Unit 8B Plants II

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Unit 8B Plants II

Multiple Choice
Identify the choice that best completes the statement or answers the question.

You are studying a plant from the arid southwestern United States. Which of the following adaptations is least likely to have evolved in response to water shortages?

a.	closing the stomata during the hottest time of the day
b.	development of large leaf surfaces to absorb water
c.	formation of a fibrous root system spread over a large area
d.	mycorrhizae associated with the root system
e.	a thick waxy cuticle on the epidermis

An evolutionary adaptation that increases exposure of a plant to light in a dense forest is

a.	closing of the stomata.
b.	lateral buds.
c.	apical dominance.
d.	absence of petioles.
e.	intercalary meristems.

A person working with plants may remove apical dominance by doing which of the following?

a.	pruning
b.	deep watering of the roots
c.	fertilizing
d.	transplanting
e.	feeding the plants nutrients

What effect does "pinching back" have on a houseplant?

a.	increases apical dominance
b.	inhibits the growth of lateral buds
c.	produces a plant that will grow taller
d.	produces a plant that will grow fuller
e.	increases the flow of auxin down the shoot

Land plants are composed of all the following tissue types except

a.	mesodermal.
b.	epidermal.
c.	meristematic.
d.	vascular.
e.	ground tissue.

Vascular plant tissue includes all of the following cell types except

a.	vessel elements.
b.	sieve cells.
c.	tracheids.
d.	companion cells.
e.	cambium cells.

Use the answers below to answer the following questions. Each answer may be used once, more than once, or not at all.

A.	parenchyma
B.	collenchyma
C.	sclerenchyma
D.	tracheids
E.	sieve cells

long, thin tapered cells with lignified cell walls that function in support and permit water to flow through pits

a.	A
b.	B
c.	C
d.	D
e.	E

the least specialized plant cells, which serve general metabolic, synthetic, and storage functions

a.	A
b.	B
c.	C
d.	D
e.	E

cells with unevenly thickened primary walls that support still-elongating parts of the plant

a.	A
b.	B
c.	C
d.	D
e.	E

10.

mature cells without protoplasts with thick, lignified secondary walls that may or may not function in transport

a.	A
b.	B
c.	C
d.	D
e.	E

11.

Which of the following is not a characteristic of parenchyma cells?

a.	thin primary walls
b.	flexible primary walls
c.	lack of specialization
d.	lack of secondary walls
e.	little metabolism and synthesis

12.

Which of the following tissues is incorrectly matched with its characteristics?

a.	collenchyma-uniformly thick-walled supportive tissue
b.	epidermis-protective outer covering of plant body
c.	sclerenchyma-heavily lignified secondary walls
d.	meristematic tissue-undifferentiated tissue capable of cell division
e.	parenchyma-thin-walled, loosely packed, unspecialized cells

13.

The fiber cells of plants are a type of

a.	parenchyma.
b.	sclerenchyma.
c.	collenchyma.
d.	meristematic cell.
e.	phloem

14.

The vascular bundle in the shape of a single central cylinder in a root is called the

a.	cortex.
b.	stele.
c.	endodermis.
d.	periderm.
e.	pith.

15.

One important difference between the anatomy of roots and the anatomy of leaves is that

a.	only leaves have phloem and only roots have xylem.
b.	the cells of roots have cell walls and leaf cells do not.
c.	a waxy cuticle covers leaves but is absent in roots.
d.	vascular tissue is found in roots but is absent from leaves.
e.	leaves have epidermal tissue but roots do not.

16.

The photosynthetic cells in the interior of a leaf are what kind of cells?

a.	parenchyma
b.	collenchyma
c.	sclerenchyma
d.	phloem
e.	endodermis

17.

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 these?

a.	parenchyma
b.	xylem
c.	endodermis
d.	collenchyma
e.	sclerenchyma

18.

The best word to describe the growth of plants in general is

a.	perennial.
b.	weedy.
c.	indeterminate.
d.	derivative.
e.	primary.

19.

A friend has discovered a new plant and brings it to you to classify. The plant has the following characteristics: a taproot system with growth rings evident in cross section and a layer of bark around the outside. Which of the following best describes the new plant?

a.	herbaceous eudicot
b.	woody eudicot
c.	woody monocot
d.	herbaceous monocot
e.	woody annual

20.

The driving force that pushes the root tip through the soil is due primarily to

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.	A and B only.
e.	A, B, and C.

21.

Shoot elongation in a growing bud is due primarily to

a.	cell division at the shoot apical meristem.
b.	cell elongation directly behind the shoot apical meristem.
c.	cell division localized in each internode.
d.	cell elongation localized in each internode.
e.	A and B only.

22.

Axillary buds

a.	are initiated by the cork cambium.
b.	develop from meristematic cells left by the apical meristem.
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.

I.	root cap
II.	zone of elongation
III.	zone of cell division
IV.	zone of cell maturation
V.	apical meristem

23.

Which of the following is the correct sequence from the growing tips of the root upward?

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

24.

Which of the following is incorrectly paired with its structure and function?

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

25.

Which of the following illustrates the idea that the fate of a cell is a direct result of its position?

a.	Some root epidermal cells form hairs; others do not.
b.	Floating leaves of Cabomba have a different shape than submerged leaves.
c.	Some shoot epidermal cells form stomata; others do not.
d.	A and C only
e.	A, B, and C

26.

Which of the following root tissues gives rise to lateral roots?

a.	endodermis
b.	phloem
c.	cortex
d.	epidermis
e.	pericycle

The following questions are based on the drawing of root or stem cross sections shown in the figure below.

27.

A woody eudicot is represented by

a.	I only.
b.	II only.
c.	III only.
d.	IV only.
e.	both I and III.

28.

A monocot stem is represented by

a.	I only.
b.	II only.
c.	III only.
d.	IV only.
e.	both I and III.

29.

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

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.	pre-prophase 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.

30.

Pores on the leaf surface that function in gas exchange are called

a.	hairs.
b.	xylem cells.
c.	phloem cells.
d.	stomata.
e.	sclereids.

31.

All of the following cell types are correctly matched with their functions except

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

32.

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 the tree has grown to a height of 30 meters. The nail is now ____ meters above the ground.

a.	0.5
b.	1.5
c.	3.0
d.	15.0
e.	28.5

33.

A short branch was cut into three segments as shown in the figure below to root some cuttings. Roots will form at which position(s)?

a.	A only
b.	A and B
c.	A, B, and C
d.	A, C, and E
e.	A, B, C, D, and E

34.

What tissue makes up most of the wood of a tree?

a.	primary xylem
b.	secondary xylem
c.	secondary phloem
d.	mesophyll cells
e.	vascular cambium

35.

The vascular system of a three-year-old eudicot stem consists of

a.	3 rings of xylem and 3 of phloem.
b.	2 rings of xylem and 2 of phloem.
c.	2 rings of xylem and 1 of phloem.
d.	2 rings of xylem and 3 of phloem.
e.	3 rings of xylem and 1 of phloem.

36.

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,

a.	the annual rings, phloem, and bark.
b.	the newest xylem, oldest 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.

37.

Bark becomes scaly because

a.	the cork cambium stops dividing in certain places.
b.	some cork cells die and slough off while others remain alive.
c.	ray parenchyma supplies only the "ridges" of bark.
d.	cork cambium divides only parallel to the surface, and thus does not increase in circumference.
e.	cork cambium has both ray and fusiform initials.

38.

Additional vascular tissue produced as secondary growth in a root originates from which cells?

a.	vascular cambium
b.	apical meristem
c.	endodermis
d.	phloem
e.	xylem

39.

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 information can be inferred?

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.

40.

Before differentiation can begin during the processes of plant cell and tissue culture, parenchyma cells from the source tissue must

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.

41.

The polarity of a plant is established when

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.

42.

Which of the following would be least likely to affect osmosis in plants?

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

43.

Which of the following is not a function of the plasma membrane proton pump?

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

44.

Which of the following is an example of osmosis?

a.	flow of water out of a cell
b.	pumping of water into a cell
c.	flow of water between cells
d.	both A and B
e.	both A and C

45.

The amount and direction of movement of water in plants can always be predicted by measuring which of the following?

a.	air pressure
b.	rainfall
c.	proton gradients
d.	dissolved solutes
e.	water potential ()

46.

Which of the following is true concerning the water potential of a plant cell?

a.	It is higher than that of air.
b.	It is equal to zero when the cell is in pure water and is turgid.
c.	It is equal to 0.23 MPa.
d.	It becomes higher when K⁺ is actively moved into the cell.
e.	It becomes lower after the uptake of water by osmosis.

47.

Your laboratory partner has an open beaker of pure water. By definition, the water potential (

) of this water is

a.	not meaningful, because it is an open beaker and not plant tissue.
b.	a negative number set by the volume of the beaker.
c.	a positive number set by the volume of the beaker.
d.	equal to the atmospheric pressure.
e.	zero.

48.

Which of the following has an effect on water potential (

) in plants?

a.	air pressure
b.	water-attracting matrices
c.	dissolved solutes
d.	A and C only
e.	A, B, and C

49.

P = 0.3 MPa and

S = -0.45 MPa, the resulting

a.	+0.75 MPa.
b.	-0.75 MPa.
c.	-0.15 MPa.
d.	+0.15 MPa.
e.	impossible to calculate with this information.

50.

The value for

in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (

= -0.23), net water flow would

a.	be from the tissue into the sucrose solution.
b.	be from the sucrose solution into the tissue.
c.	be in both directions and the concentrations would remain equal.
d.	occur only as ATP was hydrolyzed in the tissue.
e.	be impossible to determine from the values given here.

51.

Compared to a cell with few aquaporins in its membrane, a cell containing many aquaporins will

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.

52.

Some 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?

a.	cell wall
b.	cell membrane
c.	cytosol
d.	tonoplast
e.	symplast

53.

Which of the following statements about xylem is incorrect?

a.	It conducts material upward.
b.	It conducts materials within dead cells.
c.	It transports mainly sugars and amino acids.
d.	It has a lower water potential than soil does.
e.	No energy input from the plant is required for xylem transport.

54.

Which of the following would likely not contribute to the surface area available for water absorption from the soil by a plant root system?

a.	root hairs
b.	endodermis
c.	mycorrhizae
d.	fungi associated with the roots
e.	fibrous arrangement of the roots

55.

Root hairs are most important to a plant because they

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.

56.

What is the role of proton pumps in root hair cells?

a.	establish ATP gradients
b.	acquire minerals from the soil
c.	pressurize xylem transport
d.	eliminate excess electrons
e.	A and D only

57.

In plant roots, the Casparian strip is correctly described by which of the following?

a.	It is located in the walls between endodermal cells and cortex cells.
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 before entering the stele.
e.	It provides increased surface area for the absorption of mineral nutrients.

58.

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

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.	both B and D

59.

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?

a.	the Casparian strip
b.	a guard cell
c.	the root epidermis
d.	the endodermis
e.	the root cortex

60.

What is the main cause of guttation in plants?

a.	root pressure
b.	transpiration
c.	pressure flow in phloem
d.	plant injury
e.	condensation of atmospheric water

61.

One is most likely to see guttation in small plants when the

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.

62.

What is the main force by which most of the water within xylem vessels moves toward the top of a tree?

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

63.

Which of the following has the lowest (most negative) water potential?

a.	soil
b.	root xylem
c.	trunk xylem
d.	leaf cell walls
e.	leaf air spaces

64.

Transpiration in plants requires all of the following except

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.

65.

Which of the following statements about transport in plants is false?

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.

66.

Active transport would be least important in the normal functioning of which of the following plant tissue types?

a.	leaf transfer cells
b.	stem xylem
c.	root endodermis
d.	leaf mesophyll
e.	root phloem

67.

Which of the following statements is false concerning the xylem?

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; materials move owing to a 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.

68.

Guard cells do which of the following?

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

69.

All of the following normally enter the plant through the roots except

a.	carbon dioxide.
b.	nitrogen.
c.	potassium.
d.	water.
e.	calcium.

70.

The water lost during transpiration is an unfortunate side effect of the plant's exchange of gases. However, the plant derives some benefit from this water loss in the form of

a.	evaporative cooling.
b.	mineral transport.
c.	increased turgor.
d.	A and B only
e.	A, B, and C

71.

Ignoring all other factors, what kind of day would result in the fastest delivery of water and minerals to the leaves of a tree?

a.	cool, dry day
b.	warm, dry day
c.	warm, humid day
d.	cool, humid day
e.	very hot, dry, windy day

72.

If the guard cells and surrounding epidermal cells in a plant are deficient in potassium ions, all of the following would occur except

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.

73.

The opening of stomata is thought to involve

a.	an increase in the osmotic concentration of the guard cells.
b.	a decrease in the osmotic 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 guard cells.

74.

Which of the following experimental procedures would most likely reduce transpiration while allowing the normal growth of a plant?

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

75.

Guard cells are the only cells in the epidermis that contain chloroplasts and can undergo photosynthesis. This is important because

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 O₂ necessary to power active transport.
d.	ATP is required to power proton pumps in the guard cell membranes.
e.	both A and C

76.

All of the following are adaptations that help reduce water loss from a plant except

a.	transpiration.
b.	sunken stomata.
c.	C₄ photosynthesis.
d.	small, thick leaves.
e.	crassulacean acid metabolism.

77.

Which of the following best explains why CAM plants are not tall?

a.	They would be unable to move 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.

78.

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?

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 tap root

79.

Phloem transport of sucrose can be described as going from "source to sink." Which of the following would not normally function as a sink?

a.	growing leaf
b.	growing root
c.	storage organ in summer
d.	mature leaf
e.	shoot tip

80.

Which of the following is a correct statement about sugar movement in phloem?

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.

81.

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.

a.	amino acids; root; mycorrhizae
b.	sugars; leaf; apical meristem
c.	nucleic acids; flower; root
d.	proteins; root; leaf
e.	sugars; stem; root

82.

Water flows into the source end of a sieve tube because

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 dumped from the sieve tube by active transport.

83.

Which one of the following statements about transport of nutrients in phloem is false?

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.

84.

As predicted by the pressure flow hypothesis of translocation in plants, phloem exudates from the severed stylets of aphids near photosynthetic cells are sites of

a.	relatively high hydrostatic pressure.
b.	relatively low hydrostatic pressure.
c.	relatively high concentrations of organic nutrients.
d.	active pumping of sucrose out of the sieve tube.
e.	A and C only

85.

Plants do not have a circulatory system like that of some animals. If a given water molecule did "circulate" (that is, go from one point in a plant to another and back), it would require the activity of

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.

86.

In the pressure flow hypothesis of translocation, what causes the pressure?

a.	root pressure
b.	the osmotic uptake of water by sieve tubes at the source
c.	the accumulation of minerals and water by the stele in the root
d.	the osmotic uptake of water by the sieve tubes of the sink
e.	hydrostatic pressure in xylem vessels

87.

Most of the dry weight of a plant is the result of uptake of

a.	water and minerals through root hairs.
b.	water and minerals through mycorrhizae.
c.	CO₂ through stomata in leaves.
d.	CO₂ and O₂ through stomata in leaves.
e.	both A and B

88.

You are conducting an experiment on plant growth. You take a plant fresh from the soil that weighs 5 kg. Then you dry the plant overnight and determine the dry weight to be 1 kg. Of this dry weight, how much would you expect to be made up of inorganic minerals?

a.	1 gram
b.	5 grams
c.	50 grams
d.	75 grams
e.	1 kg

89.

In hydroponic culture, what is the purpose of bubbling air into the solute?

a.	to keep dissolved nutrients evenly distributed
b.	to provide oxygen to root cells
c.	to inhibit the growth of aerobic algae
d.	to inhibit the growth of anaerobic bacteria
e.	both C and D

90.

When performing a mineral nutrition experiment, researchers use water from a glass still. Why is it not a good idea to use regular distilled water from a stainless steel still?

a.	With a steel still, lime deposits from hard water will build up too quickly.
b.	Salts in the water corrode steel more quickly than glass.
c.	Metal ions dissolving off the steel may serve as micronutrients.
d.	A glass still allows the distillation process to be observed.
e.	There is no difference; both kinds of stills produce distilled water.

91.

Which of the following is of least concern to a researcher in a mineral nutrition experiment?

a.	purity of the chemicals used to make the nutrient solutions
b.	purity of the water used to make the nutrient solutions
c.	chemical inertness of the container used to make and store the nutrient solutions
d.	ability of a laboratory balance to weigh very small quantities of chemicals
e.	medium in which the test seedlings were grown

92.

Which two elements make up more than 90% of the dry weight of plants?

a.	carbon and nitrogen
b.	oxygen and hydrogen
c.	nitrogen and oxygen
d.	oxygen and carbon
e.	carbon and potassium

93.

The bulk of a plant's dry weight is derived from

a.	soil minerals.
b.	CO₂.
c.	the hydrogen from H₂O.
d.	the oxygen from H₂O.
e.	the uptake of organic nutrients from the soil.

94.

What are the three main elements on which plant growth and development depend?

a.	nitrogen; carbon; oxygen
b.	potassium; carbon; oxygen
c.	oxygen; carbon; hydrogen
d.	phosphorus; nitrogen; oxygen
e.	sulfur; nitrogen; phosphorus

95.

A growing plant exhibits chlorosis of the leaves of the entire plant. The chlorosis is probably due to a deficiency of which of the following macronutrients?

a.	carbon
b.	oxygen
c.	nitrogen
d.	calcium
e.	hydrogen

96.

Which of the following elements is incorrectly paired with its function in a plant?

a.	nitrogen—component of nucleic acids, proteins, hormones, coenzymes
b.	magnesium—component of chlorophyll; activates many enzymes
c.	phosphorus—component of nucleic acids, phospholipids, ATP, several coenzymes
d.	potassium—cofactor functional in protein synthesis; osmosis; operation of stomata
e.	sulfur—component of DNA; activates some enzymes

97.

In the nutrition of a plant, which element is classified as a macronutrient?

a.	zinc
b.	chlorine
c.	calcium
d.	molybdenum
e.	manganese

For the following questions, match the element to its major function in plants. Choices may be used more than once.

Function
A.	component of lignin-biosynthetic enzymes
B.	component of DNA and RNA
C.	active in chlorophyll formation
D.	active in amino acid formation
E.	formation and stability of cell walls

98.

nitrogen

a.	A
b.	B
c.	C
d.	D
e.	E

99.

copper

a.	A
b.	B
c.	C
d.	D
e.	E

100.

Reddish-purple coloring of leaves, especially along the margins of young leaves, is a typical symptom of deficiency of which element?

a.	C
b.	M⁺⁺
c.	N
d.	P
e.	K⁺

101.

Which of the following best describes the general role of micronutrients in plants?

a.	They are cofactors in enzymatic reactions.
b.	They are necessary for essential regulatory functions.
c.	They prevent chlorosis.
d.	They are components of nucleic acids.
e.	They are necessary for the formation of cell walls.

102.

Which of the following is not true of micronutrients in plants?

a.	They are the elements required in relatively small amounts.
b.	They are required for a plant to grow from a seed and complete its life cycle.
c.	They generally help in catalytic functions in the plant.
d.	They are the essential elements of small size and molecular weight.
e.	Overdoses of them can be toxic.

103.

If an African violet has chlorosis, which of the following elements might be a useful addition to the soil?

a.	chlorine
b.	molybdenum
c.	copper
d.	iodine
e.	magnesium

104.

Iron deficiency is often indicated by chlorosis in newly formed leaves. This suggests that

a.	iron is an immobile nutrient in plants.
b.	iron is tied up in formed chlorophyll molecules.
c.	the concentration of iron in the xylem sap decreases the further it is transported from the source in the soil.
d.	A and B only
e.	A, B, and C

105.

There are several properties of a soil in which typical plants would grow well. Of the following, which would be the least conducive to plant growth?

a.	abundant humus
b.	numerous soil organisms
c.	high clay content
d.	high porosity
e.	high cation exchange capacity

106.

A soil well suited for the growth of most plants would have all of the following properties except

a.	abundant humus.
b.	air spaces.
c.	good drainage.
d.	high cation exchange capacity.
e.	a high pH.

107.

What soil(s) is(are) the most fertile?

a.	humus only
b.	loam only
c.	silt only
d.	clay only
e.	both humus and loam

The figure below shows the results of a study to determine the effect of soil air spaces on plant growth. Use these data to answer the following questions.

108.

The best conclusion from the data in the figure above is that the plant

a.	grows best without air in the soil.
b.	grows fastest in 5 to 10% air.
c.	grows best in air levels above 15%.
d.	does not respond differently to different levels of air in the soil.
e.	would grow to 24 grams in 40% soil air.

109.

Why does overwatering a plant kill it?

a.	Water does not have all the necessary minerals a plant needs to grow.
b.	Water neutralizes the pH of the soil.
c.	The roots cannot get air.
d.	Water will attract parasites.
e.	Water will form hydrogen bonds with the root of the cell wall.

110.

All of the following contributed to the dust bowl in the American southwest during the 1930s except

a.	overgrazing by cattle.
b.	cutting of mature trees.
c.	plowing of native grasses.
d.	planting of field crops.
e.	lack of soil moisture.

111.

The N-P-K percentages on a package of fertilizer refer to the

a.	total protein content of the three major ingredients of the fertilizer.
b.	percentages of manure collected from different types of animals.
c.	relative percentages of organic and inorganic nutrients in the fertilizer.
d.	percentages of three important mineral nutrients.
e.	proportions of three different nitrogen sources.

Use the data below to answer the following questions.

In west Texas, cotton has become an important crop in the last several decades. However, in this hot, dry part of the country there is little rainfall, so farmers irrigate their cotton fields. They must also regularly fertilize the cotton fields because the soil is very sandy. The figure below shows the record of annual productivity (measured in kilograms of cotton per hectare of land) since 1960 in a west Texas cotton field.

112.

If you were the county agriculture agent, what would be the best advice you could give the farmer who owns the field under study in the figure above?

a.	Plant a variety of cotton that requires less water and can tolerate salinity.
b.	Continue to fertilize, but stop irrigating and rely on rainfall.
c.	Continue to irrigate, but stop fertilizing and rely on organic nutrients in the soil.
d.	Continue to fertilize and irrigate, but add the nitrogen-fixing bacteria Rhizobium to the irrigation water until the productivity increases.
e.	Add acid to the soil and increase its cation exchange capabilities so more nutrients are retained in the soil.

113.

A young farmer purchases some land in a relatively arid area and is interested in earning a reasonable profit for many years. Which of the following strategies would best allow such a goal to be achieved?

a.	establishing an extensive irrigation system
b.	using plenty of the best fertilizers
c.	finding a way to sell all parts of crop plants
d.	selecting crops adapted to arid areas
e.	converting hillsides into fields

114.

A farming commitment that embraces a variety of methods that are conservation-minded, environmentally safe, and profitable is called

a.	hydroponics.
b.	nitrogen fixation.
c.	responsible irrigation.
d.	genetic engineering.
e.	sustainable agriculture.

115.

An early use of indicator plants (plants that tolerate high levels of heavy metals in the soil) was to locate potential profitable areas to mine for those minerals. A current use for such plants is

a.	to help locate suitable sites for toxic waste storage.
b.	bioremediation to help clean up mine spoils.
c.	to minimize soil erosion in arid lands.
d.	nitrogen fixation by symbiotic bacteria in root nodules.
e.	all of the above

116.

Why is nitrogen fixation such an important process?

a.	Nitrogen fixation can only be done by certain prokaryotes.
b.	Fixed nitrogen is most often the limiting factor in plant growth.
c.	Nitrogen fixation is very expensive in terms of metabolic energy.
d.	Nitrogen fixers are sometimes symbiotic with legumes.
e.	Nitrogen-fixing capacity can be genetically engineered.

117.

Most crop plants acquire their nitrogen mainly in the form of

a.	NH₃.
b.	N₂.
c.	CN₂H₂.
d.	NO_3-.
e.	amino acids absorbed from the soil.

118.

In a root nodule, the gene coding for nitrogenase

a.	is inactivated by leghemoglobin.
b.	is absent in active bacteroids.
c.	is found in the cells of the pericycle.
d.	protects the nodule from nitrogen.
e.	is part of the Rhizobium chromosome.

119.

If a legume is infected with Rhizobium, what is the probable effect on the plant?

a.	It gets chlorosis.
b.	It dies.
c.	It desiccates.
d.	It obtains nitrogen from nitrogen fixation.
e.	It contributes water to the soil.

120.

You are weeding your garden when you accidentally expose some roots. You notice swellings (root nodules) on the roots. Most likely your plant

a.	suffers from a mineral deficiency.
b.	is infected with a parasite.
c.	is benefiting from a mutualistic bacterium.
d.	is developing offshoots from the root.
e.	contains developing insect pupa.

121.

Which of the following is a true statement about nitrogen fixation in root nodules?

a.	The plant contributes the nitrogenase enzyme.
b.	The process is relatively inexpensive in terms of ATP costs.
c.	Leghemoglobin helps maintain a low O₂ concentration within the nodule.
d.	The process tends to deplete nitrogen compounds in the soil.
e.	The bacteria of the nodule are autotrophic.

122.

The function of a root nodule's leghemoglobin is to

a.	extract macronutrients from the soil.
b.	regulate the supply of oxygen to Rhizobium.
c.	promote ion exchange in the soil.
d.	form a mutualistic relationship with insects.
e.	supply the legume with fixed nitrogen.

123.

How do legume plant roots communicate with Rhizobium bacteria?

a.	Flavonoids from Rhizobium create "nods."
b.	Plants activate early nodulin genes.
c.	Rhizobium secretes infection threads.
d.	Flavonoids trigger gene-regulating proteins in bacterium.
e.	Both A and C are correct.

124.

A woodlot was sprayed with a fungicide. What would be the most serious effect of such spraying?

a.	a decrease in food for animals that eat mushrooms
b.	an increase in rates of wood decay
c.	a decrease in tree growth due to the death of mycorrhizae
d.	an increase in the number of decomposing bacteria
e.	both A and B

125.

What is the mutualistic association between roots and fungi called?

a.	nitrogen fixation
b.	Rhizobium infection
c.	mycorrhizae
d.	parasitism
e.	root hair enhancement

126.

Hyphae form a covering over roots. Altogether, these hyphae create a large surface area that helps to do which of the following?

a.	aid in absorbing minerals and ions
b.	maintain cell shape
c.	increase cellular respiration
d.	anchor a plant
e.	protect the roots from ultraviolet light

127.

Which of the following is a primary difference between ectomycorrhizae and endomycorrhizae?

a.	Endomycorrhizae have thicker, shorter hyphae than ectomycorrhizae.
b.	Endomycorrhizae, but not ectomycorrhizae, form a dense sheath over the surface of the root.
c.	Ectomycorrhizae do not penetrate root cells, whereas endomycorrhizae grow into invaginations of the root cell membranes.
d.	Ectomycorrhizae are found in woody plant species; about 85% of plant families form ectomycorrhizae.
e.	There are no significant differences between ectomycorrhizae and endomycorrhizae.

128.

The earliest vascular plants on land had underground stems (rhizomes) but no roots. Water and mineral nutrients were most likely obtained by

a.	absorption by hairs and trichomes.
b.	diffusion through stomata.
c.	absorption by symbiotic fungi.
d.	osmosis through root hairs.
e.	diffusion across the cuticle of the rhizome.

129.

Dwarf mistletoe grows on many pine trees in the Rockies. Although the mistletoe is green, it is probably not sufficiently active in photosynthesis to produce all the sugar it needs. The mistletoe also produces haustoria. Thus, dwarf mistletoe growing on pine trees is best classified as

a.	an epiphyte.
b.	a nitrogen-fixing legume.
c.	a carnivorous plant.
d.	a symbiotic plant.
e.	a parasite.

130.

What are epiphytes?

a.	aerial vines common in tropical regions
b.	haustoria used for anchoring to host plants and obtaining xylem sap
c.	plants that live in poor soil and digest insects to obtain nitrogen
d.	plants that grow on other plants but do not obtain nutrients from their hosts
e.	plants that have a symbiotic relationship with fungi

131.

Carnivorous plants have evolved mechanisms that trap and digest small animals. The products of this digestion are used to supplement the plant's supply of

a.	energy.
b.	carbohydrates.
c.	lipids and steroids.
d.	minerals.
e.	water.

132.

The products of meiosis in plants are always which of the following?

a.	spores
b.	eggs
c.	sperm
d.	seeds
e.	both B and C

133.

Which of the following is the correct sequence during alternation of generations in a flowering plant?

a.	sporophyte-meiosis-gametophyte-gametes-fertilization-diploid zygote
b.	sporophyte-mitosis-gametophyte-meiosis-sporophyte
c.	haploid gametophyte-gametes-meiosis-fertilization-diploid sporophyte
d.	sporophyte-spores-meiosis-gametophyte-gametes
e.	haploid sporophyte-spores-fertilization-diploid gametophyte

134.

Which of the following is true in plants?

a.	Meiosis occurs in gametophytes to produce gametes.
b.	Meiosis occurs in sporophytes to produce spores.
c.	The gametophyte is the dominant generation in flowering plants.
d.	Plants exist continually as either sporophytes or gametophytes.
e.	Male gametophytes and female gametophytes have the same structure.

135.

All of the following are features of angiosperms except

a.	a triploid endosperm.
b.	an ovary that becomes a fruit.
c.	animal pollination.
d.	a small (reduced) sporophyte.
e.	double fertilization.

136.

Based on studies of plant evolution, which flower part is not a modified leaf?

a.	stamen
b.	carpel
c.	petal
d.	sepal
e.	receptacle

137.

All of the following floral parts are directly involved in pollination or fertilization except the

a.	stigma.
b.	anther.
c.	sepal.
d.	carpel.
e.	style.

138.

A mutation in which of the following floral parts would have the greatest impact on pollination?

a.	sepal
b.	petal
c.	stamen
d.	carpel
e.	either C or D

139.

A mutation in which of the following floral parts would have the greatest potential impact on fertilization?

a.	sepal
b.	petal
c.	stamen
d.	carpel
e.	either C or D

140.

Which of the following is the correct order of floral organs from the outside to the inside of a complete flower?

a.	petals-sepals-stamens-carpels
b.	sepals-stamens-petals-carpels
c.	spores-gametes-zygote-embryo
d.	sepals-petals-stamens-carpels
e.	male gametophyte-female gametophyte-sepals-petals

141.

Meiosis occurs within all of the following flower parts except the

a.	ovule.
b.	style.
c.	megasporangium.
d.	anther.
e.	ovary.

142.

A perfect flower is fertile, but may be either complete or incomplete. Which of the following correctly describes a perfect flower?

a.	It has no sepals.
b.	It has fused carpels.
c.	It is on a dioecious plant.
d.	It has no endosperm.
e.	It has both stamens and carpels.

143.

Carpellate flowers

a.	are perfect.
b.	are complete.
c.	produce pollen.
d.	are found only on dioecious plants.
e.	develop into fruits.

144.

Which of the following types of plants is not able to self-pollinate?

a.	dioecious
b.	monoecious
c.	complete
d.	wind-pollinated
e.	insect-pollinated

145.

Where does meiosis occur in flowering plants?

a.	megasporocyte
b.	microsporocyte
c.	endosperm
d.	pollen tube
e.	megasporocyte and microsporocyte

146.

Which of the following is a correct sequence of processes that takes place when a flowering plant reproduces?

a.	meiosis-fertilization-ovulation-germination
b.	fertilization-meiosis-nuclear fusion-formation of embryo and endosperm
c.	meiosis-pollination-nuclear fusion-formation of embryo and endosperm
d.	growth of pollen tube-pollination-germination-fertilization
e.	meiosis-mitosis-nuclear fusion-pollen

147.

Which of these is incorrectly paired with its life-cycle generation?

a.	anther—gametophyte
b.	pollen—gametophyte
c.	embryo sac—gametophyte
d.	stamen—sporophyte
e.	embryo—sporophyte

148.

Which of the following is the correct sequence of events in a pollen sac?

a.	sporangia—meiosis—two haploid cells—meiosis—two pollen grains per cell
b.	pollen grain—meiosis—two generative cells—two tube cells per pollen grain
c.	two haploid cells—meiosis—generative cell—tube cell-fertilization—pollen grain
d.	pollen grain—mitosis—microspores—meiosis—generative cell plus tube cell
e.	microsporocyte-meiosis-microspores-mitosis-two haploid cells per pollen grain

149.

Which of the following occurs in an angiosperm ovule?

a.	An antheridium forms from the megasporophyte.
b.	A megaspore mother cell undergoes meiosis.
c.	The egg nucleus is usually diploid.
d.	A pollen tube emerges to accept pollen after pollination.
e.	The endosperm surrounds the megaspore mother cell.

150.

Where and by which process are sperm produced in plants?

a.	meiosis in pollen grains
b.	meiosis in anthers
c.	mitosis in male gametophytes
d.	mitosis in the micropyle
e.	mitosis in the embryo sac

151.

Which of the following is the male gametophyte of a flowering plant?

a.	ovule
b.	microsporocyte
c.	pollen grain
d.	embryo sac
e.	stamen

152.

In flowering plants, a mature male gametophyte contains

a.	two haploid gametes and a diploid pollen grain.
b.	a generative cell and a tube cell.
c.	two sperm nuclei and one tube cell nucleus.
d.	two haploid microspores.
e.	a haploid nucleus and a diploid pollen wall.

153.

The largest cell(s) of the typical angiosperm embryo sac is (are) the

a.	egg cell.
b.	antipodals.
c.	synergids.
d.	central cell.
e.	microsporocyte.

The following questions refer to the diagram of an embryo sac of an angiosperm.

154.

Which cell(s), after fertilization, give(s) rise to the embryo plant?

a.	A
b.	B
c.	C
d.	D
e.	E

155.

Which cell(s) become(s) the triploid endosperm?

a.	A
b.	B
c.	C
d.	D
e.	E

156.

Which cell(s) guide(s) the pollen tube to the egg cell?

a.	A
b.	B
c.	C
d.	D
e.	E

157.

What is the relationship between pollination and fertilization in flowering plants?

a.	Fertilization precedes pollination.
b.	Pollination easily occurs between plants of different species.
c.	Pollen is formed within megasporangia so that male and female gametes are near each other.
d.	Pollination brings gametophytes together so that fertilization can occur.
e.	If fertilization occurs, pollination is unnecessary.

158.

Recent research has shown that pollination requires that carpels recognize pollen grains as "self or nonself." For self-incompatibility, the system requires

a.	rejection of nonself cells.
b.	the rejection of self cells.
c.	carpel incompatibility with the egg cells.
d.	that the flowers be incomplete.
e.	the union of genetically identical sperm and egg cells.

159.

Genetic incompatibility does not affect the

a.	attraction of a suitable insect pollinator.
b.	germination of the pollen on the stigma.
c.	growth of the pollen tube in the style.
d.	membrane permeability of cells.
e.	different individuals of the same species.

160.

As flowers develop, which transition does not occur?

a.	The microspores become pollen grains.
b.	The ovary becomes a fruit.
c.	The petals are discarded.
d.	The tube nucleus becomes a sperm nucleus.
e.	The ovules become seeds.

161.

The integuments of an ovule function to do what?

a.	protect against animal predation
b.	ensure double fertilization
c.	form a seed coat
d.	both A and B
e.	both A and C

162.

Which of the following events suggests there is a change in the egg cell membrane after penetration by a sperm?

a.	The pollen tube grows away from the egg toward the polar nuclei.
b.	Ca²⁺ builds up in the cytoplasm of the egg.
c.	The egg cell plasmolyzes.
d.	Double fertilization occurs.
e.	All of the above are correct.

163.

A fruit includes

a.	one or more seeds.
b.	the ovary wall.
c.	fleshy cells rich in sugars.
d.	brightly colored pigments to attract animal dispersers.
e.	both A and B

164.

Which of the following is not an advantage of an extended gametophyte generation in plants?

a.	Male gametophytes can travel more easily within spore walls.
b.	The protection of female gametophytes within ovules keeps them from drying out.
c.	The lack of need for swimming sperm makes life on land easier.
d.	Female gametophytes develop egg cells, which are fertilized within an ovule that will become a seed.
e.	Endosperm forms a protective seed coat.

165.

What is typically the result of double fertilization in angiosperms?

a.	The endosperm develops into a diploid nutrient tissue.
b.	A triploid zygote is formed.
c.	Both a diploid embryo and triploid endosperm are formed.
d.	Two embryos develop in every seed.
e.	The fertilized antipodal cells develop into the seed coat.

166.

Which of the following statements regarding the endosperm is false?

a.	Its nutrients may be absorbed by the cotyledons in the seeds of eudicots.
b.	It develops from a triploid cell.
c.	Its nutrients are digested by enzymes in monocot seeds following hydration.
d.	It develops from the fertilized egg.
e.	It is rich in nutrients, which it provides to the embryo.

167.

In angiosperms, products of the terminal cell become the

a.	suspensor.
b.	proembryo.
c.	cotyledons.
d.	suspensor and the proembryo.
e.	proembryo and the cotyledons.

168.

Which of the following statements is correct about the basal cell in a zygote?

a.	It develops into the root of the embryo.
b.	It forms the suspensor that anchors the embryo.
c.	It results directly from the fertilization of the polar nuclei by a sperm nucleus.
d.	It divides and initiates the two cotyledons.
e.	It forms the proembryo.

169.

Which of these structures is unique to the seed of a monocot?

a.	cotyledon
b.	endosperm
c.	coleoptile
d.	radicle
e.	seed coat

170.

Which of the following statements about fruits is false?

a.	Fruits form from microsporangia and integuments.
b.	All normal fruits have seeds inside them.
c.	Green beans, corn, tomatoes, and wheat are all fruits.
d.	Fruits aid in the dispersal of seeds.
e.	During fruit development, the wall of the ovary becomes the pericarp.

171.

Fruits develop from

a.	microsporangia.
b.	receptacles.
c.	fertilized eggs.
d.	ovaries.
e.	ovules.

172.

Which of the following is not true of the hypocotyl hook?

a.	It is the first structure to emerge from a eudicot seed.
b.	It pulls the cotyledons up through the soil.
c.	It straightens when exposed to light.
d.	It becomes very long in an etiolated seedling.
e.	It is the region just below the cotyledons.

173.

In plants, which of the following could be an advantage of sexual reproduction as opposed to asexual reproduction?

a.	genetic variation
b.	mitosis
c.	stable populations
d.	rapid population increase
e.	greater longevity

174.

A disadvantage of monoculture is that

a.	the whole crop ripens at one time.
b.	genetic uniformity makes a crop vulnerable to a new pest or disease.
c.	it predominantly uses vegetative propagation.
d.	most grain crops self-pollinate.
e.	it allows for the cultivation of large areas of land.

175.

Which of the following is a true statement about clonal reproduction in plants?

a.	Clones of plants do not occur naturally.
b.	Cloning, although achieved in animals, has not been demonstrated in plants.
c.	Making cuttings of ornamental plants is a form of fragmentation.
d.	Reproduction of plants by cloning may be either sexual or asexual.
e.	Viable seeds can result from sexual reproduction only.

176.

All of the following could be considered advantages of asexual reproduction in plants except

a.	success in a stable environment.
b.	increased agricultural productivity.
c.	cloning an exceptional plant.
d.	production of artificial seeds.
e.	adaptation to change.

177.

Regardless of where in the world a vineyard is located, in order for the winery to produce a Burgundy, it must use varietal grapes that originated in Burgundy, France. The most effective way for a new California grower to plant a vineyard to produce Burgundy is to

a.	plant seeds obtained from French varietal Burgundy grapes.
b.	transplant varietal Burgundy plants from France.
c.	root cuttings of varietal Burgundy grapes from France.
d.	cross French Burgundy grapes with native American grapes.
e.	graft varietal Burgundy grape scions onto native (Californian) root stocks.

178.

Which of the following statements is true of protoplast fusion?

a.	It occurs when the second sperm nucleus fuses with the polar nuclei in the embryo sac.
b.	It can be used to form new plant varieties by combining genomes from two plants.
c.	It is used to develop gene banks to preserve genetic variability.
d.	It is the method of test-tube cloning that produces whole plants from explants.
e.	It occurs within a callus that is developing in tissue culture.

179.

Which of the following statements is correct about protoplast fusion?

a.	It is used to develop gene banks to maintain genetic variability.
b.	It is the method of test-tube cloning thousands of copies.
c.	It can be used to form new plant species.
d.	It occurs within a callus.
e.	It requires that the cell wall remain intact during the fusion process.

180.

Typical cultivated maize is homozygous for the dominant alleles of the opaque-2 gene and deficient in lysine. Conventional breeding required almost 20 years to introduce the recessive opaque-2 genes into maize. Which of the following statements is false?

a.	All of the characteristics found in the original opaque-2 mutant plant were desirable.
b.	Modern maize varieties containing opaque-2 are genetically modified.
c.	None of the F₁ progeny from a cross of an opaque-2 mutant and a normal maize plant will express the opaque-2 character.
d.	It takes three growing seasons to determine which F₁ progeny have a recessive parental trait when one parent is the recessive mutant and the other is wild-type.
e.	Both C and D are false.

181.

Which of the following statements is true about transgenic plants?

a.	They can be produced only by genetic engineering.
b.	They contain genes from more than one species.
c.	Intermediate species are required for transgenic plants to be produced.
d.	They require many years to be produced.
e.	A and D are correct statements.

182.

Which of the following is not a scientific concern relating to creating genetically modified crops?

a.	Herbicide resistance may spread to weedy species.
b.	Insect pests may evolve resistance to toxins more rapidly.
c.	Nontarget species may be affected.
d.	The monetary costs of growing genetically modified plants are significantly greater than traditional breeding techniques.
e.	Genetically modified plants may lead to unknown risks to human health.

183.

Which of the following statements about genetic engineering is (are) true?

a.	Genes can only be transferred between closely related species.
b.	Intermediate species are necessary to transfer genes between unrelated species.
c.	Cell and protoplast culture techniques simplify the process of inserting modified genes into a plant species.
d.	Only A and B are correct.
e.	A, B, and C are correct.

184.

Currently available transgenic plants have been modified for all of the following traits except

a.	insect resistance.
b.	nitrogen fixation.
c.	herbicide resistance.
d.	improved nutritional quality.
e.	virus resistance.

185.

In modern agriculture, what does "terminator technology" refer to?

a.	introduction of bacterial genes that release insect toxins into plants
b.	introduction of male sterility genes into plants to prevent selfing
c.	introduction of genes into a plant that prevent its seeds from maturing
d.	Bt genes produced in maize pollen
e.	selection of resistant clones following mutator treatment of seeds

186.

The step(s) between a plant's perception of a change in the environment and the plant's response to that change is (are) best called

a.	a mutation.
b.	hormone production.
c.	pH change.
d.	signal transduction.
e.	an "all-or-none" response.

187.

Which of the following statements is (are) true of plants?

a.	Unlike animals, plants cannot respond to stimuli.
b.	Plants are stationary and are incapable of movement.
c.	Plants adjust their growth and development in response to environmental cues.
d.	Only A and B are true.
e.	A, B, and C are true.

188.

External stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the

a.	cell membrane.
b.	cytoplasmic matrix.
c.	endoplasmic reticulum.
d.	nuclear membrane.
e.	nucleoplasm.

189.

Secondary messengers are associated with which of the following?

a.	reception
b.	transduction
c.	response
d.	both A and B
e.	both B and C

190.

What would happen if the secondary messenger cGMP was blocked in the de-etiolation pathway?

a.	Specific protein kinase 1 would be activated, and greening would occur.
b.	Ca²⁺ channels would not open, and no greening would occur.
c.	Ca²⁺ channels could open, and specific protein kinase 2 could still be produced.
d.	No transcription of genes that function in de-etiolation would occur.
e.	Transcription of de-etiolation genes in the nucleus would not be affected.

191.

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the

a.	tip of the coleoptile.
b.	part of the coleoptile that bends during the response.
c.	root tip.
d.	cotyledon.
e.	phytochrome.

192.

Plants growing in a partially dark environment will grow toward light in a response called phototropism. Choose the incorrect statement regarding phototropism.

a.	It is caused by a chemical signal.
b.	One chemical involved is auxin.
c.	Auxin causes a growth increase on one side of the stem.
d.	Auxin causes a decrease in growth on the side of the stem exposed to light.
e.	Removing the apical meristem prevents phototropism.

193.

Which of these conclusions is supported by the research of both Went and Charles and Frances Darwin on shoot responses to light?

a.	When shoots are exposed to light, a chemical substance migrates toward the light.
b.	Agar contains a chemical substance that mimics a plant hormone.
c.	A chemical substance involved in shoot bending is produced in shoot tips.
d.	Once shoot tips have been cut, normal growth cannot be induced.
e.	Light stimulates the synthesis of a plant hormone that responds to light.

194.

We know from the experiments of the past that plants bend toward light because

a.	they need sunlight energy for photosynthesis.
b.	the sun stimulates stem growth.
c.	cell expansion is greater on the dark side of the stem.
d.	auxin is inactive on the dark side of the stem.
e.	phytochrome stimulates florigen production.

195.

Which of the following is not presently considered a major mechanism whereby hormones control plant development?

a.	affecting cell respiration via regulation of the citric acid cycle
b.	affecting cell division via the cell cycle
c.	affecting cell elongation through acid growth
d.	affecting cell differentiation through altered gene activity
e.	mediating short-term physiological responses to environmental stimuli

196.

Evidence for phototropism due to the asymmetric distribution of auxin moving down the stem

a.	has not been found in eudicots such as sunflower and radish.
b.	has been found in all monocots and most eudicots.
c.	has been shown to involve only IAA stimulation of cell elongation on the dark side of the stem.
d.	can be demonstrated with unilateral red light, but not blue light.
e.	is now thought by most plant scientists not to involve the shoot tip.

197.

Vines in tropical rain forests must grow toward large trees before being able to grow toward the sun. To reach a large tree, the most useful kind of growth movement for a tropical vine presumably would be the opposite of

a.	positive thigmotropism.
b.	positive phototropism.
c.	positive gravitropism.
d.	sleep movements.
e.	circadian rhythms.

198.

Plant hormones can be characterized by all of the following except that they

a.	may act by altering gene expression.
b.	have a multiplicity of effects.
c.	function independently of other hormones.
d.	control plant growth and development.
e.	affect division, elongation, and differentiation of cells.

199.

Plant hormones produce their effects by

a.	altering the expression of genes.
b.	modifying the permeability of the plasma membrane.
c.	modifying the structure of the nuclear envelope membrane.
d.	both A and B.
e.	both B and C only

200.

Why is it so difficult to study the actions of plant hormones?

a.	Their effects are often the result of an interaction of hormones.
b.	They are found in small quantities in the plant.
c.	We probably have not discovered all of them.
d.	They sometimes cause different responses in different plants.
e.	All of the above make the study of plant hormones difficult.

201.

Plant hormones can have different effects at different concentrations. This explains how

a.	some plants are long-day plants and others are short-day plants.
b.	signal transduction pathways in plants are different from those in animals.
c.	plant genes recognize pathogen genes.
d.	auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds.
e.	they really don't fit the definition of "hormone."

202.

Which plant hormones might be used to enhance stem elongation and fruit growth?

a.	brassinosteroids and oligosaccharides
b.	auxins and gibberellins
c.	abscisic acid and phytochrome
d.	ethylene and cytokinins
e.	phytochrome and flowering hormone

203.

Which of the following has not been established as an aspect of auxin's role in cell elongation?

a.	Auxin instigates a loosening of cell wall fibers.
b.	Auxin increases the quantity of cytoplasm in the cell.
c.	Through auxin activity, vacuoles increase in size.
d.	Auxin activity permits an increase in turgor pressure.
e.	Auxin stimulates proton pumps.

204.

Which of the following hormones would be most useful in promoting the rooting of plant cuttings?

a.	oligosaccharins
b.	abscisic acid
c.	cytokinins
d.	gibberellins
e.	auxins

205.

Which plant hormone(s) is (are) most closely associated with cell division?

a.	ethylene
b.	cytokinin
c.	abscisic acid
d.	phytochrome
e.	brassinosteroids

206.

The heavy line in the figure below illustrates the relationship between auxin concentration and cell growth in stem tissues. If the same range of concentrations were applied to lateral buds, what curve would probably be produced?

a.	I
b.	II
c.	III
d.	II and III
e.	either I or III

207.

The application of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants?

a.	indoleacetic acid
b.	cytokinin
c.	gibberellin
d.	abscisic acid
e.	ethylene

Refer to the figure below to answer the following questions.

208.

The results of this experiment, shown on the left of the graph (area A), may be used to

a.	show that these plants can live without gibberellin.
b.	show that gibberellin is necessary in positive gravitropism.
c.	show that taller plants with more gibberellin produce fruit (pods).
d.	show a correlation between plant height and gibberellin concentration.
e.	study phytoalexins in plants.

209.

One effect of gibberellins is to stimulate cereal seeds to produce

a.	RuBP carboxylase.
b.	lipids.
c.	abscisic acid.
d.	starch.
e.	amylase.

210.

In attempting to make a seed break dormancy, one logically could treat it with

a.	IAA.
b.	2, 4-D.
c.	CO₂.
d.	gibberellins.
e.	abscisic acid.

211.

Ethylene, as an example of a plant hormone, may have multiple effects on a plant, depending on all of the following except the

a.	site of action within the plant.
b.	developmental stage of the plant.
c.	concentration of ethylene.
d.	altered chemical structure of ethylene from a gas to a liquid.
e.	readiness of cell membrane receptors for the ethylene.

212.

If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?

a.	CO₂
b.	cytokinins
c.	ethylene
d.	auxin
e.	gibberellic acids

213.

Which of the following is currently the most powerful method of research on plant hormones?

a.	comparing of photoperiodic responses
b.	comparing tropisms with turgor movements
c.	subjecting plants to unusual stresses
d.	studying phytochromes
e.	analyzing mutant plants

214.

Auxin is responsible for all of the following plant growth responses except

a.	phototropism.
b.	formation of adventitious roots.
c.	apical dominance.
d.	the detection of photoperiod.
e.	cell elongation.

215.

Incandescent light bulbs, which have high output of red light, are least effective in promoting

a.	photosynthesis.
b.	seed germination.
c.	phototropism.
d.	flowering.
e.	entrainment of circadian rhythms.

216.

Both red and blue light are involved in

a.	stem elongation.
b.	photoperiodism.
c.	positive phototropism.
d.	tracking seasons.
e.	all of the above

217.

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only 1/4 inch of soil is that the

a.	seedlings do not produce a hypocotyl.
b.	seedlings do not have an etiolation response.
c.	seeds require light to germinate.
d.	seeds require a higher temperature to germinate.
e.	seeds are very sensitive to waterlogging.

218.

Most plants close their stomata at night. What color of light would be most effective in promoting stomatal opening in the middle of the night?

a.	red
b.	far-red
c.	blue
d.	red followed by far-red
e.	far-red followed by blue

219.

In legumes, it has been shown that "sleep" movements are correlated with

a.	positive thigmotropisms.
b.	rhythmic opening and closing of K⁺ channels in motor cell membranes.
c.	senescence (the aging process in plants).
d.	flowering and fruit development.
e.	ABA-stimulated closing of guard cells caused by loss of K⁺.

220.

Biological clocks cause organisms to perform daily activities on a regular basis. Which of the following is a false statement about this kind of "circadian rhythm"?

a.	It may have the same signal transduction pathway in all organisms.
b.	It must be reset on a daily basis.
c.	It may help to cause photoperiodic responses.
d.	Once set, it is independent of external signals.
e.	The exact mechanism of biological clocks remains unknown.

221.

The biological clock controlling circadian rhythms must ultimately

a.	depend on environmental cues.
b.	affect gene transcription.
c.	stabilize on a 24-hour cycle.
d.	speed up or slow down with increasing or decreasing temperature.
e.	do all of the above.

222.

Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes

a.	are more predictable than air temperature changes.
b.	alter the amount of energy available to the plant.
c.	are modified by soil temperature changes.
d.	can reset the biological clock.
e.	are correlated with moisture availability.

223.

If the range of a species of plants expands to a higher latitude, which of the following processes is the most likely to be modified by natural selection?

a.	circadian rhythm
b.	photoperiodic response
c.	phototropic response
d.	biological clock
e.	thigmomorphogenesis

224.

In nature, poinsettias bloom in early March. Research has shown that the flowering process is triggered three months before blooming occurs. In order to make poinsettias bloom in December, florists change the length of the light-dark cycle in September. Given the information and clues above, which of the following is a false statement about poinsettias?

a.	They are short-day plants.
b.	They require a light period shorter than some set maximum.
c.	They require a longer dark period than is available in September.
d.	The dark period can be interrupted without affecting flowering.
e.	They will flower even if there are brief periods of dark during the daytime.

225.

A botanist exposed two groups of the same plant species to two photoperiods-one with 14 hours of light and 10 hours of dark and the other with 10 hours of light and 14 hours of dark. Under the first set of conditions, the plants flowered, but they failed to flower under the second set of conditions. Which of the following conclusions would be consistent with these results?

a.	The critical night length is 14 hours.
b.	The plants are short-day plants.
c.	The critical day length is 10 hours.
d.	The plants can convert phytochrome to florigen.
e.	The plants flower in the spring.

226.

In order to flower, a short-day plant needs a

a.	burst of red light in the middle of the night.
b.	burst of far-red light in the middle of the night.
c.	day that is longer than a certain length.
d.	night that is longer than a certain length.
e.	higher ratio of Pr to Pfr.

227.

If a short-day plant has a critical night length of 15 hours, then which of the following 24-hour cycles will prevent flowering?

a.	8 hours light/16 hours dark
b.	4 hours light/20 hours dark
c.	6 hours light/2 hours dark/light flash/16 hours dark
d.	8 hours light/8 hours dark/light flash/8 hours dark
e.	2 hours light/20 hours dark/2 hours light

228.

A long-day plant will flower if

a.	the duration of continuous light exceeds a critical length.
b.	the duration of continuous light is less than a critical length.
c.	the duration of continuous darkness exceeds a critical length.
d.	the duration of continuous darkness is less than a critical length.
e.	it is kept in continuous far-red light.

229.

Plants that have their flowering inhibited by being exposed to bright lights at night are

a.	day-neutral plants.
b.	short-night plants.
c.	devoid of phytochrome.
d.	short-day plants.
e.	long-day plants.

230.

Suppose there is a large deciduous ornamental tree on your campus and the city places a very bright street light right next to it on a tall pole. A botanist on the faculty complains to the city council and asks them to remove the light. Most likely the botanist is concerned because the light

a.	will alter the photosynthetic rate of the tree and keep it growing at night.
b.	may cause the stomata to close because of increased ABA synthesis. This could starve the tree for CO₂ and it could die.
c.	may change the photoperiod and cause the tree to retain its leaves during the winter. This could cause dehydration and loss of the tree.
d.	will cause the tree to bend toward the light on the pole, and the tree could fall.
e.	will stimulate ethylene production, premature senescence, and early death of the tree.

231.

If you take a short-day plant and put it in a lab under conditions where it will flower (long nights and short days), but interrupt its day period with a few minutes of darkness, what will happen?

a.	It will flower.
b.	It will not flower.
c.	It will die.
d.	It will lose its ability to photosynthesize.
e.	It will form new shoots from the axillary buds.

232.

Florigen is a flowering signal, not yet chemically identified, found in

a.	flowers.
b.	leaves.
c.	roots.
d.	seeds.
e.	floral buds.

233.

What do results of research on gravitropic responses of roots and stems show?

a.	Different tissues have the same response to auxin.
b.	The effect of a plant hormone can depend on the tissue.
c.	Some responses of plants require no hormones at all.
d.	Light is required for the gravitropic response.
e.	Cytokinin can only function in the presence of auxin.

234.

A botanist discovers a plant that lacks the ability to form starch grains in root cells, yet the roots still grow downward. This evidence refutes the long-standing hypothesis that

a.	falling statoliths trigger gravitropism.
b.	starch accumulation triggers the negative phototropic response of roots.
c.	starch grains block the acid growth response in roots.
d.	starch is converted to auxin, which causes the downward bending in roots.
e.	starch and downward movement are necessary for thigmotropism.

235.

If a plant is mechanically stimulated, it will grow shorter, thicker stems. This response is

a.	the result of ethylene production.
b.	caused by an increase in turgor.
c.	an adaptation to windy environments.
d.	A and C only
e.	A, B, and C

236.

When transplanting a tree, it is recommended to loosely attach three or four guylines. The purpose of leaving these supports loose is to

a.	prevent constriction of secondary growth.
b.	permit moderate bending to stimulate thickness growth.
c.	allow room for expansion as the tree grows taller.
d.	B and C only
e.	A, B, and C

237.

Which of the following watering regimens will be most effective at keeping a lawn green during the hot, dry summer months?

a.	daily sprinkling to soak the soil to 0.5 inch
b.	sprinkling every other day to soak the soil to 1.0 inch
c.	sprinkling every third day to soak the soil to 2.0 inches
d.	A or B would be equally effective.
e.	A, B or C would be equally effective.

238.

You are part of a desert plant research team trying to discover crops that will be productive in arid climates. You discover a plant that produces a guard cell hormone under water-deficit conditions. Most likely the hormone is

a.	ABA.
b.	GA.
c.	IAA.
d.	2, 4-D.
e.	salicylic acid.

239.

Plant cells begin synthesizing large quantities of heat-shock proteins

a.	after the induction of chaperone proteins.
b.	in response to the lack of CO₂ following the closing of stomata by ethylene.
c.	when desert plants are quickly removed from high temperatures.
d.	when they are subjected to moist heat (steam) followed by electric shock.
e.	when the air around species from temperate regions is above 40°C.

240.

Most scientists agree that global warming is underway; thus it is important to know how plants respond to heat stress. Which of the following is an immediate short-term response of plants to heat stress?

a.	the production of heat-shock carbohydrates unique to each plant
b.	the production of heat-shock proteins like those of other organisms
c.	the opening of stomata to increase evaporational heat loss
d.	their evolution into more xerophytic plants
e.	all of the above

241.

In extremely cold regions, woody species may survive freezing temperatures by

a.	emptying water from the vacuoles to prevent freezing.
b.	decreasing the numbers of phospholipids in cell membranes.
c.	decreasing the fluidity of all cellular membranes.
d.	producing canavanine as a natural antifreeze.
e.	increasing cytoplasmic levels of specific solute concentrations, such as sugars.

242.

All of the following are responses of plants to cold stress except

a.	the production of a specific solute "plant antifreeze" that reduces water loss.
b.	excluding ice crystals from the interior walls.
c.	conversion of the fluid mosaic cell membrane to a solid mosaic one.
d.	an alteration of membrane lipids so that the membranes remain flexible.
e.	increasing the proportion of unsaturated fatty acids in the membranes.

243.

Bald cypress and Loblolly pine are both gymnosperm trees native to the southern United States. The cypress grows in swamps; the pine grows in sandy soil. How do you think their anatomies differ?

a.	There are larger intercellular spaces in the roots of the cypress than in the roots of the pine.
b.	Water-conducting cells are larger in the stems of the cypress than in the stems of the pine.
c.	The springwood and summerwood are more distinct in the cypress.
d.	There is less parenchyma in the roots of the cypress than in the pine roots.
e.	There are no major anatomical differences between these species because they're both gymnosperms.

244.

The initial response of the root cells of a tomato plant watered with seawater would be to

a.	rapidly produce organic solutes in the cytoplasm.
b.	rapidly expand until the cells burst.
c.	begin to plasmolyze as water is lost.
d.	actively transport water from the cytoplasm into the vacuole.
e.	actively absorb salts from the seawater.

245.

In order for a plant to initiate chemical responses to herbivory,

a.	the plant must be directly attacked by an herbivore.
b.	volatile "signal" compounds must be perceived.
c.	gene-for-gene recognition must occur.
d.	phytoalexins must be released.
e.	all of the above must happen.

246.

Plants are affected by an array of pathogens. Which of the following is not a plant defense against disease?

a.	cells near the point of infection destroying themselves to prevent the spread of the infection
b.	production of chemicals that kill pathogens
c.	acquiring gene-for-gene recognition that allows specific proteins to interact so that the plant can produce defenses against the pathogen
d.	a waxy cuticle that pathogens have trouble penetrating
e.	All of the above are plant defenses against disease.

247.

A pathogenic fungus invades a plant. What does the infected plant produce in response to the attack?

a.	antisense RNA
b.	phytoalexins
c.	phytochrome
d.	statoliths
e.	thickened cellulose microfibrils in the cell wall

248.

Which of the following are defenses that some plants use against herbivory?

a.	production of the unusual amino acid canavanine
b.	release of volatile compounds that attract parasitoid wasps
c.	association of plant tissues with mycorrhizae
d.	A and B only
e.	A, B, and C

249.

Which of the following are examples or parts of plants' systemic acquired resistance against infection?

a.	phytoalexins
b.	salicylic acid
c.	alarm hormones
d.	A and B only
e.	A, B, and C

250.

When an arborist prunes a limb off a valuable tree, he or she usually paints the cut surface. The primary purpose of the paint is to

a.	minimize water loss by evaporation from the cut surface.
b.	improve the appearance of the cut surface.
c.	stimulate growth of the cork cambium to "heal" the wound.
d.	block entry of pathogens through the wound.
e.	induce the production of phytoalexins.