 350 MPa.
a. True
b. False

b. False

Mature seeds have as little as 0.1 g water g–1 dry weight, with water potentials between –350 and –50 MPa.

In dehiscent dry fruit, where is the tension generated to break the extracellular matrix?
a. Septum internal cells
b. Lignified layer and adjacent tissues
c. The cells that secrete the extracellular matrix
d. The midpoint of the valve

b. Lignified layer and adjacent tissues

Phenylpropanoid compounds in fruit have the unfavorable effect of turning the fruit brown.
a. True
b. False

a. True

In a mature climacteric fruit, what happens during fruit ripening?
a. Ethylene production spikes.
b. Respiration increases.
c. Ethylene production is downregulated.
d. Respiration decreases.

a. Ethylene production spikes.
b. Respiration increases.

Non-climacteric fruits require ethylene for ripening.
a. True
b. False

b. False

Adaptation refers to the response of a population to a change in the environment mediated by _______ that alter the expression of genes but not the genetic code.
a. heritable epigenetic changes
b. fixing of a genetic change
c. distribution of seeds to a remote location

a. heritable epigenetic changes
b. fixing of a genetic change

Generally, adaptive mechanism to environmental conditions involves avoidance of the damaging effects of the environmental condition.
a. True
b. False

a. True

Which of the following environmental factors could lead to membrane destabilization?
a. Water deficit
b. Chilling
c. Temperature
d. Salinity

a. Water deficit
b. Chilling
c. Temperature
d. Salinity

Effects of the thinning of the ozone layer include
a. formation of lesions.
b. induction of programmed cell death.
c. ROS production.
d. cellular dehydration.

a. formation of lesions.
b. induction of programmed cell death.
c. ROS production.

What are the components of salinity stress?
a. The “ice cream effect,” where salt forms ice crystal in the xylem
b. Nonspecific osmotic stress that causes water deficits
c. Nonspecific ion effects that mimic mineral nutrients and induce ROS
d. Specific ion effects that cause accumulation of toxic ions

b. Nonspecific osmotic stress that causes water deficits
e. Specific ion effects that cause accumulation of toxic ions

_______ sensing can be used to detect the accumulation of ROS.
a. Biophysical
b. Metabolic
c. Biochemical
d. Epigenetic

b. Metabolic.

Ca²⁺-permeable channels are known to be involved in which processes?
a. Metabolic sensing
b. Heat stress
c. Osmotic stress
d. Biochemical sensing

b. Heat stress
c. Osmotic stress
d. Biochemical sensing

The stress-sensing mechanisms of plants never act in combination to activate a response.
a. True
b. False

b. False

ROS are
a. only produced in response to environmental stress conditions.
b. produced during normal metabolic reactions in cells, such as photosynthesis, respiration, and lipid oxidation.

b. produced during normal metabolic reactions in cells, such as photosynthesis, respiration, and lipid oxidation.

ABA regulates the root–shoot ratio during water stress in conjugation with
a. GA.
b. auxin.
c.alkaloids.
d. amino acids.

b. auxin.

During hypoxia, which hormone induces aerenchyma formation?
a. Jasmonic acid
b. Auxin
c. Abscisic acid
d. Ethylene

d. Ethylene

Which of the following statements about phytochelatins are correct?
a. They contain glutamate.
b. They contain glycine.
c. They chelate toxic metals such as cadmium and arsenic.
d. The chelate ABA.
e. They contain cysteine.

a. They contain glutamate.
b. They contain glycine.
c. They chelate toxic metals such as cadmium and arsenic.
e. They contain cysteine.

After an abiotic stress subsides
a. all plants go through a recovery process, where the stress response mechanisms are inactivated and would have to be reactivated if the stress were encountered again.
b. some plants maintain a readiness to counter the recurrence of stress by keeping certain stress- response regulatory mechanisms active even after the stress subsides.

b. Some plants maintain a readiness to counter the recurrence of stress by keeping certain stress- response regulatory mechanisms active even after the stress subsides.

Ca²⁺-permeable channels are known to be involved which processes?
a. Metabolic sensing
b. Heat stress
c. Osmotic stress
d. Epigenetic sensing

b. Heat stress
c. Osmotic stress