plant bio final chapters 27/30
All of the following can induce embolisms in a vessel or tracheid EXCEPT: a. an air bubble coming in contact with a torus blocking an aperture of a bordered pit-pair. b. air being sucked in through a pit-membrane pore. c. an insect bite that damages xylem tissue. d. freezing of the xylem sap. e. drought.
A
Folke Skoog and his colleagues found that ______ stimulated cells of tobacco to divide in culture. a. coconut milk b. a sugar c. a salt d. a vitamin e. auxin
A
In Arabidopsis, the ethylene receptor is located in the: a. endoplasmic reticulum. b. plasma membrane. c. Golgi apparatus. d. chloroplast. e. nucleus.
A
In apical dominance, the apical bud: a. inhibits the growth of lateral buds. b. stimulates the growth of lateral buds. c. stimulates the upward growth of the stem. d. stimulates the growth of leaves. e. inhibits the downward growth of the root.
A
In roots of Arabidopsis, cytokinin ______ the initiation of lateral roots by preventing the establishment of a(n) ______ gradient. a. inhibits; auxin b. inhibits; gibberellin c. stimulates; auxin d. stimulates; gibberellin e. stimulates; ethylene
A
In the ABA-induced closing of stomata, the following ion fluxes occur across guard cell plasma membranes: first calcium ions flow ______, then anions flow ______, and finally potassium ions flow ______. a. in; out; out b. in; in; in c. out; in; out d. out; out; in e. out; out; out
A
In vascular plants, cavitation is the: a. rupture of water columns. b. expulsion of air from water columns. c. formation of air bubbles due to particulate matter. d. reduction of surface tension at the meniscus spanning pores in the pit membrane. e. filling of vessels with water vapor.
A
Plants in hot climates regularly close their stomata at midday because ______ accumulates in the leaf, and the leaves become _______. a. carbon dioxide; dehydrated b. carbon dioxide; turgid c. oxygen; dehydrated d. oxygen; turgid e. oxygen; depleted of carbon dioxide
A
Stomatal transpiration involves two steps: a. evaporation and diffusion. b. evaporation and active transport. c. osmosis and evaporation. d. osmosis and active transport. e. photosynthesis and respiration.
A
The most widespread and active brassinosteroid is: a. brassinolide. b. 24-epibrassinolide. c. S-adenosylmethionine. d. strigolactone. e. castasterone.
A
Water moving from the cytosol of a cortical cell directly into the cytosol of an adjacent cortical cell via plasmodesmata follows the: a. symplastic pathway only. b. apoplastic pathway only. c. transcellular pathway only. d. symplastic and apoplastic pathways. e. apoplastic and transcellular pathways.
A
Which of the following is NOT a benefit of hydraulic redistribution? a. It prevents the dry-season transpiration of Amazonian trees. b. It reduces the possibility of water logging in surface soils. c. It allows mycorrhizae to persist in dry soils. d. It transfers water from the wet soil surface to deep soil layers that are dry. e. It makes water available to neighboring plants that are less deeply rooted.
A
Which of the following is NOT evidence supporting the role of phloem in sugar transport? a. Honeydew contains amino acids but not sucrose. b. 14C-labeled sucrose is transported in sieve tubes. c. The exudate from the stylets of feeding aphids is mainly sucrose. d. Radioactive assimilates are transported in the phloem. e. When a tree is girdled, the bark above the ring becomes swollen.
A
Which of the following statements concerning the role of auxin in developing leaves of Arabidopsis is FALSE? a. Auxin is produced first at the leaf base and later at the tip. b. Auxin stimulates the differentiation of vascular tissue. c. Auxin induces the formation of lateral veins. d. Auxin is produced by cells that will differentiate into hydathodes. e. Auxin induces the formation of the midvein.
A
______ activates the biosynthesis of ________, which then activates the genes that encode protease inhibitors. a. Systemin; jasmonic acid b. Jasmonic acid; auxin c. Brassinosteroid; systemin d. Salicylic acid; jasmonic acid e. Systemin brassinosteroids
A
A PIN protein: a. is an auxin influx carrier. b. is an auxin efflux carrier. c. catalyzes the conversion of auxin to tryptophan. d. catalyzes the conversion of auxin to indole. e. is a synthetic auxin.
B
Cell wall extensibility, and thus cell expansion, is increased by ______ but decreased by ______. a. auxin and ethylene; GA and ABA b. auxin and GA; ABA and ethylene c. auxin and ABA; GA and ethylene d. ABA and ethylene; auxin and GA e. ABA and GA; auxin and ethylene
B
If a coleoptile tip is covered with a blackened glass tube then illuminated from the side, the coleoptile will: a. die. b. not bend. c. bend toward the light. d. bend away from the light. e. bend at right angles to the light.
B
In germinating barley seeds, the ______ releases gibberellins, which then diffuse to the ______ where they stimulate the synthesis of hydrolytic enzymes. a. endosperm; aleurone layer b. embryo; aleurone layer c. aleurone layer; embryo d. aleurone layer; endosperm e. embryo; seed coat
B
In the ethylene signaling pathway in Arabidopsis, when ethylene is absent, then ____ is active. a. EIN2 b. CTR1 c. EIN3 d. ERF1 e. Cu
B
Mycorrhizae are especially important in the plant's absorption of: a. zinc. b. phosphorus. c. manganese. d. copper. e. iron.
B
Phototropins are: a. osmoticums. b. photoreceptors. c. microfibrils. d. enzymes. e. active-transport proteins.
B
Sucrose is translocated through sieve tubes: a. via active transport. b. passively. c. via facilitated diffusion. d. via a proton-pumping mechanism. e. via a combination of exocytosis and endocytosis.
B
The brassinosteroid receptor differs from the receptors for auxin, gibberellin, ethylene and cytokinins in that the brassinosteroid receptor: a. is located entirely in the endoplasmic reticulum. b. has an extracellular region, a transmembrane region, and a cytoplasmic region. c. is located entirely in the cytoplasm. d. does not initiate a signaling cascade. e. binds directly with genes in the nucleus.
B
The principle solute involved in creating a water potential gradient in guard cells is: a. H+. b. K+. c. glucose. d. malate. e. Cl- .
B
Transpiration is the: a. flow of water through the xylem. b. loss of water vapor from plants. c. absorption of water by roots. d. loss of carbon dioxide from leaves. e. entry of carbon dioxide into leaves.
B
When tobacco pith callus is treated with higher concentrations of auxin than kinetin, ______ is(are) formed. a. more callus b. roots c. buds d. leaves e. vascular tissue
B
Which of the following statements about ethylene is FALSE? a. The final step in its synthesis in plants is catalyzed by enzymes on the tonoplast. b. Its synthesis in plants begins with the amino acid tryptophan. c. It exerts an influence on many aspects of plant growth and development. d. It is the active component of illuminating gas that affects plant development. e. It has the formula H2C=CH2.
B
Which of the following statements about fruit development is FALSE? a. A parthenocarpic fruit lacks seeds. b. A parthenocarpic fruit lacks ovules. c. Applications of auxin can stimulate carpels to develop into a fruit. d. Removal of seeds from a developing fruit results in reduced fruit growth. e. Application of auxin to a deseeded receptacle stimulates fruit growth.
B
Which of the following statements about sources and sinks in assimilate movement is FALSE? a. A plant part unable to meet its nutritional needs functions as a sink. b. In seedlings, the cotyledons commonly act as the major sinks. c. In mature plants, the upper leaves commonly act as sources for the shoot apex. d. In mature plants, the lower leaves commonly act as sources for the roots. e. Developing fruits are highly competitive sinks.
B
An ion moving across the root via the symplastic pathway would NOT pass across the: a. plasma membrane of the epidermis. b. epidermal cell protoplast. c. cell walls of the exodermis. d. plasmodesmata in the epidermal-cortical cell walls. e. endodermis.
C
As a consequence of girdling a tree: a. its leaves stop exporting solutes. b. its leaves stop importing solutes. c. the bark above the girdle swells. d. the bark above the girdle dies. e. the bark begins to act as a source.
C
Gibberellins promote a ______ orientation of the microtubules underlying the plasma membrane, and ethylene promotes a ______ orientation. a. random; longitudinal b. transverse; random c. transverse; longitudinal d. longitudinal; transverse e. longitudinal; random
C
If wounding causes the destruction of vascular tissues in an herbaceous eudicot stem: a. replacement vascular tissues will not form under any conditions. b. replacement vascular tissues will form if IAA is added to the stem just below the wound. c. replacement vascular tissues will form if the leaves and buds above the wound are intact. d. water will be transported in pith cells instead of in xylem. e. food will be transported in pith cells instead of in phloem.
C
In etiolated pea seedlings, ethylene causes ______ longitudinal growth, ______ radial expansion of epicotyls, and ______ growth of epicotyls. a. increased; increased; horizontal b. increased; decreased; horizontal c. decreased; increased; horizontal d. decreased; increased; angular e. increased; decreased; angular
C
In isolated barley aleurone cells, treatment with GA causes the levels of α-amylase to ______, and treatment with ABA causes the levels to ______. a. increase; remain unchanged b. decrease; remain unchanged c. increase; decrease d. decrease; increase e. increase; increase
C
In stems, polar auxin transport occurs mainly in the: a. vessels only. b. sieve tubes only. c. vascular parenchyma cells only. d. vessels and sieve tubes. e. vessels and parenchyma cells
C
In the ethylene signaling pathway in Arabidopsis, when the EIN2 protein is activated which of the following happens next? a. ETR1 undergoes a conformational change. b. CTR1 is activated. c. the ethylene signal is transmitted into the nucleus. d. a transcription factor is activated. e. genes are activated.
C
The rate of water evaporation doubles for every _____ degree C rise in temperature. a. 2 b. 5 c. 10 d. 15 e. 20
C
When water moving through the cortex via the apoplastic pathway reaches the endodermis: a. it continues through the apoplast. b. it enters the cell walls. c. apoplastic movement is stopped by the Casparian strips. d. the symplastic pathway is blocked. e. the transcellular pathway is blocked.
C
Which of the following statements about apoplastic phloem loading is FALSE? a. It is driven by a proton gradient. b. It occurs via sucrose-proton symport. c. Apoplastic loaders have numerous plasmodesmatal connections. d. In some cases, active transport occurs across the plasma membrane of the sieve tube. e. In some cases, active transport occurs across the plasma membrane of the companion cell.
C
Which of the following statements about cytokinins is FALSE? a. They stimulate cell division. b. They are present in bleeding sap. c. Kinetin is a naturally occurring cytokinin. d. They are found primarily in actively dividing tissues and in root tips. e. The most active naturally occurring cytokinin is zeatin.
C
Which of the following statements about gibberellins is FALSE? a. They induce bolting in long-day plants. b. They induce early flowering in biennials. c. They cause rosette formation in cabbages and carrots. d. They cause development of parthenocarpic apples and currants. e. They are used in the commercial production of seedless grapes
C
Which of the following statements concerning nocturnal transpiration is FALSE? a. For some species it constitutes a significant fraction of the daily water use. b. It may enhance nutrient uptake. c. It occurs when evaporation rates are higher than in the day. d. It is due to stomata not closing completely in the dark. e. It is found in many trees and shrubs.
C
Which of the following statements concerning strigolactone is FALSE? a. It is a terpenoid derived from carotenoids. b. It stimulates bud growth. c. It is present in root exudates. d. It promotes the formation of mycorrhizae. e. It stimulates seed germination of root-parasitic plants.
C
Which of the following statements concerning the uptake of K+ by guard cells is FALSE? a. Uptake of K+ is driven by a proton gradient. b. Uptake of K+ is mediated by a red-light activated ATPase. c. Uptake of K+ is accompanied by the uptake of Cl- . d. Uptake of K+ is accompanied by the accumulation of malate. e. Uptake of K+ creates the necessary water potential gradient.
C
______ is very similar to the amino acid tryptophan. a. Gibberellin b. Cytokinin c. Indoleacetic acid d. Abscisic acid e. Ethylene
C
_________ have recently been ranked along with the "classic five" as a major class of plant hormone. a. Systemins b. Florigens c. Brassinosteroids d. Salicylic acids e. Jasmonates
C
A plant loses the greatest amount of water through the: a. leaf cuticle. b. stem cuticle. c. root cuticle. d. stomata. e. lenticels.
D
An air bubble in a vessel can be prevented from spreading to an adjacent vessel by: a. air seeding. b. transport upward in the transpiration stream. c. movement of a torus away from an aperture of a bordered pit-pair. d. the surface tension of the meniscus spanning the pores of the bordered pit-pair membrane. e. the filtering effect of the roots.
D
Cytokinins are synthesized in ____ and transported from there to all other parts of the plant. a. stems b. shoot apical meristems c. leaves d. roots e. fruits
D
In roots, active transport of minerals is required for: a. uptake by epidermal cells only. b. secretion into the vessels only. c. transport through the apoplast and the symplast only. d. uptake by epidermal cells and secretion into the vessels only. e. uptake by epidermal cells, transport through the symplast, and secretion into the vessels.
D
In studies of leaf senescence, when an excised leaf containing radioactive amino acids is spotted with a kinetin-containing solution, the spot: a. turns yellow and becomes nonradioactive. b. turns yellow and becomes more radioactive. c. remains green and becomes nonradioactive. d. remains green and becomes more radioactive. e. turns brown and becomes nonradioactive.
D
In the acid-growth hypothesis of cell wall extensibility, which of the following events occurs FIRST? a. Expansins disrupt hydrogen bonds. b. Protons are pumped into the cell wall. c. Specific genes are activated. d. A proton-pumping enzyme is activated. e. Cross-links between noncellulosic polysaccharides are broken.
D
In the process of stomatal closing, which of the following events occurs first? a. Water moves out of guard cells. b. Water moves into guard cells. c. Guard cell turgor pressure decreases. d. Guard cell solute concentration declines. e. Guard cell water potential increases.
D
In the process of stomatal opening, the ________ walls of the guard cells ________ relative to their common walls. a. inner; move inward b. inner; move outward c. outer; move inward d. outer; move outward e. outer; remain unchanged
D
Plants with crassulacean acid metabolism: a. open their stomata when conditions are favorable to transpiration. b. convert CO2 to organic acids during the day. c. convert organic acids to CO2 during the night. d. are exemplified by members of the stonecrop family. e. have a pathway for carbon flow much different from that of C4 plants.
D
Radial micellation refers to the ______ of guard cells. a. shape b. opening and closing c. orientation of proteins in the plasma membrane d. orientation of cellulose microfibrils in the cell walls e. mode of attachment between the ends
D
The climacteric is the phase in which fruits undergo a(n): a. decrease in photosynthesis. b. decrease in respiration. c. increase in photosynthesis. d. increase in respiration. e. increase in pectin synthesis.
D
The driving force for assimilate transport is: a. diffusion. b. active transport. c. transpiration. d. osmosis. e. pressure-flow.
D
When transpiration is proceeding at a high rate: a. stomata usually close. b. guttation is at its greatest. c. root pressure can push water to the top of a tall tree. d. water is pulled into the roots by bulk flow. e. hydraulic lift forces water into roots.
D
Which of the following indicates the correct sequence of tissues through which water moves from the soil into the root? a. Root hairs, endodermis, exodermis, cortical cells, vascular cylinder b. Root hairs, endodermis, cortical cells, vascular cylinder, exodermis c. Exodermis, endodermis, epidermis, vascular cylinder, cortical cells d. Epidermis, exodermis, cortical cells, endodermis, vascular cylinder e. Epidermis, endodermis, exodermis, cortical cells, vascular cylinder
D
Which of the following is a phenolic compound with a structure similar to aspirin? a. systemin b. florigen c. brassinosteroids d. salicylic acids e. jasmonic acid
D
Which of the following statements about abscisic acid is FALSE? a. It has no direct role in abscission. b. It induces the closing of stomata. c. It prevents premature seed germination. d. It inhibits the production of seed storage proteins. e. It is produced during water stress.
D
Which of the following statements about second messengers is FALSE? a. They amplify the signal produced by a hormone. b. They contribute to the diversity of responses to a hormone. c. They transfer information from the hormone-receptor complex to the target protein. d. An example is protein kinase. e. An example is calcium ion.
D
Which of the following statements concerning the polymer trapping mechanism is FALSE? a. It is a type of symplastic loading. b. The companion cells are intermediary cells. c. Sucrose is used to synthesize polymers. d. Raffinose and stachyose are actively transported into the sieve tubes. e. Energy is used to create a concentration difference between the mesophyll and the phloem.
D
A dry breeze increases the rate of transpiration mainly because it: a. cools the leaf. b. warms the leaf. c. increases the CO2 gradient across the leaf surface. d. decreases the CO2 gradient across the leaf surface. e. increases the vapor pressure difference across the leaf surface.
E
A pressure chamber can be used to test the cohesion-tension theory by: a. measuring the tensile strength of water. b. following the movement of colored water in the xylem. c. measuring the shrinkage of a trunk caused by negative xylem pressure. d. detecting the rate at which heated water moves through a plant. e. determining the magnitude of the tension in a twig
E
All plant hormones: a. are equally effective in free and bound forms. b. act in the tissues where they are produced. c. are stimulatory. d. are active in large quantities. e. communicate information.
E
Dwarf mutant plants are short because they: a. synthesize too much gibberellin. b. synthesize too much abscisic acid. c. cannot synthesize ethylene. d. cannot synthesize auxin. e. cannot synthesize gibberellin.
E
If cell wall microfibrils are oriented transversely, the cell normally expands: a. in all directions. b. at an oblique angle. c. first laterally and then longitudinally. d. laterally. e. longitudinally
E
In guard cells, _____ is the dominant osmoticum in the morning, and ______ is the dominant osmoticum in the afternoon. a. Cl- ; sucrose b. malate; K+ c. K+, malate d. sucrose; K+ e. K+; sucrose
E
In the process of guttation, all of the following events occur EXCEPT: a. dew-like drops of water form at the tips of grass. b. dew-like drops of water form at the tips of leaves. c. water exudes through stomata that lack the ability to open and close. d. water exudes through openings in structures called hydathodes. e. water forms from the condensation of water from the air.
E
In vascular plants, hydraulic redistribution is the: a. movement of water from roots to leaves. b. flow of water against a water potential gradient. c. movement of water across the endodermis. d. transfer of water across Casparian strips. e. transfer of water by roots from moist to dry regions of the soil.
E
Polar transport is ______ in stems, _______in leaves, and ______ in roots. a. acropetal; acropetal; acropetal b. basipetal; basipetal; basipetal c. acropetal; acropetal; basipetal d. basipetal; acropetal; acropetal e. basipetal; basipetal; acropetal
E
The major difference between the symplastic and the transcellular pathways of the root is that the transcellular pathway involves: a. plasmodesmata. b. protoplasts. c. plasma membranes. d. cell walls. e. vacuoles.
E
The rate of transpiration is affected by stomatal movements and: a. air currents only. b. humidity only. c. temperature only. d. temperature and air currents only. e. temperature, humidity, and air currents.
E
The receptors for both auxin and gibberellin are located in the: a. endoplasmic reticulum. b. plasma membrane. c. Golgi apparatus. d. chloroplast. e. nucleus.
E
Transport of inorganic ions within the leaf occurs via the: a. apoplastic pathway only. b. symplastic pathway only. c. transpiration stream only. d. apoplastic and symplastic pathways only. e. transpiration stream and the apoplastic and symplastic pathways.
E
Which of the following does NOT provide evidence supporting the cohesion-tension theory? a. Water has sufficient tensile strength. b. The water potential in a stem is sufficient. c. In the morning, heated water begins to flow close to the leaves. d. In the morning, the diameter of a tree decreases first in the upper trunk. e. In the evening, the diameter of a tree increases first in the lower trunk.
E
Which of the following is/are present in the highest concentration in sieve-tube sap? a. glucose b. amino acids c. magnesium d. sorbitol e. sucrose
E
Which of the following statements about 2,4-D is FALSE? a. It is a synthetic auxin. b. It is used as an herbicide. c. It is not broken down in plants as readily as IAA. d. It is absorbed more readily than IAA e. It kills grasses more readily than broad-leaf weeds.
E
Which of the following statements about phloem unloading and transport is FALSE? a. Unloading can be apoplastic. b. Unloading can be symplastic. c. In young leaves and roots, unloading is probably passive. d. In storage organs, energy is needed to accumulate sugars in sink cells. e. In young leaves and roots, post-sieve-tube transport is passive.
E
Which of the following statements about stomatal movements is FALSE? a. An increase in CO2 levels usually causes stomata to close. b. Sensors for carbon dioxide are located in guard cells. c. Stomatal opening and closing exhibit circadian rhythms. d. Cacti and pineapple open their stomata at night. e. Temperatures above 30°-35°F usually stimulate stomatal opening.
E
Which of the following statements about xylem and phloem is FALSE? a. They are closely associated spatially. b. They are closely associated functionally. c. They form a continuous vascular system. d. They are involved in long-distance transport. e. Xylem transports only water, and phloem transports only nutrients.
E
Which of the following statements concerning endogenous brassinosteroids is FALSE? a. They are found in virtually every part of the plant. b. They are synthesized from castasterone. c. They are essential for tracheary element differentiation. d. They are required for normal plant growth. e. They are transported from root to shoot in the xylem.
E
Which of the following statements is NOT consistent with the cohesion-tension theory? a. A gradient of water potential exists between the stem and the root. b. Transpiration brings about a lowered water potential in the leaves. c. Water in the xylem is under tension. d. A gradient of water potential provides the driving force for the movement of water from the soil through the plant to the atmosphere. e. Root pressure is essential to the movement of water from roots to leaves.
E