Ch 35-36

Choose the option that best describes the relationship between the cell wall thickness of parenchyma cells versus sclerenchyma cells. Select one: a. The cell walls of parenchyma cells are thinner than those of sclerenchyma cells. b. The cell walls of parenchyma cells are thicker than those of schlerenchyma cells. c. The cell walls of both types of cells are roughly equal. d. The thickness of the cell walls for both types of cells is too variable for a comparison to be made.

Which structure is incorrectly paired with its tissue system? Select one: a. root hair dermal tissue b. palisade parenchyma ground tissue c. guard cell dermal tissue d. companion cell ground tissue e. tracheid vascular tissue

Which of the following is derived from the ground tissue system? Select one: a. root hair b. cuticle c. periderm d. pith e. phloem

Which part of a plant absorbs most of the water and minerals taken up from the soil? Select one: a. taproots b. root hairs c. the thick parts of the roots near the base of the stem d. storage roots e. sections of the root that have secondary xylem

Land plants are composed of all of the following tissue types except Select one: a. mesodermal. b. epidermal. c. meristematic. d. vascular. e. ground tissue.

Vascular plant tissue includes all of the following cell types except Select one: a. vessel elements. b. sieve cells. c. tracheids. d. companion cells. e. cambium cells.

When you eat Brussels sprouts, what are you eating? Select one: a. immature flowers b. large axillary buds c. petioles d. storage leaves e. storage roots

_______ is to xylem as ________ is to phloem. Select one: a. Sclerenchyma cell; collenchyma cell b. Apical meristem; vascular cambium c. Vessel element; sieve-tube member d. Cortex; pith e. Vascular cambium; cork cambium

CO 2 enters the inner spaces of the leaf through the Select one: a. cuticle. b. epidermal trichomes. c. stoma. d. phloem. e. walls of guard cells.

Which of the following cells transport sugars over long distances? Select one: a. parenchyma cells b. collenchyma cells c. sclerenchyma cells d. tracheids and vessel elements e. sieve-tube elements

Which of the following have unevenly thickened primary walls that support young, growing parts of the plant? Select one: a. parenchyma cells b. collenchyma cells c. sclerenchyma cells d. tracheids and vessel elements e. sieve-tube elements

Which of the following are most responsible for supporting mature, nongrowing parts of the plant? Select one: a. parenchyma cells b. collenchyma cells c. trichomes d. tracheids and vessel elements e. sieve-tube elements

The vascular bundle in the shape of a single central cylinder in a root is called the Select one: a. cortex. b. stele. c. endodermis. d. periderm. e. pith.

One important difference between the anatomy of roots and the anatomy of leaves is that Select one: a. only leaves have phloem and only roots have xylem. b. root cells have cell walls and leaf cells do not. c. a waxy cuticle covers leaves but is absent from roots. d. vascular tissue is found in roots but is absent from leaves. e. leaves have epidermal tissue but roots do not.

A student examining leaf cross sections under a microscope finds many loosely packed cells with relatively thin cell walls. The cells have numerous chloroplasts. What type of cells are they? Select one: a. parenchyma b. xylem c. endodermis d. collenchyma e. sclerenchyma

Compared to most animals, the growth of most plants is best described as Select one: a. perennial. b. weedy. c. indeterminate. d. derivative. e. primary.

A vessel element would likely lose its protoplast in which section of a root? Select one: a. zone of cell division b. zone of elongation c. zone of maturation d. root cap e. apical meristem

Gas exchange, which is necessary for photosynthesis, can occur most easily in which leaf tissue? Select one: a. epidermis b. palisade mesophyll c. spongy mesophyll d. vascular tissue e. bundle sheath

Which of the following best describes advantages conferred by compound leaves versus simple leaves? Select one: a. There's a greater chance of capturing photons in intermittently shady areas. b. There is less chance of damage in high-wind areas. c. There's a reduced chance of herbivory. d. There is less surface area for water loss. e. There's a greater chance of capturing photons in intermittently shady areas and less chance of damage in high-wind areas.

Water is most likely to enter a mesophyll cell Select one: a. as a gas. b. as a liquid. c. covalently bound to sugars. d. coupled to ion transport. e. via endocytosis.

Plants contain meristems whose major function is to Select one: a. attract pollinators. b. absorb ions. c. photosynthesize. d. produce more cells. e. produce flowers.

A cell that is most likely to retain the ability to divide, perform metabolic functions, and store photosynthate would be a Select one: a. parenchyma cell in a leaf. b. vessel element in the vascular system. c. endodermal cell in a root. d. bark cell. e. fiber cell.

Which of the following cell types is least likely to be capable of cell division? Select one: a. mesophyll cell in a developing leaf b. parenchyma cell 2 mm from the tip of a root c. parenchyma cell in a dormant axillary bud d. functional tracheid cell in a stem

The driving force that pushes the root tip through the soil is primarily Select one: a. continuous cell division in the root cap at the tip of the root. b. continuous cell division just behind the root cap in the center of the apical meristem. c. elongation of cells behind the root apical meristem. d. the elongation of root hairs. e. continuous cell division of root cap cells.

Shoot elongation in a growing bud is due primarily to Select one: a. cell division at the shoot apical meristem. b. cell elongation directly below the shoot apical meristem. c. cell division localized in each internode. d. cell elongation localized in each internode. e. cell division at the shoot apical meristem and cell elongation directly below the shoot apical meristem.

Axillary buds Select one: a. are initiated by the cork cambium. b. have dormant meristematic cells. c. are composed of a series of internodes lacking nodes. d. grow immediately into shoot branches. e. do not form a vascular connection with the primary shoot.

The following question is based on parts of a growing primary root. Which of the following is the correct sequence from the growing tips of the root upward? Select one: a. I, II, V, III, IV b. III, V, I, II, IV c. II, IV, I, V, III d. IV, II, III, I, V e. I, V, III, II, IV

Which of the following is incorrectly paired with its structure and function? Select one: a. sclerenchyma supporting cells with thick secondary walls b. periderm protective coat of woody stems and roots c. pericycle waterproof ring of cells surrounding the central stele in roots d. mesophyll parenchyma cells functioning in photosynthesis in leaves e. ground meristem primary meristem that produces the ground tissue system

Which of the following root tissues gives rise to lateral roots? Select one: a. endodermis b. phloem c. cortex d. epidermis e. pericycle

A leaf primordium is initiated as a small mound of tissue on the flank of a dome-shaped shoot apical meristem. The earliest physical evidence of the site of a newly forming leaf primordium would be Select one: a. development of chloroplasts in a surface cell of the shoot apical meristem. b. cell division in the shoot apical meristem with the newly forming walls perpendicular to the surface of the meristem. c. preprophase bands parallel to the surface of the meristem in subsurface cells of the shoot apical meristem. d. elongation of epidermal cells perpendicular to the surface of the shoot apical meristem. e. formation of stomata in the epidermal layer of the shoot apical meristem.

Pores on the leaf surface that function in gas exchange are called Select one: a. hairs. b. xylem cells. c. phloem cells. d. stomata. e. sclereids.

Which of the following is a true statement about growth in plants? Select one: a. Only primary growth is localized at meristems. b. Some plants lack secondary growth. c. Only stems have secondary growth. d. Only secondary growth produces reproductive structures. e. Monocots have only primary growth, and eudicots have only secondary growth.

All of the following cell types are correctly matched with their functions except Select one: a. mesophyll-photosynthesis. b. guard cell-regulation of transpiration. c. sieve-tube member-translocation. d. vessel element-water transport. e. companion cell-formation of secondary xylem and phloem.

What would be a plant adaptation that increases exposure of a plant to light in a dense forest? Select one: a. closing of the stomata b. lateral buds c. apical dominance d. absence of petioles e. intercalary meristems

A person working with plants may reduce the inhibition of apical dominance by auxin via which of the following? Select one: a. pruning shoot tips b. deep watering of the roots c. fertilizing d. treating the plants with auxins e. feeding the plants nutrients

What effect does "pinching back" have on a houseplant? Select one: a. increases apical dominance b. inhibits the growth of lateral buds c. produces a plant that will grow taller d. stimulates lateral buds to grow e. increases the flow of auxin down the shoot

Which of the following cells or tissues arise from lateral meristem activity? Select one: a. secondary xylem b. leaves c. trichomes d. tubers e. cortex

A plant has the following characteristics: a taproot system, several growth rings evident in a cross section of the stem, and a layer of bark around the outside. Which of the following best describes the plant? Select one: a. herbaceous eudicot b. woody eudicot c. woody monocot d. herbaceous monocot e. woody annual

Cells produced by lateral meristems are known as Select one: a. dermal and ground tissue. b. lateral tissues. c. pith. d. secondary tissues. e. shoots and roots

Which of the following is a true statement? Select one: a. Flowers may have secondary growth. b. Secondary growth is a common feature of eudicot leaves. c. Secondary growth is produced by both the vascular cambium and the cork cambium. d. Primary growth and secondary growth alternate in the life cycle of a plant. e. Plants with secondary growth are typically the smallest ones in an ecosystem.

What tissue makes up most of the wood of a tree? Select one: a. primary xylem b. secondary xylem c. secondary phloem d. mesophyll cells e. vascular cambium

If you were able to walk into an opening cut into the center of a large redwood tree, when you exit from the middle of the trunk (stem) outward, you would cross, in order, Select one: a. the annual rings, new xylem, vascular cambium, phloem, and bark. b. the secondary xylem, cork cambium, phloem, and periderm. c. the vascular cambium, oldest xylem, and newest xylem. d. the secondary xylem, secondary phloem, and vascular cambium. e. the summer wood, bark, and phloem.

Additional vascular tissue produced as secondary growth in a root originates from which cells? Select one: a. vascular cambium b. apical meristem c. endodermis d. phloem e. xylem

A mutation allows only A gene activity in a developing flower. Which flower part(s) will develop in this plant? Select one: a. sepals b. petals c. stamens d. carpels e. both sepals and petals

While studying the plant Arabidopsis, a botanist finds that an RNA probe produces colored spots in the sepals of the plant. From this information, what can be inferred? Select one: a. The differently colored plants will attract different pollinating insects. b. The RNA probe is transported only to certain tissues. c. The colored regions were caused by mutations that occurred in the sepals. d. The RNA probe is specific to a gene active in sepals. e. More research needs to be done on the sepals of Arabidopsis.

Before differentiation can begin during the processes of plant cell and tissue culture, parenchyma cells from the source tissue must Select one: a. differentiate into procambium. b. undergo dedifferentiation. c. increase the number of chromosomes in their nuclei. d. enzymatically digest their primary cell walls. e. establish a new polarity in their cytoplasm.

the polarity of a plant is established when Select one: a. the zygote divides. b. cotyledons form at the shoot end of the embryo. c. the shoot-root axis is established in the embryo. d. the primary root breaks through the seed coat. e. the shoot first breaks through the soil into the light as the seed germinates.

Totipotency is a term used to describe a cell's ability to give rise to a complete new organism. In plants, this means that Select one: a. plant development is not under genetic control. b. the cells of shoots and the cells of roots have different genes. c. cell differentiation depends largely on the control of gene expression. d. a cell's environment has no effect on its differentiation. e. sexual reproduction is not necessary in plants.

Which of the following statements is false? Select one: a. A preprophase band determines where a cell plate will form in a dividing cell. b. The way in which a plant cell differentiates is determined by the cell's position in the developing plant body. c. Homeotic genes often control morphogenesis. d. Plant cells differentiate because the cytoskeleton determines which genes will be turned "on" and "off." e. Arabidopsis was the first plant to have its genome sequenced.

Which of the following are true statements about the cells shown in the photograph in Figure 35.1 above? Select one: a. They are parenchyma cells. b. They are photosynthetic. c. They are usually found in roots. d. They are phloem cells. e. They are parenchyma cells and photosynthetic.

The following questions iare based on the drawing of root or stem cross sections shown in Figure 35.2. Figure 35.2 A monocot stem is represented by Select one: a. I only. b. II only. c. III only. d. IV only. e. both I and III.

The following questions iare based on the drawing of root or stem cross sections shown in Figure 35.2. Figure 35.2 A plant that is at least 3 years old is represented by Select one: a. I only. b. II only. c. III only. d. IV only. e. both I and III.

The following questions iare based on the drawing of root or stem cross sections shown in Figure 35.2. Figure 35.2 A woody eudicot is represented by Select one: a. I only. b. II only. c. III only. d. IV only. e. both I and III.

As a youngster, you drive a nail in the trunk of a young tree that is 3 meters tall. The nail is about 1.5 meters from the ground. Fifteen years later, you return and discover that the tree has grown to a height of 30 meters. About how many meters above the ground is the nail? Select one: a. 0.5 b. 1.5 c. 3.0 d. 15.0 e. 28.5

Most of the growth of a plant body is the result of Select one: a. cell differentiation. b. morphogenesis. c. cell division. d. cell elongation. e. reproduction.

The phase change of an apical meristem from the juvenile to the mature vegetative phase is often revealed by Select one: a. a change in the morphology of the leaves produced. b. the initiation of secondary growth. c. the formation of lateral roots. d. a change in the orientation of preprophase bands and cytoplasmic microtubules in lateral meristems. e. the activation of floral meristem identity genes.

Which of the following arise, directly or indirectly, from meristematic activity? Select one: a. secondary xylem b. leaves c. dermal tissue d. tubers e. secondary xylem, leaves, dermal tissue, and tubers

Which of the following would not be seen in a cross-section through the woody part of a root? Select one: a. sclerenchyma cells b. parenchyma cells c. sieve-tube elements d. root hairs e. vessel elements

All of the following are plant adaptations to life on land except Select one: a. tracheids and vessels. b. root hairs. c. cuticle. d. the Calvin cycle of photosynthesis. e. collenchyma.

If you were to prune the shoot tips of a plant, what would be the effect on the plant and the leaf area index? Select one: a. bushier plants; lower leaf area index b. tall plants; lower leaf area index c. tall plants; higher leaf area index d. short plants; lower leaf area index e. bushier plants; higher leaf area indexes

Which structure or compartment is not part of the plant's apoplast? Select one: a. the lumen of a xylem vessel b. the lumen of a sieve tube c. the cell wall of a mesophyll cell d. the cell wall of a transfer cell e. the cell wall of a root hair

Which of the following would be least likely to affect osmosis in plants? Select one: a. proton pumps in the membrane b. a difference in solute concentrations c. receptor proteins in the membrane d. aquaporins e. a difference in water potential

Active transport involves all of the following except the Select one: a. diffusion of solute through the lipid bilayer of a membrane. b. pumping of solutes across the membrane. c. hydrolysis of ATP. d. transport of solute against a concentration gradient. e. specific transport protein in the membrane.

Active transport of various materials in plants at the cellular level requires all of the following except Select one: a. a proton gradient. b. ATP. c. membrane potential. d. transport proteins e. xylem membranes.

Which of the following is not a function of the plasma membrane proton pump? Select one: a. hydrolyzes ATP b. produces a proton gradient c. generates a membrane potential d. equalizes the charge on each side of a membrane e. stores potential energy on one side of a membrane

Given that early land plants most likely share a common ancestor with green algae, the earliest land plants were most likely Select one: a. nonvascular plants that grew leafless photosynthetic shoots above the shallow fresh water in which they lived. b. species that did not exhibit alternation of generations. c. vascular plants with well-defined root systems. d. plants with well-developed leaves. e. species with a well-developed, thick cuticle.

The movement of water across biological membranes can best be predicted by Select one: a. negative charges in the cell wall. b. prevailing weather conditions. c. aquaporins. d. level of active transport. e. water potential.

Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will Select one: a. have a faster rate of osmosis. b. have a lower water potential. c. have a higher water potential. d. have a faster rate of active transport. e. be flaccid.

ome botanists argue that the entire plant should be considered as a single unit rather than a composite of many individual cells. Which of the following cellular structures cannot be used to support this view? Select one: a. cell wall b. cell membrane c. cytosol d. tonoplast e. symplast

Which of the following statements is false about bulk flow? Select one: a. It is driven primarily by pressure potential. b. It is more effective than diffusion over distances greater than 100 m. c. It depends on a difference in pressure potential at the source and sink. d. It depends on the force of gravity on a column of water. e. It may be the result of either positive or negative pressure potential.

Which of the following would likely not contribute to the surface area available for water absorption from the soil by a plant root system? Select one: a. root hairs b. endodermis c. mycorrhizae d. fungi associated with the roots e. fibrous arrangement of the roots

Root hairs are most important to a plant because they Select one: a. anchor a plant in the soil. b. store starches. c. increase the surface area for absorption. d. provide a habitat for nitrogen-fixing bacteria. e. contain xylem tissue.

A water molecule could move all the way through a plant from soil to root to leaf to air and pass through a living cell only once. This living cell would be a part of which structure? Select one: a. the Casparian strip b. a guard cell c. the root epidermis d. the endodermis e. the root cortex

All of the following involve active transport across membranes except Select one: a. the movement of mineral nutrients from the apoplast to the symplast. b. the movement of sugar from mesophyll cells into sieve-tube elements. c. the movement of sugar from one sieve-tube element to the next. d. the movement of K + across guard cell membranes during stomatal opening. e. the movement of mineral nutrients into cells of the root cortex.

Which of the following statements about xylem is incorrect? Select one: a. It conducts material from root tips to leaves. b. The conducting cells are part of the apoplast. c. It transports mainly sugars and amino acids. d. It typically has a lower water potential than is found in soil. e. No energy input is required for transport.

What is the role of proton pumps in root hair cells? Select one: a. establish ATP gradients b. maintain the H + gradient c. pressurize xylem transport d. eliminate excess electrons e. assist in active uptake of water molecules

In plant roots, the Casparian strip is correctly described by which of the following? Select one: a. It aids in the uptake of nutrients. b. It provides energy for the active transport of minerals into the stele from the cortex. c. It ensures that all minerals are absorbed from the soil in equal amounts. d. It ensures that all water and dissolved substances must pass through a cell membrane before entering the stele. e. It provides increased surface area for the absorption of mineral nutrients. Feedback

Which of the following is not an important component of the long-distance transport process in plants? Select one: a. the cohesion of water molecules b. a negative water potential c. the root parenchyma d. the active transport of solutes e. bulk flow from source to sink

Pine seedlings grown in sterile potting soil grow much slower than seedlings grown in soil from the area where the seeds were collected. This is most likely because Select one: a. the sterilization process kills the root hairs as they emerge from the seedling. b. the normal symbiotic fungi are not present in the sterilized soil. c. sterilization removes essential nutrients from the soil. d. water and mineral uptake is faster when mycorrhizae are present. e. the normal symbiotic fungi are not present in the sterilized soil and water and mineral uptake is faster when mycorrhizae are present.

The following factors may sometimes play a role in the movement of sap through xylem. Which one depends on the direct expenditure of ATP by the plant? Select one: a. capillarity of water within the xylem b. evaporation of water from leaves c. cohesion among water molecules d. concentration of ions in the symplast e. bulk flow of water in the root apoplast

One is most likely to see guttation in small plants when the Select one: a. transpiration rates are high. b. root pressure exceeds transpiration pull. c. preceding evening was hot, windy, and dry. d. water potential in the stele of the root is high. e. roots are not absorbing minerals from the soil.

One would expect to find the highest density of aquaporins in which of the following? Select one: a. the plasma membrane of guard cells b. the pits of a tracheid c. the plasma membrane of parenchyma cells in a ripe fruit d. the plasma membrane of a mature mesophyll cell in a leaf e. the membrane lining plasmodesmata

What drives the flow of water through the xylem? Select one: a. passive transport by the endodermis b. the number of companion cells in the phloem c. the evaporation of water from the leaves d. active transport by sieve-tube elements e. active transport by tracheid and vessel elements

What is the main force by which most of the water within xylem vessels moves toward the top of a tree? Select one: a. active transport of ions into the stele b. atmospheric pressure on roots c. evaporation of water through stoma d. the force of root pressure e. osmosis in the root

Which of the following is responsible for the cohesion of water molecules? Select one: a. hydrogen bonds between the oxygen atoms of a water molecule and cellulose in a vessel cell b. covalent bonds between the hydrogen atoms of two adjacent water molecules c. hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule d. covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule e. low concentrations of charged solutes in the fluid

Transpiration in plants requires all of the following except Select one: a. adhesion of water molecules to cellulose. b. cohesion between water molecules. c. evaporation of water molecules. d. active transport through xylem cells. e. transport through tracheids.

Which of the following statements about transport in plants is false? Select one: a. Weak bonding between water molecules and the walls of xylem vessels or tracheids helps support the columns of water in the xylem. b. Hydrogen bonding between water molecules, which results in the high cohesion of the water, is essential for the rise of water in tall trees. c. Although some angiosperm plants develop considerable root pressure, this is not sufficient to raise water to the tops of tall trees. d. Most plant physiologists now agree that the pull from the top of the plant resulting from transpiration is sufficient, when combined with the cohesion of water, to explain the rise of water in the xylem in even the tallest trees. e. Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.

Active transport would be least important in the normal functioning of which of the following plant tissue types? Select one: a. leaf transfer cells b. stem tracheary elements c. root endodermal cells d. leaf mesophyll cells e. root sieve-tube elementsstem tracheary elements

Which of the following statements is false concerning the xylem? Select one: a. Xylem tracheids and vessels fulfill their vital function only after their death. b. The cell walls of the tracheids are greatly strengthened with cellulose fibrils forming thickened rings or spirals. c. Water molecules are transpired from the cells of the leaves, and replaced by water molecules in the xylem pulled up from the roots due to the cohesion of water molecules. d. Movement of materials is by mass flow; solutes in xylary sap move due to a positive turgor pressure gradient from source to sink. e. In the morning, sap in the xylem begins to move first in the twigs of the upper portion of the tree, and later in the lower trunk.

Xylem vessels, found in angiosperms, have a much greater internal diameter than tracheids, the only xylem-conducting cells found in gymnosperms. The tallest living trees, redwoods, are gymnosperms. Which of the following is an advantage of tracheids over vessels for long-distance transport to great heights? Select one: a. Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders. b. The smaller the diameter of the xylem, the more likely cavitation will occur. c. Cohesive forces are greater in narrow tubes than in wide tubes of the same height. d. Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders, and cohesive forces are greater in narrow tubes than in wide tubes of the same height. e. Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders, and the smaller the diameter of the xylem, the more likely cavitation will occur.

Water rises in plants primarily by cohesion-tension. Which of the following is not true about the cohesion-tension model? Select one: a. Water loss (transpiration) is the driving force for water movement. b. The "tension" of this model represents the excitability of the xylem cells. c. Cohesion represents the tendency for water molecules to stick together by hydrogen bonds. d. The physical forces in the capillary-sized xylem cells make it easier to overcome gravity. e. The water potential of the air is more negative than the xylem.

Assume that a particular chemical interferes with the establishment and maintenance of proton gradients across the membranes of plant cells. All of the following processes would be directly affected by this chemical except Select one: a. photosynthesis. b. phloem loading. c. xylem transport. d. cellular respiration. e. stomatal opening.

Which cells in a root form a protective barrier to the vascular system where all materials must move through the symplast? Select one: a. pericycle b. cortex c. epidermis d. endodermis e. exodermis

Guard cells do which of the following? Select one: a. protect the endodermis b. accumulate K + and close the stomata c. contain chloroplasts that import K + directly into the cells d. guard against mineral loss through the stomata e. help balance the photosynthesis-transpiration compromise

All of the following normally enter the plant through the roots except Select one: a. carbon dioxide. b. nitrogen. c. potassium. d. water. e. calcium.

Photosynthesis begins to decline when leaves wilt because Select one: a. chloroplasts within wilted leaves are incapable of photosynthesis. b. CO 2 accumulates in the leaves and inhibits the enzymes needed for photosynthesis. c. there is insufficient water for photolysis during the light reactions. d. stomata close, restricting CO 2 entry into the leaf. e. wilted leaves cannot absorb the red and blue wavelengths of light.

The water lost during transpiration is a side effect of the plant's exchange of gases. However, the plant derives some benefit from this water loss in the form of Select one: a. evaporative cooling. b. mineral transport. c. increased turgor. d. increased growth, e. only evaporative cooling and mineral transport.

Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the leaves of a tree? Select one: a. cool, dry day b. warm, dry day c. warm, humid day d. cool, humid day e. very hot, dry, windy day

If the guard cells and surrounding epidermal cells in a plant are deficient in potassium ions, all of the following would occur except Select one: a. photosynthesis would decrease. b. roots would take up less water. c. phloem transport rates would decrease. d. leaf temperatures would decrease. e. stomata would be closed.

The opening of stomata is thought to involve Select one: a. an increase in the solute concentration of the guard cells. b. a decrease in the solute concentration of the stoma. c. active transport of water out of the guard cells. d. decreased turgor pressure in guard cells. e. movement of K + from the guard cells.

Which of the following experimental procedures would most likely reduce transpiration while allowing the normal growth of a plant? Select one: a. subjecting the leaves of the plant to a partial vacuum b. increasing the level of carbon dioxide around the plant c. putting the plant in drier soil d. decreasing the relative humidity around the plant e. injecting potassium ions into the guard cells of the plant

Guard cells are the only cells in the epidermis that contain chloroplasts and can undergo photosynthesis. This is important because Select one: a. chloroplasts sense when light is available so that guard cells will open. b. photosynthesis provides the energy necessary for contractile proteins to flex and open the guard cells. c. guard cells will produce the O 2 necessary to power active transport. d. ATP is required to power proton pumps in the guard cell membranes. e. chloroplasts sense when light is available so that guard cells will open and guard cells will produce the O 2 necessary to power active transport.

All of the following are adaptations that help reduce water loss from a plant except Select one: a. transpiration. b. sunken stomata. c. C 4 photosynthesis. d. small, thick leaves. e. crassulacean acid metabolism.

Which of the following best explains why very few CAM plants are tall? Select one: a. They have difficulty moving water and minerals to the top of the plant during the day. b. They would be unable to supply sufficient sucrose for active transport of minerals into the roots during the day or night. c. Transpiration occurs only at night, and this would cause a highly negative in the roots of a tall plant during the day. d. Since the stomata are closed in the leaves, the Casparian strip is closed in the endodermis of the root. e. With the stomata open at night, the transpiration rate would limit plant height.

As a biologist, it is your job to look for plants that have evolved structures with a selective advantage in dry, hot conditions. Which of the following adaptations would be least likely to meet your objective? Select one: a. CAM plants that grow rapidly b. small, thick leaves with stomata on the lower surface c. a thick cuticle on fleshy leaves d. large, fleshy stems with the ability to carry out photosynthesis e. plants that do not produce abscisic acid and have a short, thick taproot

A primary result for stomatal closure on a hot, dry day would be Select one: a. release of K + ions to the apoplast and subsidiary cells. b. displacement of Ca ++ ions from the thick inner walls of the guard cells. c. disassembly of the microfibrils in the cell walls of the subsidiary cells. d. upregulation of aquaporin synthesis. e. downregulation of extension proteins.

What is the driving force for the movement of solutes in the phloem of plants? Select one: a. gravity b. a difference in water potential ( ) between the source and the sink c. root pressure d. transpiration of water through the stomata e. adhesion of water to phloem sieve tubes

Phloem transport of sucrose is often described as going from source to sink. Which of the following would not normally function as a sink? Select one: a. growing leaf b. growing root c. storage organ in summer d. mature leaf e. shoot tip

Which of the following is a correct statement about sugar movement in phloem? Select one: a. Diffusion can account for the observed rates of transport. b. Movement can occur both upward and downward in the plant. c. Sugar is translocated from sinks to sources. d. Only phloem cells with nuclei can perform sugar movement. e. Sugar transport does not require energy.

Phloem transport is described as being from source to sink. Which of the following would most accurately complete this statement about phloem transport as applied to most plants in the late spring? Phloem transports ________ from the ________ source to the ________ sink. Select one: a. amino acids; root; mycorrhizae b. sugars; leaf; apical meristem c. nucleic acids; flower; root d. proteins; root; leaf e. sugars; stem; root

Arrange the following five events in an order that explains the mass flow of materials in the phloem. 1. Water diffuses into the sieve tubes. 2. Leaf cells produce sugar by photosynthesis. 3. Solutes are actively transported into sieve tubes. 4. Sugar is transported from cell to cell in the leaf. 5. Sugar moves down the stem. Select one: a. 2, 1, 4, 3, 5 b. 1, 2, 3, 4, 5 c. 2, 4, 3, 1, 5 d. 4, 2, 1, 3, 5 e. 2, 4, 1, 3, 5

Water flows into the source end of a sieve tube because Select one: a. sucrose has diffused into the sieve tube, making it hypertonic. b. sucrose has been actively transported into the sieve tube, making it hypertonic. c. water pressure outside the sieve tube forces in water. d. the companion cell of a sieve tube actively pumps in water. e. sucrose has been transported out of the sieve tube by active transport.

Which one of the following statements about transport of nutrients in phloem is false? Select one: a. Solute particles can be actively transported into phloem at the source. b. Companion cells control the rate and direction of movement of phloem sap. c. Differences in osmotic concentration at the source and sink cause a hydrostatic pressure gradient to be formed. d. A sink is that part of the plant where a particular solute is consumed or stored. e. A sink may be located anywhere in the plant.

According to the pressure flow hypothesis of phloem transport, Select one: a. solute moves from a high concentration in the source to a lower concentration in the sink. b. water is actively transported into the source region of the phloem to create the turgor pressure needed. c. the combination of a high turgor pressure in the source and transpiration water loss from the sink moves solutes through phloem conduits. d. the formation of starch from sugar in the sink increases the osmotic concentration. e. the pressure in the phloem of a root is normally greater than the pressure in the phloem of a leaf.

Plants do not have a circulatory system like that of some animals. If a water molecule did "circulate" (that is, go from one point in a plant to another and back in the same day), it would require the activity of Select one: a. only the xylem. b. only the phloem. c. only the endodermis. d. both the xylem and the endodermis. e. both the xylem and the phloem.

Plasmodesmata can change in number, and when dilated can provide a passageway for Select one: a. macromolecules such as RNA and proteins. b. ribosomes. c. chloroplasts. d. mitochondria. e. cytoskeletal components.

A fellow student brought in a leaf to be examined. The leaf was dark green, thin, had stoma on the lower surface only, and had a total surface area of 10 square meters. Where is the most likely environment where this leaf was growing? Select one: a. a dry, sandy region b. a large, still pond c. a tropical rain forest d. an oasis within a grassland e. the floor of a deciduous forest

Several tomato plants are growing in a small garden plot. If soil water potential were to drop significantly on a hot summer afternoon, which of the following would most likely occur? Select one: a. Stomatal apertures would decrease. b. Transpiration would increase. c. The leaves would become more turgid. d. The uptake of CO 2 would be enhanced. e. The proton gradient would dissipate.

The symplast transports all of the following except Select one: a. sugars. b. mRNA. c. DNA. d. proteins. e. viruses. Feedback

Which of the following is an adaptation that enhances the uptake of water and minerals by roots? Select one: a. mycorrhizae b. cavitation c. active uptake by vessel elements d. rhythmic contractions by cortical cells e. pumping through plasmodesmata

Which structure or compartment is part of the symplast? Select one: a. the interior of a vessel element b. the interior of a sieve tube c. the cell wall of a mesophyll cell d. an extracellular air space e. the cell wall of a root hair

Movement of phloem sap from a source to a sink Select one: a. occurs through the apoplast of sieve-tube elements. b. depends ultimately on the activity of proton pumps. c. depends on tension, or negative pressure potential. d. depends on pumping water into sieve tubes at the source. e. results mainly from diffusion.

Photosynthesis ceases when leaves wilt, mainly because Select one: a. the chlorophyll in wilting leaves is degraded. b. flaccid mesophyll cells are incapable of photosynthesis. c. stomata close, preventing CO 2 from entering the leaf. d. photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency. e. accumulation of CO 2 in the leaf inhibits enzymes.

What would enhance water uptake by a plant cell? Select one: a. decreasing the of the surrounding solution b. increasing the pressure exerted by the cell wall c. the loss of solutes from the cell d. increasing the of the cytoplasm e. positive pressure on the surrounding solution

Compared with a cell with few aquaporins in its membrane, a cell containing many aquaporins will Select one: a. have a faster rate of osmosis. b. have a lower water potential. c. have a higher water potential. d. have a faster rate of active transport. e. accumulate water by active transport.

Which of the following would tend to increase transpiration? Select one: a. a rainstorm b. sunken stomata c. a thicker cuticle d. higher stomatal density e. spiny leaves