Plant Physiology Exam 3

What is reaction wood in an angiosperm?

a. Tension wood on the adaxial surface

b. Compression wood on the abaxial surface

c. Tension wood on the abaxial surface

d. Wood of compression on the adaxial surface

a. Tension wood on the adaxial surface

How do MAP3K, MAP2K, and MAPK signaling cascades act to modify proteins during signal transduction and amplification?

a. Dephosphorylation

b. Phosphorylation

c. Oxidation

d. Methylation

b. Phosphorylation

Which signaling mechanism inhibits enzyme activity by targeting cysteine residues or prevents bond formation in stress responses or programmed development?

a. Nitrosylation

b. S-acylation

c. Prenylation

d. N-myristoylation

a. Nitrosylation

Which developmental processes are regulated by strigolactones?

a. Leaf and flower senescence

b. Fruit ripening

c. Seed germination

d. Root hair growth

e. Seedling growth

f. Secondary growth

g. Mycorrhizae attraction

d. Root hair growth

f. Secondary growth

g. Mycorrhizae attraction

Which developmental processes are regulated by ethylene?

a. Leaf and flower senescence

b. Fruit ripening

c. Seed germination

d. Root hair growth

e. Seedling growth

f. Secondary growth

g. Mycorrhizae attraction

a. Leaf and flower senescence

b. Fruit ripening

c. Seed germination

e. Seedling growth

What is the intermediate step in indole-3-acetic acid (IAA) biosynthesis?

a. Tryptophan

b. YUCCAs (YUCs)

c. Indole-3-pyruvate (IPyA)

d. 2-oxindole-3-acetic acid

c. Indole-3-pyruvate (IPyA)

What is the precursor of most of the cytokinins?

a. Adenine

b. Cytosine

c. Guanine

d. Thymine

a. Adenine

Auxin is capable of regulating auxin levels inside the cell.

a. True

b. False

a. True

the function of the AUXIN1/LIKE AUXIN1 (AUX1/LAX) proteins is to

a. mediate auxin uptake into the cell via co-transport of two protons along with the auxin anion.

b. maintain an acidic pH of up to 5.5, which facilitates simple diffusion.

c. mediate (IAAH) passive diffusion across the plasma membrane down a concentration gradient.

d. inhibit of both ABCB and PIN auxin efflux activity.

a. mediate auxin uptake into the cell via co-transport of two protons along with the auxin anion.

Electrical signals facilitate communication in distal parts of the plant

a. True

b. False

a. True

After ethylene binds to the ethylene receptor, ETR1, on the luminal side of the ER, CTR1 is activated and phosphorylates EIN2.

a. True

b. False

a. True

Within plant cells, signal transduction pathways never function in isolation but operate as part of a complex web of signaling interactions. What are the types of cross-regulation where the pathways intersect? Select all that apply

a. Primary cross-regulation that involves distinct signaling pathways regulating a shared transduction component in a positive or a negative manner

b. Secondary cross-regulation that involves the output of one signaling pathway regulating the abundance or perception of a second signal

c. Tertiary cross-regulation that involves the outputs of two distinct pathways influencing each other

a. Primary cross-regulation that involves distinct signaling pathways regulating a shared transduction component in a positive or a negative manner

b. Secondary cross-regulation that involves the output of one signaling pathway regulating the abundance or perception of a second signal

c. Tertiary cross-regulation that involves the outputs of two distinct pathways influencing each other

Photoreceptors perceive the (select all that apply)

a. light quantity (number of photons).

b. distance to light source.

c. light quality (wavelength).

d. light intensity.

e. duration of exposure.

a. Light quantity

b. distance to light source, c. light quality

d. light intensity

e. duration of exposure

Photoreceptors perceive the total fluence: fluence rate/time of irradiation.

a. True.

b. False

b. False

The active form of phytochrome (Pfr) cannot revert to its inactive form (Pr).

a. True

b. False

b. False

In order to initiate the changes in gene transcription, the photoreceptor must migrate from the cytoplasm to the nucleus in the Pfr form.

a. True

b. False

a. True

How fast do phytochrome-induced responses occur? Select all that apply

a. Biochemical responses can be observed in several weeks.

b. Morphological response may be observed in hours, days, or weeks.

c. Biochemical and morphological changes are observed in the same time frame.

d. Biochemical responses can be observed in minutes.

b. Morphological response may be observed in hours, days, or weeks.

d. Biochemical responses can be observed in minutes.

Which statements about the law of reciprocity are true? Select all that apply

a. The magnitude of the response depends on the product of the fluence rate and the time of irradiation.

b. A short pulse of very bright red light will induce a response just as a very dim red light for a long time.

c. It is true for both VLFRs and LFRs.

d. It is true for all VLFRs, LFRs and HIRs.

a. The magnitude of the response depends on the product of the fluence rate and the time of irradiation.

b. A short pulse of very bright red light will induce a response just as a very dim red light for a long time.

c. It is true for both VLFRs and LFRs.

What are the primary differences between phyA and phyB?

a. phyA mediates responses to far-red light.

b. phyB responses to red or white light.

c. Nuclear import of phyA is activated by either red or far-red light, or low-fluence broad-spectrum light.

d. Nuclear import of phyB is driven by red-light exposure and is reversible by far-red light.

a. phyA mediates responses to far-red light.

b. phyB responses to red or white light.

c. Nuclear import of phyA is activated by either red or far-red light, or low-fluence broad-spectrum light.

d. Nuclear import of phyB is driven by red-light exposure and is reversible by far-red light.

In which process are phyD and phyE involved?

a. Petiole growth

b. Internode elongation

c. Control of flowering time

d. Germination

a. Petiole growth

b. Internode elongation

c. Control of flowering time

Which processes are mediated by blue light? Select all that apply

a. Chloroplast movements

b. Inhibition of seedling hypocotyl elongation

c. Chlorophyll and carotenoid synthesis

d. Enhancement of respiration

e. Solar tracking

f. Stomatal opening

g. End-of-day response

a. Chloroplast movements

b. Inhibition of seedling hypocotyl elongation

c. Chlorophyll and carotenoid synthesis

d. Enhancement of respiration

e. Solar tracking

f. Stomatal opening

Blue-light responses have short lag times between the light signal and the response making them relatively fast compared to other photomorphogenic changes

a. True

b. False

a. True

Immediately after the blue-light stimulus is removed, the blue light receptors return to the inactive state.

a. True

b. False

b. False

Cryptochromes are found in plants, animals, and insects.

a. True

b. False

a. True

The primary site of cryptochrome action is

a. Golgi.

b. ER.

c. nucleus.

d. plasma membrane.

c. nucleus.

Phytochrome and cryptochrome work together to regulate (select all that apply)

a. circadian rhythm regulation.

b. flowering.

c. stem elongation.

d. chloroplast movement.

a. circadian rhythm regulation.

b. flowering.

c. stem elongation.

Phototropins are associated with which of the following processes? (select all that apply)

a. Photomorphogenesis

b. Phototropism

c. Circadian clock

d. UV-B tolerance

e. Chloroplast movement

b. Phototropism

e. Chloroplast movement

What happens to phototropins after blue light perception? (Select all that apply)

a. Autophosphorylation occurs.

b. Kinase domain is activated.

c. PHY domain is activated.

a. Autophosphorylation occurs.

b. Kinase domain is activated.

Responses to UV-B radiation include (select all that apply)

a. gene regulation.

b. the inactive dimer forms two active monomers after perception of UV-B radiation.

c. active monomers enter the nucleus.

d. inactive dimer enters the nucleus.

a. gene regulation.

b. the inactive dimer forms two active monomers after perception of UV-B radiation.

c. active monomers enter the nucleus.

The endosperm is rich in

a. starch.

b. tannins.

c. lipids.

d. proteins.

a. starch.

c. lipids.

d. proteins.

You can distinguish eudicots from monocots by the number of seed leaves in the embryo.

a. True

b. False

a. True

The hormones abscisic acid (ABA) and gibberellin (GA) play an important role in regulating _______ dormancy.

a. endogenous

b. exogenous

c. both endogenous and exogenous

d. neither endogenous nor exogenous

a. endogenous

High ABA and low GA sensitivity is found later in seed development and favors dormancy.

a. True

b. False

a. True

Environmental conditions that break dormancy activate a genetic network that affects the balance between the responses to ABA and GA.

a. True

b. False

a. True

Many seeds need to experience a period of low temperature in order to germinate. This process is referred to as

a. chilling

b. scarification

c. refrigeration

d. stratification

d. stratification

Chemicals such as nitric oxide (NO) and nitrate have the ability to break seed dormancy by employing which of these mechanisms? (Select all that apply)

a. Down-regulating ABA synthesis

b. Down-regulating ABA signalling

c. Up-regulating GA synthesis

d. Up-regulating GA signalling

a. Down-regulating ABA synthesis

b. Down-regulating ABA signalling

c. Up-regulating GA synthesis

d. Up-regulating GA signalling

The major driving force of water uptake during germination is capillary action.

a. True.

b. False

b. False

Radical emergence can occur as a (select all that apply)

a. one-step process where surrounding tissues become physically weakened during imbibition, allowing the radicle to emerge unimpeded.

b. one-step process where the radicle expands sufficiently during imbibition to rupture the surrounding tissues.

c. two-step process during which the surrounding tissues must first undergo metabolic weakening before the radicle can emerge from the seed.

a. one-step process where surrounding tissues become physically weakened during imbibition, allowing the radicle to emerge unimpeded.

b. one-step process where the radicle expands sufficiently during imbibition to rupture the surrounding tissues.

c. two-step process during which the surrounding tissues must first undergo metabolic weakening before the radicle can emerge from the seed.

Starch degradation is initiated by which of the following enzymes in cereals?

a. Only α -amylase

b. Only β-amylase

c. Both α-amylase and β-amylase

d. Neither α-amylase nor β-amylase

c. Both α-amylase and β-amylase

Seed storage proteins contain a greater percentage of nitrogen rich amino acids compared to other proteins.

a. True

b. False

a. True

Cells can expand or grow (Select all that apply)

a. in one direction (tip growth).

b. nondirectionally (diffuse growth).

c. based on the orientation of the microtubules.

d. only in the direction of the sun.

e. based on the orientation of the cellulose microfibrils.

a. in one direction (tip growth).

b. nondirectionally (diffuse growth).

c. based on the orientation of the microtubules.

e. based on the orientation of the cellulose microfibrils.

When seedlings are grown in the dark, they are etiolated. What do these seedlings look like? Select all that apply

a. Long, spindly hypocotyl

b. Closed cotyledons

c. Nonphotosynthetic proplastids resulting in a pale-yellow color in the unexpanded leaves

d. Bright green expanded leaves

a. Long, spindly hypocotyl

b. Closed cotyledons

c. Nonphotosynthetic proplastids resulting in a pale-yellow color in the unexpanded leaves

Which are functions of the root cap? Select all that apply

a. Protection from abiotic stress

b. Secretion of compounds to aid in root penetration

c. Perception of gravity

d. Mobilization of mineral nutrients

a. Protection from abiotic stress

b. Secretion of compounds to aid in root penetration

c. Perception of gravity

d. Mobilization of mineral nutrients

In the presence of ethylene, microtubules reorient, leading to which type of growth?

a. Elongation of cells

b. Lateral expansion of cells

c. Cell expansion equally in all directions

d. Tip growth

b. Lateral expansion of cells

Auxin can play a role in cell expansion by inducing apoplast acidification through the increase of plasma membrane H+- ATPase activity.

a. True

b. False

a. True

Statoliths, which are large and dense amyloplasts, play a major role in the detection of what?

a. Gravity

b. Red and far-red light

c. Blue light

d. Drought stress

a. Gravity

Which is the photoreceptor that mediates the phototropism response?

a. Cryptochromes

b. Phototropins

c. Phytochromes

d. UVR8

b. Phototropins

Where are apical meristems found in plants? Select all that apply

a. The tips of roots

b. The tips of shoots

c. The vascular cambium

d. The stems

a. The tips of roots

b. The tips of shoots

The developmental zones found in the primary root tip are the

a. maturation zone, rib zone, elongation zone, root tip

b. maturation zone, elongation zone, meristematic zone, root cap

c. maturation zone, elongation zone, primordium zone, root cap

d. meristematic zone, elongation zone, cambium zone, root tip

b. maturation zone, elongation zone, meristematic zone, root cap

Auxin acting at the primary root apex of young seedlings

a. is derived exclusively from vascular transport streams originating in the shoot.

b. can be transported from the shoot or synthesized in the quiescent center.

b. can be transported from the shoot or synthesized in the quiescent center.

In shoot apical meristem, where are the rarely dividing clusters of initial cells located?

a. Central zone

b. Rib zone

c. Peripheral zone

d. Meristematic zone

d. Meristematic zone

The plant phyllome includes which of the following (select all that apply)

a. Leaves

b. Bracts

c. Bud scales

d. Floral organs

a. Leaves

b. Bracts

c. Bud scales

d. Floral organs

Which structure is absent on a sessile leaf?

a. Stipule

b. Petiole

c. Rachis

d. Node

b. Petiole

On plants with compound leaves, axillary buds are found at the

a. base of each leaflet.

b. node along the stem.

b. node along the stem.

The petiole is

a. a synonym for the shoot.

b. the leaf stalk that joins the leaf blade.

b. the leaf stalk that joins the leaf blade.

Asymmetric division of meristemoid mother cells produces these two distinct daughter cells.

a. A stomatal lineage ground cell and a meristemoid

b. Another meristemoid mother cell and a guard cell.

a. A stomatal lineage ground cell and a meristemoid

Meristemoids may differentiate into

a. guard mother cells.

b. guard cells.

a. guard mother cells.

The typical venation patterns in angiosperms are called (select all that apply)

a. reticulate.

b. articulate.

c. perpendicular.

d. parallel.

a. reticulate.

d. parallel.

A thin vascular bundle that connects the vascular system of the leaf with the vascular system of the stem is referred to as

a. procambium.

b. sympodium.

c. leaf primordium.

d. leaf trace

d. leaf trace

The formation of vascular tissues is stimulated by

a. auxin.

b. cytokinin.

c. gibbellin.

d. ethylene.

a. auxin.

In the leaf vascular system, small diameter veins primarily function in

a. phloem loading

b. bulk transport of water, metabolites, and minerals

c. bulk transport of sucrose

d. bulk transport of sucrose

a. phloem loading

What is the initial signal for axillary bud outgrowth?

a. Auxin

b. Sucrose

c. Cytokinin

d. Strioglactone

b. Sucrose

Cereal (e.g. maize) root systems (Select all that apply)

a. are the same as dicot root systems.

b. have primary root that develops from the radicle.

c. have lateral roots.

d. have seminal roots (adventitious roots that branch from the hypocotyl of the embryo).

e. have crown roots

f. have brace roots

b. have primary root that develops from the radicle.

c. have lateral roots.

d. have seminal roots (adventitious roots that branch from the hypocotyl of the embryo).

e. have crown roots

f. have brace roots

Phosphorus-deficient plants have (Select all that apply)

a. no changes to root architecture.

b. shallow root systems.

c. many more lateral roots in the upper part of the system.

d. longer, denser root hairs.

e. increased root:shoot ratio.

f. formation of aerenchyma (air spaces in the cortex).

b. shallow root systems.

c. many more lateral roots in the upper part of the system.

d. longer, denser root hairs.

e. increased root:shoot ratio.

f. formation of aerenchyma (air spaces in the cortex).

Which sentence is true about the lateral meristems? Select all that apply

a. The vascular cambium is a lateral meristem.

b. The cork cambium or phellogen is a lateral meristem.

c. The lateral meristem is scattered throughout the cortical tissue.

d. The periderm is a lateral meristem.

a. The vascular cambium is a lateral meristem.

b. The cork cambium or phellogen is a lateral meristem.

Which statement(s) describe(s) bark?

a. Bark is composed of the periderm cells only.

b. Bark is composed of all tissues outside the vascular cambium.

c. Bark originates form two meristems: The phellogen and the vascular cambium.

d. Salicylic acid and quinine are bark-derived medicinal compounds.

b. Bark is composed of all tissues outside the vascular cambium.

c. Bark originates form two meristems: The phellogen and the vascular cambium.

d. Salicylic acid and quinine are bark-derived medicinal compounds.

What is the function of wood? Select all that apply

a. Transport

b. Production of additional xylem

c. Storage

d. Mechanical functions

a. Transport

c. Storage

d. Mechanical functions

Senescence (select all that apply)

a. is only regulated by environmental factors.

b. is the energy-dependent, autolytic (self-digesting) process that leads to the death of targeted cells.

c. is controlled by the interaction of environmental factors with genetically regulated developmental programs.

d. is only regulated by genetic factors.

e. results in cellular structures and macromolecules being broken down and translocated away from the senescing organ (typically leaves) to actively growing regions that serve as nutrient sinks.

b. is the energy-dependent, autolytic (self-digesting) process that leads to the death of targeted cells.

c. is controlled by the interaction of environmental factors with genetically regulated developmental programs.

e. results in cellular structures and macromolecules being broken down and translocated away from the senescing organ (typically leaves) to actively growing regions that serve as nutrient sinks.

What are the types of plant senescence based on the level of structural organization of the senescing unit? Select all that apply

a. Organelle senescence

b. Programmed cell death

c. Organ senescence

d. Whole plant senescence

b. Programmed cell death

c. Organ senescence

d. Whole plant senescence

Which statement(s) about leaf senescence are true?

a. During leaf senescence, nutrients are remobilized from the source leaf to vegetative or reproductive sinks.

b. During leaf senescence, cells undergo programmed cell death.

c. Leaf senescence is only regulated by genetic factors.

d. During leaf senescence, nutrients are remobilized from the sink leaf to vegetative or reproductive sources.

e. Leaf senescence results in cellular structures and macromolecules being broken down and translocated away from the senescing organ (typically leaves) to actively growing regions that serve as nutrient sinks.

a. During leaf senescence, nutrients are remobilized from the source leaf to vegetative or reproductive sinks.

b. During leaf senescence, cells undergo programmed cell death.

c. Leaf senescence is only regulated by genetic factors.

e. Leaf senescence results in cellular structures and macromolecules being broken down and translocated away from the senescing organ (typically leaves) to actively growing regions that serve as nutrient sinks.

Leaf abscission is regulated by (Select all that apply)

a. interaction of auxin and ethylene.

b. formation of the abscission zone.

c. formation of the petiole zone.

d. interaction of auxin and cytokinin.

a. interaction of auxin and ethylene.

b. formation of the abscission zone.

c. formation of the petiole zone.

What are the stages of leaf abscission? Select all that apply

a. Leaf maintenance phase

b Abscission induction phase

c. Abscission phase

d. There are no stages, it happens all at once

a. Leaf maintenance phase

b Abscission induction phase

c. Abscission phase

What are the different life cycles of angiosperms? Select all that apply

a. Annual

b. Semi-annual

c. Biennial

d. Perennial

a. Annual

c. Biennial

d. Perennial

Which statement(s) about monocarpic and polycarpic plants is(are) true? Select all that apply

a. Monocarpic plants are usually perennials.

b. Monocarpic plants reproduce only once.

c. Polycarpic plants reproduce over multiple seasons.

d. Polycarpic plants are usually annuals.

b. Monocarpic plants reproduce only once.

c. Polycarpic plants reproduce over multiple seasons.

What are the stages of leaf abscission? Select all that apply

a. Leaf maintenance phase

b Abscission induction phase

c. Abscission phase

d. No phases, happens all at once

a. Leaf maintenance phase

b Abscission induction phase

c. Abscission phase