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Biology Exit Exam

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created 2 years ago by Soon2BNurse
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1

Which structure is incorrectly paired with its tissue system?

a) root hair-dermal tissue

b) palisade parenchyma-ground tissue

c) guard cell-dermal tissue

d) companion cell-ground tissue

e) tracheid-vascular tissue

d

2

Which of the following is derived from the ground tissue system?

a) root hairs

b) cuticle

c) periderm

d) pith

e) phloem

d

3

All of the following are plant adaptations to life on land except

a) tracheids and vessels.

b) root hairs.

c) cuticle.

d) the Calvin cycle of photosynthesis.

e) collenchyma

e

4

Which part of a plant absorbs most of the water and minerals taken up from the soil?

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

b

5

Land plants are composed of all the following tissue types except

a) mesodermal.

b) epidermal.

c) meristematic.

d) vascular.

e) ground tissue.

a

6

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.

e

7

CO2 enters the inner the spaces of the leaf through the

a) cuticle.

b) epidermal trichomes.

c) stoma.

d) phloem.

e) walls of guard cells.

c

8

Which of the following have thick, lignified walls that help support mature, nongrowing parts of the plant?

a) parenchyma cells

b) collenchyma cells

c) clerenchyma cells

d) tracheids and vessel elements

e) sieve-tube elements

c

9

Plants contain meristems whose only function is to

a) attract pollinators.

b) absorb ions.

c) photosynthesize.

d) divide.

e) produce flowers

d

10

Gas exchange, necessary for photosynthesis, can occur most easily in which leaf tissue?

a) epidermis

b) palisade mesophyll

c) spongy mesophyll

d) vascular tissue

e) bundle sheath

c

11

Which structure or compartment is not part of the plant's apoplast?

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

b

12

Active transport involves all of the following except the

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) a specific transport protein in the membrane.

a

13

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

a) pressure potential

b) number of aquaporins

c) proton gradients

d) dissolved solutes

e) water potential (ψ)

e

14

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

b

15

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) B and D

e

16

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

d

17

Water rises in plants primarily by the cohesion-tension model. Which of the following is not true about this model?

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.

b

18

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

a) photosynthesis.

b) phloem loading.

c) xylem transport.

d) cellular respiration.

e) stomatal opening.

c

19

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

e

20

Why does over-watering 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 are deprived of oxygen.

d) Water supports the growth of root parasites.

e) Water lowers the water potential of the roots

c

21

What should be added to soil to prevent minerals from leaching away?

a) humus

b) sand

c) mycorrhizae

d) nitrogen

e) silt

a

22

Which soil mineral is most likely leached away during a hard rain?

a) Na+

b) K+

c) Ca++

d) NO3-

e) H+

d

23

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.

e

24

Some plants extract and concentrate heavy metals from the soil. A current use for such plants is

a) to help locate suitable sites for toxic waste storage.

b) to concentrate rare metals for medicinal use.

c) to minimize soil erosion in arid lands.

d) nitrogen fixation by symbiotic bacteria in root nodules.

e) photoremediation of polluted sites

e

25

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 stoma.

d) CO2 and O2 through stomata in leaves.

e) carbohydrates in the root hairs and concentration in the root cortex

c

26

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

d

27

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

c

28

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

c

29

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

c

30

Nitrogen fixation is a process that

a) recycles nitrogen compounds from dead and decaying materials.

b) converts ammonia to nitrate.

c) releases nitrate from the rock substrate.

d) converts nitrogen gas into ammonia.

e) A and B

d

31

What is the mutualistic association between roots and fungi called?

a) nitrogen fixation

b) Rhizobium infection

c) mycorrhizae

d) parasitism

e) root hair enhancement

c

32

All of the following are part of a prokaryotic cell except

a) DNA.

b) a cell wall.

c) a plasma membrane.

d) ribosomes.

e) an endoplasmic reticulum

e

33

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that

a) plant cells are capable of having a much higher surface-to-volume ratio than animal cells.

b) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells.

c) plant cells contain a large vacuole that reduces the volume of the cytoplasm.

d) animal cells are more spherical, while plant cells are elongated.

e) the basic functions of plant cells are very different from those of animal cells.

c

34

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

a) lipids

b) starches

c) proteins

d) steroids

e) glucose

c

35

Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?

a) ribosome

b) lysosome

c) smooth endoplasmic reticulum

d) mitochondrion

e) contractile vacuole

c

36

Which structure is the site of the synthesis of proteins that may be exported from the cell?

a) rough ER

b) lysosomes

c) plasmodesmata

d) Golgi vesicles

e) tight junctions

a

37

The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity?

a) Transport vesicles fuse with one side of the Golgi and leave from the opposite side.

b) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi tothe other.

c) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.

d) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.

e) All of the above correctly describe polar characteristics of the Golgi function.

e

38

In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization?

a) chloroplast

b) lysosome

c) central vacuole

d) peroxisome

e) glyoxysome

b

39

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?

a) rough ER

b) smooth ER

c) Golgi apparatus

d) Nuclear envelope

e) Transport vesicles

b

40

Which of the following produces and modifies polysaccharides that will be secreted?

a) lysosome

b) vacuole

c) mitochondrion

d) Golgi apparatus

e) peroxisome

d

41

Which is one of the main energy transformers of cells?

a) lysosome

b) vacuole

c) mitochondrion

d) Golgi apparatus

e) peroxisome

c

42

Which of the following contains its own DNA and ribosomes?

a) lysosome

b) vacuole

c) mitochondrion

d) Golgi apparatus

e) peroxisome

c

43

Which of the following contains enzymes that transfer hydrogen from various substrates to oxygen?

a) lysosome

b) vacuole

c) mitochondrion

d) Golgi apparatus

e) peroxisome

e

44

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

a) They can move laterally along the plane of the membrane.

b) They frequently flip-flop from one side of the membrane to the other.

c) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane.

d) They are free to depart from the membrane and dissolve in the surrounding solution.

e) They have hydrophilic tails in the interior of the membrane

a

45

In order for a protein to be an integral membrane protein it would have to be which of the following?

a) hydrophilic

b) hydrophobic

c) amphipathic

d) completely covered with phospholipids

e) exposed on only one surface of the membrane

c

46

When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are

a) peripheral proteins.

b) phospholipids.

c) carbohydrates.

d) integral proteins.

e) cholesterol molecules

d

47

Chloride ion channels are membrane structures that include which of the following?

a) gap junctions

b) aquaporins

c) hydrophilic proteins

d) carbohydrates

e) sodium ions

c

48

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells?

a) The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution.

b) The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution.

c) The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution.

d) The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution.

e) The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution.

d

49

When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur?

a) the cell will burst

b) the cell membrane will lyse

c) plasmolysis will shrink the interior

d) the cell will become flaccid

e) the cell will become turgid

e

50

An organism with a cell wall would have the most difficulty doing which process?

a) diffusion

b) osmosis

c) active transport

d) phagocytosis

e) facilitated diffusion

d

51

White blood cells engulf bacteria through what process?

a) exocytosis

b) phagocytosis

c) pinocytosis

d) osmosis

e) receptor-mediated exocytosis

b

52

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

a) catalysis

b) metabolism

c) anabolism

d) dehydration

e) catabolism

e

53

Which of the following is (are) true for anabolic pathways?

a) They do not depend on enzymes.

b) They are usually highly spontaneous chemical reactions.

c) They consume energy to build up polymers from monomers.

d) They release energy as they degrade polymers to monomers.

c

54

Which of the following types of reactions would decrease the entropy within a cell?

a) dehydration reactions

b) hydrolysis

c) respiration

d) digestion

e) catabolism

a

55

Which of the following is considered an open system?

a) an organism

b) liquid in a corked bottle

c) a sealed terrarium

d) food cooking in a pressure cooker

a

56

A chemical reaction that has a positive △G is correctly described as

a) endergonic.

b) endothermic.

c) enthalpic.

d) spontaneous.

e) exothermic

a

57

When 10,000 molecules of ATP are hydrolyzed to ADP and Pi in a test tube, about twice as much heat is liberated aswhen a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation?

a) Cells are open systems, but a test tube is a closed system.

b) Cells are less efficient at heat production than nonliving systems.

c) The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube.

d) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes.

e) Reactant and product concentrations are not the same

e

58

Which of the following is most similar in structure to ATP?

a) an anabolic steroid

b) a DNA helix

c) an RNA nucleotide

d) an amino acid with three phosphate groups attached

e) a phospholipid

c

59

Which of the following statements is (are) true about enzyme-catalyzed reactions?

a) The reaction is faster than the same reaction in the absence of the enzyme.

b) The free energy change of the reaction is opposite from the reaction in the absence of the enzyme.

c) The reaction always goes in the direction toward chemical equilibrium.

d) A and B only

e) A, B, and C

a

60

In order to attach a particular amino acid to the tRNA molecule that will transport it, an enzyme, an aminoacyl-tRNA synthetase, is required, along with ATP. Initially, the enzyme has an active site for ATP and another for the amino acid, but it is not able to attach the tRNA. What must occur in order for the final attachment to occur?

a) The ATP must first have to attach to the tRNA.

b) The binding of the first two molecules must cause a 3-dimensional change that opens another active site on the enzyme.

c) The hydrolysis of the ATP must be needed to allow the amino acid to bind to the synthetase.

d) The tRNA molecule must have to alter its shape in order to be able to fit into the active site with the other twomolecules.

e) The 3' end of the tRNA must have to be cleaved before it can have an attached amino acid

b

61

Which of the following is likely to lead to an increase in the concentration of ATP in a cell?

a) an increase in a cell's anabolic activity

b) an increase in a cell's catabolic activity

c) an increased influx of cofactor molecules

d) an increased amino acid concentration

e) the cell's increased transport of materials to the environment

b

62

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

a) anabolic pathways

b) catabolic pathways

c) fermentation pathways

d) thermodynamic pathways

e) bioenergetic pathways

b

63

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction

a) gains electrons and gains energy.

b) loses electrons and loses energy.

c) gains electrons and loses energy.

d) loses electrons and gains energy.

e) neither gains nor loses electrons, but gains or loses energy.

b

64

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes

a) dehydrogenated.

b) hydrogenated.

c) oxidized.

d) reduced.

e) an oxidizing agent.

c

65

Where does glycolysis takes place?

a) mitochondrial matrix

b) mitochondrial outer membrane

c) mitochondrial inner membrane

d) mitochondrial intermembrane space

e) cytosol

e

66

The oxygen consumed during cellular respiration is involved directly in which process or event?

a) glycolysis

b) accepting electrons at the end of the electron transport chain

c) the citric acid cycle

d) the oxidation of pyruvate to acetyl CoA

e) the phosphorylation of ADP to form ATP

b

67

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

a) electron transport

b) glycolysis

c) the citric acid cycle

d) oxidative phosphorylation

e) chemiosmosis

b

68

How does pyruvate enter the mitochondrion?

a) active transport

b) diffusion

c) facilitated diffusion

d) through a channel

e) through a pore

a

69

Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid?

a) succinate

b) malate

c) citrate

d) α-ketoglutarate

e) isocitrate

d

70

The primary role of oxygen in cellular respiration is to

a) yield energy in the form of ATP as it is passed down the respiratory chain.

b) act as an acceptor for electrons and hydrogen, forming water.

c) combine with carbon, forming CO2.

d) combine with lactate, forming pyruvate.

e) catalyze the reactions of glycolysis

b

71

Energy released by the electron transport chain is used to pump H+ ions into which location?

a) cytosol

b) mitochondrial outer membrane

c) mitochondrial inner membrane

d) mitochondrial intermembrane space

e) mitochondrial matrix

d

72

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is

a) oxidation of glucose to CO2 and water.

b) the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers.

c) the final transfer of electrons to oxygen.

d) the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane.

e) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.

d

73

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

a) It produces much less ATP than does oxidative phosphorylation.

b) It is found in the cytosol, does not involve oxygen, and is present in most organisms.

c) It is found in prokaryotic cells but not in eukaryotic cells.

d) It relies on chemiosmosis which is a metabolic mechanism present only in the first cells-prokaryotic cells.

e) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.

b

74

If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one is

a) PGA.

b) PGAL.

c) glucose.

d) RuBP.

e) O2.

e

75

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

a) CO2 and glucose

b) H2O and O2

c) ADP, Pi, and NADP+

d) electrons and H+

e) ATP and NADPH

e

76

The reaction-center chlorophyll of photosystem I is known as P700 because

a) there are 700 chlorophyll molecules in the center.

b) this pigment is best at absorbing light with a wavelength of 700 nm.

c) there are 700 photosystem I components to each chloroplast.

d) it absorbs 700 photons per microsecond.

e) the plastoquinone reflects light with a wavelength of 700 nm

b

77

Which of the events listed below occur in the light reactions of photosynthesis?

a) NADP is produced.

b) NADPH is reduced to NADP+.

c) carbon dioxide is incorporated into PGA.

d) ATP is phosphorylated to yield ADP.

e) light is absorbed and funneled to reaction-center chlorophyll a.

e

78

What are the products of linear photophosphorylation?

a) heat and fluorescence

b) ATP and P700

c) ATP and NADPH

d) ADP and NADP

e) P700 and P680

c

79

Synthesis of ATP by the chemiosmotic mechanism occurs during

a) photosynthesis.

b) respiration.

c) both photosynthesis and respiration.

d) neither photosynthesis nor respiration.

e) photorespiration.

c

80

Reduction of oxygen which forms water occurs during

a) photosynthesis.

b) respiration.

c) both photosynthesis and respiration.

d) neither photosynthesis nor respiration.

e) photorespiration.

b

81

Requires ATP

a) light reactions alone

b) the Calvin cycle alone

c) both the light reactions and the Calvin cycle

d) neither the light reactions nor the Calvin cycle

e) occurs in the chloroplast but is not part of photosynthesis

b

82

Produces NADH

a) light reactions alone

b) the Calvin cycle alone

c) both the light reactions and the Calvin cycle

d) neither the light reactions nor the Calvin cycle

e) occurs in the chloroplast but is not part of photosynthesis

d

83

Why are C4 plants able to photosynthesize with no apparent photorespiration?

a) They do not participate in the Calvin cycle.

b) They use PEP carboxylase to initially fix CO2.

c) They are adapted to cold, wet climates.

d) They conserve water more efficiently.

e) They exclude oxygen from their tissues.

b

84

If plant gene alterations cause the plants to be deficient in photorespiration, what would most probably occur?

a) Cells would carry on more photosynthesis.

b) Cells would carry on the Calvin cycle at a much slower rate.

c) Less ATP would be generated.

d) There would be more light-induced damage to the cells.

e) More sugars would be produced

c

85

Paracrine signaling

a) involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid.

b) requires nerve cells to release a neurotransmitter into the synapse.

c) occurs only in paracrine yeast cells.

d) has been found in plants but not animals.

e) involves mating factors attaching to target cells and causing production of new paracrine cells.

a

86

Which of the following is (are) true of ligand-gated ion channels?

a) They are important in the nervous system.

b) They lead to changes in sodium and calcium concentrations in cells.

c) They open or close in response to a chemical signal.

d) Only A and B are true.

e) A, B, and C are true.

e

87

Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to

a) the active site of an allosteric enzyme in the cytoplasm that binds to a specific substrate.

b) RNA specifying the amino acids in a polypeptide.

c) a particular metabolic pathway operating within a specific organelle.

d) an enzyme with an optimum pH and temperature for activity.

e) genes making up a chromosome

a

88

Chemical signal pathways

a) operate in animals, but not in plants.

b) are absent in bacteria, but are plentiful in yeast.

c) involve the release of hormones into the blood.

d) often involve the binding of signal molecules to a protein on the surface of a target cell.

e) use hydrophilic molecules to activate enzymes.

d

89

The general name for an enzyme that transfers phosphate groups from ATP to a protein is

a) phosphorylase.

b) phosphatase.

c) protein kinase.

d) ATPase.

e) protease.

c

90

Which of the following is a correct association?

a) kinase activity and the addition of a tyrosine

b) phosphodiesterase activity and the removal of phosphate groups

c) GTPase activity and hydrolysis of GTP to GDP

d) phosphorylase activity and the catabolism of glucose

e) adenylyl cyclase activity and the conversion of cAMP to AMP

c

91

What are scaffolding proteins?

a) ladder-like proteins that allow receptor-ligand complexes to climb through cells from one position to another

b) microtubular protein arrays that allow lipid-soluble hormones to get from the cell membrane to the nuclear pores

c) large molecules to which several relay proteins attach to facilitate cascade effects

d) relay proteins that orient receptors and their ligands in appropriate directions to facilitate their complexing

e) proteins that can reach into the nucleus of a cell to affect transcription

c

92

Tissues are composed of cells, and tissues functioning together make up

a) organs.

b) membranes.

c) organ systems.

d) organelles.

e) organisms.

a

93

An exchange surface is in direct contact with the external environment in the

a) lungs.

b) skeletal muscles.

c) liver.

d) heart.

e) brain.

a

94

An example of a connective tissue is the

a) skin.

b) nerves.

c) blood.

d) cuboidal epithelium.

e) smooth muscles

c

95

Stratified cuboidal epithelium is composed of

a) several layers of box-like cells.

b) a hierarchical arrangement of flat cells.

c) a tight layer of square cells attached to a basement membrane.

d) an irregularly arranged layer of pillar-like cells.

e) a layer of ciliated, mucus-secreting cells.

a

96

Fibroblasts secrete

a) fats.

b) chondroitin sulfate.

c) interstitial fluids.

d) calcium phosphate for bone.

e) proteins for connective fibers.

e

97

Muscles are joined to bones by

a) ligaments.

b) tendons.

c) loose connective tissue.

d) Haversian systems.

e) spindle fibers.

b

98

The type of muscle tissue associated with internal organs, other than the heart, is

a) skeletal muscle.

b) cardiac muscle.

c) striated muscle.

d) intercalated cells.

e) smooth muscle

e

99

An example of a properly functioning homeostatic control system is seen when

a) the core body temperature of a runner rises gradually from 37°C to 45°C.

b) the kidneys excrete salt into the urine when dietary salt levels rise.

c) a blood cell shrinks when placed in a solution of salt and water.

d) the blood pressure increases in response to an increase in blood volume.

e) the level of glucose in the blood is abnormally high whether or not a meal has been eaten

b

100

Positive feedback differs from negative feedback in that

a) positive feedback benefits the organism, whereas negative feedback is detrimental.

b) the effector's response in positive feedback is in the same direction as the initiating stimulus rather than opposite to it.

c) the effector's response increases some parameter (such as temperature), whereas in negative feedback it decreases.

d) positive feedback systems have only effectors, whereas negative feedback systems have only receptors.

e) positive feedback systems have control centers that are lacking in negative feedback systems.

b

101

An ectotherm is more likely to survive an extended period of food deprivation than would an equally-sized endotherm because

a) the ectotherm maintains a higher basal metabolic rate.

b) the ectotherm expends more energy/kg body weight than the endotherm.

c) the ectotherm invests little energy in temperature regulation.

d) the ectotherm metabolizes its stored energy more readily than can the endotherm.

e) the ectotherm has greater insulation on its body surface

c

102

Standard metabolic rate (SMR) and basal metabolic rate (BMR)

a) are used differently: SMR is measured during exercise, while BMR is measured at rest.

b) are used to compare metabolic rate between hibernating and non-hibernating states.

c) are both measured across a wide range of temperatures for a given species.

d) are both standard measurements of mammals.

e) are both measured in animals in a resting and fasting state.

e

103

Hibernation and estivation are both examples of

a) acclimatization.

b) torpor.

c) evaporative cooling.

d) non-shivering thermogenesis.

e) shivering thermogenesis

b

104

The body is capable of catabolizing many substances as sources of energy. Which of the following would be used as an energy source only after the depletion of other sources?

a) fat in adipose tissue

b) glucose in the blood

c) protein in muscle cells

d) glycogen in muscle cells

e) calcium phosphate in bone

c

105

Which of the following minerals is associated with its use in animals?

a) calcium - construction and maintenance of bone

b) magnesium - cofactor in enzymes that make ATP

c) iron - necessary for thyroid function

d) sulfur - ingredient of nucleic acids

e) iodine - important in nerve function

a

106

Folic acid supplements have become especially important for pregnant women. Why?

a) Folic acid supplies vitamins that pregnant women lose.

b) The folic acid stored by pregnant women is removed from their circulation.

c) The fetus makes high levels of folic acid.

d) Folic acid deprivation is associated with neural tube abnormalities in a fetus.

e) Folic acid deprivation is a cause of heart abnormalities in a newborn

d

107

To leave the digestive tract, a substance must cross a cell membrane. During which stage of food processing does this take place?

a) ingestion

b) digestion

c) hydrolysis

d) absorption

e) elimination

d

108

Increasing the surface area directly facilitates which of the following digestive processes?

a) hydrolysis

b) absorption

c) elimination

d) A and B only

e) A, B, and C

d

109

What part(s) of the digestive system have secretions with a pH of 2?

a) small intestine

b) stomach

c) pancreas

d) liver

e) mouth

b

110

Which of the following is a nutritional monomer that can be transported in the blood?

a) sucrose

b) maltose

c) fatty acid

d) dipeptide

e) trinucleotide

c

111

In which group of animals would you expect to find a relatively long cecum?

a) carnivores

b) herbivores

c) autotrophs

d) heterotrophs

e) omnivores

b

112

Leptin is a product of adipose cells. Therefore, a very obese mouse would be expected to have which of the following?

a) increased gene expression of ob and decreased expression of db

b) increased gene expression of db and decreased expression of ob

c) decreased transcription of both ob and db

d) mutation of ob or db

d

113

Organisms in which a circulating body fluid is distinct from the fluid that directly surrounds the body's cells are likely to have which of the following?

a) an open circulatory system

b) a closed circulatory system

c) a gastrovascular cavity

d) branched tracheae

e) hemolymph

b

114

Which of the following are the only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart?

a) amphibians

b) birds

c) fishes

d) mammals

e) reptiles

c

115

Which of the following would be described as a portal system?

a) an area connecting arterioles to venules

b) a series of vessels that returns blood to the heart in an animal with an open circulatory system

c) a space within or between organs where blood is allowed to pool

d) a slightly muscular vessel that has minimal pumping action in an organism with no heart

e) a vessel or vessels connecting two capillary beds

e

116

What is the reason that fluid is forced from the bloodstream to the surrounding tissues at the arteriole end of systemic capillaries?

a) The osmotic pressure of the interstitial fluid is greater than that of the blood.

b) The hydrostatic pressure of the blood is less than that of the interstitial fluid.

c) The hydrostatic pressure of the blood is greater than the osmotic pressure of the blood.

d) The osmotic pressure of the interstitial fluid is greater than the hydrostatic pressure of the blood.

e) The osmotic pressure of the blood is greater than the hydrostatic pressure of the interstitial fluid

c

117

Which of these are involved in the early stages of blood clotting?

a) low-density lipoproteins

b) immunoglobulins

c) erythropoietin

d) epinephrine

e) platelets

e

118

Which of the following occurs with the exhalation of air from human lungs?

a) The volume of the thoracic cavity decreases.

b) The residual volume of the lungs decreases.

c) The diaphragm contracts.

d) The epiglottis closes.

e) The rib cage expands.

a

119

The blood level of which gas is most important in controlling human respiration rate?

a) nitric acid

b) nitrogen

c) oxygen

d) carbon dioxide

e) carbon monoxide

d

120

Which of the following is a characteristic of both hemoglobin and hemocyanin?

a) found within blood cells

b) red in color

c) contains the element iron as an oxygen-binding component

d) transports oxygen

e) occurs in mammals

d

121

How is most of the carbon dioxide transported by the blood in humans?

a) bicarbonate ions in the plasma

b) CO2 attached to hemoglobin

c) carbonic acid in the erythrocytes

d) CO2 dissolved in the plasma

e) bicarbonate attached to hemoglobin

a

122

A bacterium entering the body through a small cut in the skin will do which of the following?

a) inactivate the erythrocytes

b) stimulate apoptosis of nearby body cells

c) stimulate release of interferons

d) stimulate natural killer cell activity

e) activate a group of proteins called complement

e

123

What are antigens?

a) proteins found in the blood that cause foreign blood cells to clump

b) proteins embedded in B cell membranes

c) proteins that consist of two light and two heavy polypeptide chains

d) foreign molecules that trigger the generation of antibodies

e) proteins released during an inflammatory response

d

124

Clonal selection implies that

a) brothers and sisters have similar immune responses.

b) antigens increase mitosis in specific lymphocytes.

c) only certain cells can produce interferon.

d) a B cell has multiple types of antigen receptors.

e) the body selects which antigens it will respond to.

b

125

Which of the following differentiates T cells and B cells?

a) T cells but not B cells are stimulated to increase the rate of their cell cycles.

b) Only B cells are produced from stem cells of the bone marrow.

c) T cells but not B cells can directly attack and destroy invading pathogens.

d) T cells but not B cells have surface markers.

e) Only B cells take part in cell-mediated immunity.

c

126

The MHC is important in a T cell's ability to

a) distinguish self from nonself.

b) recognize specific parasitic pathogens.

c) identify specific bacterial pathogens.

d) identify specific viruses.

e) recognize differences among types of cancer.

a

127

In which of the following situations will helper T cells be activated?

a) when an antigen is displayed by a dendritic cell

b) when a cytotoxic T cell releases cytokines

c) when natural killer (NK) cells come in contact with a tumor cell

d) in the bone marrow during the self-tolerance test

e) when B cells respond to T-independent antigens

a

128

An immunoglobulin (Ig) molecule, of whatever class, has regions symbolized as C or V, H or L. A light chain has which of these regions?

a) one C and one V region

b) three C and one V region

c) one H and one L region

d) three H and one L region

e) two C and two V regions

a

129

Which of the following is the last line of defense against an extracellular pathogen?

a) lysozyme production

b) phagocytosis by neutrophils

c) antibody production by plasma cells

d) histamine release by basophils

e) lysis by natural killer cells

c

130

Which cell type interacts with both the humoral and cell-mediated immune pathways?

a) plasma cells

b) cytotoxic T cells

c) natural killer cells

d) CD8 cells

e) helper T cells

e

131

What is the primary function of humoral immunity?

a) It primarily defends against fungi and protozoa.

b) It is responsible for transplant tissue rejection.

c) It protects the body against cells that become cancerous.

d) It produces antibodies that circulate in body fluids.

e) It primarily defends against bacteria and viruses that have already infected cells.

d

132

A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob),even though Jane has previously given blood for one of Bob's needed transfusions. Which of the following might account for this?

a) Jane's blood type is a match to Bob's but her MHC proteins are not.

b) A blood type match is less stringent than a match required for transplant because blood is more tolerant of change.

c) For each gene, there is only one blood allele but many tissue alleles.

d) Jane's class II genes are not expressed in bone marrow.

e) Bob's immune response has been made inadequate before he receives the transplant.

a

133

Organisms categorized as osmoconformers are most likely

a) found in fresh water lakes and streams.

b) marine.

c) amphibious.

d) found in arid terrestrial environments.

e) found in terrestrial environments with adequate moisture

b

134

Materials are returned to the blood from the filtrate by which of the following processes?

a) filtration

b) ultrafiltration

c) selective reabsorption

d) secretion

e) active transport

c

135

What substance is secreted by the proximal-tubule cells and prevents the pH of urine from becoming too acidic?

a) bicarbonate

b) salt

c) glucose

d) ammonia

e) NaOH

d

136

Which of the following processes of osmoregulation by the kidney is the least selective?

a) salt pumping to control osmolarity

b) H+ pumping to control pH

c) reabsorption

d) filtration

e) secretion

d

137

Which of the following statements about hormones is incorrect?

a) They are produced by endocrine glands.

b) They are modified amino acids, peptides, or steroid molecules.

c) They are carried by the circulatory system.

d) They are used to communicate between different organisms.

e) They elicit specific biological responses from target cells.

d

138

Which of the following is a local regulator responsible for activating an enzyme that relaxes smooth muscle cells?

a) nitric oxide

b) prostaglandin F

c) epinephrine

d) A and B only

e) A, B, and C

a

139

Which of the following examples is incorrectly paired with its class?

a) cytokines-local regulator

b) estrogen-steroid hormone

c) prostaglandin-peptide hormone

d) ecdysone-steroid hormone

e) neurotransmitter-local regulator

c

140

A cell that contains proteins enabling a hormone to selectively bind to its plasma membrane is called a(n)

a) secretory cell.

b) plasma cell.

c) endocrine cell.

d) target cell.

e) regulatory cell

d

141

Which of the following statements about hormones that promote homeostasis is incorrect?

a) A stimulus causes an endocrine cell to secrete a particular hormone.

b) The hormone travels in the bloodstream to target cells.

c) Specific receptors bind with the hormone.

d) Signal transduction brings about a response in the target cell.

e) This response feeds back to promote the release of more hormone

e

142

The hypothalamus controls the anterior pituitary by means of

a) releasing hormones.

b) second messengers.

c) third messengers.

d) antibodies.

e) cytokines.

a

143

Which combination of hormones helps a mother to produce milk and nurse her baby?

a) prolactin and calcitonin

b) oxytocin and prolactin

c) follicle-stimulating hormone and luteinizing hormone

d) luteinizing hormone and oxytocin

e) oxytocin, prolactin, and luteinizing hormone

b

144

Iodine is added to commercially-prepared table salt to help prevent deficiencies of this essential mineral. Which gland(s) require(s) iodine to function properly?

a) parathyroids

b) adrenal

c) thyroid

d) pancreas

e) ovaries and testes

c

145

Which of the following glands shows both endocrine and exocrine activity?

a) pituitary

b) parathyroid

c) salivary

d) pancreas

e) adrenal

d

146

Which of the following are synthesized from the amino acid tyrosine?

a) epinephrine

b) catecholamines

c) thyroxin

d) A and B only

e) A, B, and C

e

147

Which of the following glands is controlled directly by the hypothalamus or central nervous system but not the anterior pituitary?

a) ovary

b) adrenal medulla

c) adrenal cortex

d) testis

e) thyroid

b

148

Which of the following is a steroid hormone that triggers molting in arthropods?

a) ecdysone

b) glucagon

c) thyroxine

d) oxytocin

e) growth hormone

a

149

Which of the following is secreted by the pancreas?

a) ecdysone

b) glucagon

c) thyroxine

d) oxytocin

e) growth hormone

b

150

Testosterone is an example of

a) an androgen.

b) an estrogen.

c) a progestin.

d) a catecholamine.

e) melatonin.

a

151

Estradiol is an example of

a) an androgen.

b) an estrogen.

c) a progestin.

d) a catecholamine.

e) melatonin

b

152

Which of the following is secreted by the pineal gland?

a) androgens

b) estrogens

c) progestins

d) catecholamines

e) melatonin

e

153

Sexual reproduction

a) allows animals to conserve resources and reproduce only during optimal conditions.

b) can produce diverse phenotypes that may enhance survival of a population in a changing environment.

c) yields more numerous offspring more rapidly than is possible with asexual reproduction.

d) enables males and females to remain isolated from each other while rapidly colonizing habitats.

e) guarantees that both parents will provide care for each offspring.

b

154

Evidence that includes

a) the requirement for male-like behaviors in some females before their partners will ovulate.

b) the development and then regression of testes prior to sexual maturation.

c) the observation that all of the offspring are haploid.

d) dependence on favorable weather conditions for ovulation to occur.

e) the persistence of a vestigial penis among some of the females.

a

155

Which statement is false concerning reproduction in invertebrate animals?

a) Separate sexes are not observed among any invertebrates.

b) Some have both sexes within one individual organism.

c) Some utilize external fertilization.

d) Some utilize internal fertilization.

e) None of the invertebrates have structures that store sperm.

e

156

A cloaca is an anatomical structure found in many nonmammalian vertebrates, which functions as

a) a specialized sperm-transfer device produced by males.

b) a common exit for the digestive, excretory, and reproductive systems.

c) a region bordered by the labia minora and clitoris in females.

d) a source of nutrients for developing sperm in the testes.

e) a gland that secretes mucus to lubricate the vaginal opening.

b

157

An oocyte released from a human ovary enters the oviduct as a result of

a) the beating action of the flagellum on the oocyte.

b) the force of the follicular ejection directing the oocyte into the oviduct.

c) the wavelike beating of cilia lining the oviduct.

d) movement of the oocyte through the pulsing uterus into the oviduct.

e) Peristaltic contraction of ovarian muscles.

c

158

The junction of the upper vagina and the uterus is called the

a) fallopian tube.

b) clitoris.

c) oviduct.

d) labia majora.

e) cervix.

e

159

In humans, the follicular cells that remain behind in the ovary following ovulation become

a) ovarian endometrium shed at the time of menses.

b) a steroid-hormone synthesizing structure called the corpus luteum.

c) the thickened portion of the uterine wall.

d) swept into the fallopian tube.

e) the placenta, which secretes cervical mucus.

b

160

The male and female structures that consist mostly of erectile tissue include

a) penis and clitoris.

b) vas deferens and oviduct.

c) testes and ovaries.

d) seminiferous tubules and hymen.

e) prostate and ovaries.

a

161

Testosterone is synthesized primarily by the

a) sperm cells.

b) hypothalamus.

c) Leydig cells.

d) anterior pituitary gland.

e) seminiferous tubules.

c

162

Sperm cells are stored within human males in the

a) urethra.

b) prostate.

c) epididymis.

d) seminal vesicles.

e) bulbourethral gland

c

163

At the time of fertilization, the complete maturation of each oogonium has resulted in

a) one secondary oocyte.

b) two primary oocytes.

c) four secondary oocytes.

d) four primary oocytes.

e) four zygotes.

a

164

A male's "primary" sex characteristics include

a) deepening of the voice at puberty.

b) embryonic differentiation of the seminal vesicles.

c) growth of skeletal muscle.

d) elongation of the skeleton prior to puberty.

e) onset of growth of facial hair at puberty

b

165

The primary difference between estrous and menstrual cycles is that

a) the endometrium shed by the uterus during the estrous cycle is reabsorbed but the shed endometrium is excreted from the body during the menstrual cycle.

b) behavioral changes during estrous cycles are much less apparent than those of menstrual cycles.

c) season and climate have less pronounced effects on estrous cycle than they do on menstrual cycles.

d) copulation normally occurs across the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation.

e) most estrous cycle are of much longer duration compared to menstrual cycles.

a

166

The breakdown and discharge of the soft uterine tissues that occurs if no egg is fertilized is called

a) menstruation.

b) lactation.

c) fertilization.

d) menopause.

e) ovulation.

a

167

The hormone progesterone is produced

a) in the pituitary and acts directly on the ovary.

b) in the uterus and acts directly on the pituitary.

c) in the ovary and acts directly on the uterus.

d) in the pituitary and acts directly on the uterus.

e) in the uterus and acts directly on the pituitary

c

168

Menopause is caused by

a) reduced synthesis of ovarian steroids despite high levels of gonadotropin hormones.

b) a decline in production of the gonadotropin hormones by the anterior pituitary gland.

c) wearing away of the uterine endometrium.

d) an increase in the blood supply to the ovaries.

e) a halt in the synthesis of gonadotropin-releasing hormone by the brain.

a

169

For normal human fertilization to occur,

a) many ova must be released.

b) the uterus must be enlarged.

c) only one sperm need penetrate one egg.

d) secretion of pituitary FSH and LH must decrease.

e) the secondary oocyte must implant in the uterus

c

170

Fertilization of human eggs usually takes place in the

a) ovary.

b) uterus.

c) vagina.

d) oviduct.

e) cervix.

d

171

This embryonic hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy:

a) luteinizing hormone (LH)

b) follicle-stimulating hormone (FSH)

c) progesterone

d) human chorionic gonadotropin (HCG)

e) gonadotropin-releasing hormone (GnRH)

d

172

Among these contraception methods, which has the highest risk of accidental pregnancy?

a) diaphragm

b) condom

c) coitus interruptus

d) vasectomy

e) rhythm method

c

173

The proposal that a human sperm contained a miniature human being is consistent with the now-discredited theory of development known as

a) epigenesis.

b) preformation.

c) cell differentiation.

d) morphogenesis.

e) cell theory.

b

174

As an embryo develops, new cells are produced as the result of

a) differentiation.

b) preformation.

c) cell division.

d) morphogenesis.

e) epigenesis.

c

175

Fertilization of an egg without activation is most like

a) placing the key in the ignition of a car but not starting the engine.

b) resting during halftime of a basketball game.

c) preparing a pie from scratch and baking it in the oven.

d) walking to the cafeteria and eating lunch.

e) dropping a rock off a cliff and watching it land in the valley below

a

176

Contact of an egg with signal molecules on sperm causes the egg to undergo a brief

a) mitosis.

b) membrane depolarization.

c) apoptosis.

d) vitellogenesis.

e) the acrosomal reaction

b

177

During fertilization, the acrosomal contents

a) block polyspermy.

b) help propel more sperm toward the egg.

c) digest the protective coat on the surface of the egg.

d) nourish the mitochondria of the sperm.

e) trigger the completion of meiosis by the sperm.

c

178

The vitelline layer of the sea urchin egg

a) is outside of the fertilization membrane.

b) releases calcium, which initiates the cortical reaction.

c) has receptor molecules that are specific for binding acrosomal proteins.

d) is first visible only when organogenesis is nearly completed.

e) is a mesh of proteins crossing through the cytosol of the egg.

c

179

The cortical reaction functions directly in the

a) formation of a fertilization envelope.

b) production of a fast block to polyspermy.

c) release of hydrolytic enzymes from the sperm cell.

d) generation of a nerve-like impulse by the egg cell.

e) fusion of egg and sperm nuclei.

a

180

The "slow block" to polyspermy is due to

a) a transient voltage change across the membrane.

b) the consumption of yolk protein.

c) the jelly coat blocking sperm penetration.

d) formation of the fertilization envelope.

e) inactivation of the sperm acrosome.

d

181

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

a) acrosomal reaction would be blocked.

b) fusion of sperm and egg nuclei would be blocked.

c) fast block to polyspermy would not occur.

d) fertilization envelope would not be formed.

e) zygote would not contain maternal and paternal chromosomes.

d

182

In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the

a) acrosomal reaction.

b) completion of spermatogenesis.

c) initial cleavage.

d) activation of the egg.

e) completion of gastrulation.

c

183

In mammalian eggs, the receptors for sperm are found in the

a) fertilization membrane.

b) zona pellucida.

c) cytosol of the egg.

d) nucleus of the egg.

e) mitochondria of the egg.

b

184

Compared to sea urchin eggs, those of mammals

a) complete the fertilization process more rapidly.

b) have not already completed meiosis at the time of ovulation.

c) have a more distinct animal pole.

d) have a more distinct vegetal pole.

e) have no requirement for the cortical reaction.

b

185

As cleavage continues during frog development, the size of the blastomeres

a) increases as the number of the blastomeres decreases.

b) increases as the number of the blastomeres increases.

c) decreases as the number of the blastomeres increases.

d) decreases as the number of the blastomeres decreases.

e) increases as the number of the blastomeres stays the same.

c

186

The vegetal pole of the zygote differs from the animal pole in that

a) the vegetal pole has a higher concentration of yolk.

b) the blastomeres originate only in the vegetal pole.

c) the posterior end of the embryo forms at the vegetal pole.

d) the vegetal pole cells undergo mitosis but not cytokinesis.

e) the polar bodies bud from this region.

a

187

The small portion of the embryo that will become its dorsal side develops from the

a) morula.

b) primitive streak.

c) archenteron.

d) gray crescent.

e) blastocoel.

d

188

The yolk of the frog egg

a) prevents gastrulation.

b) is concentrated at the animal pole.

c) is homogeneously arranged in the egg.

d) impedes the formation of a primitive streak.

e) supports the higher rate of cleavage at the animal pole compared to the vegetal pole.

e

189

An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak must be that of

a) an insect.

b) a fish.

c) an amphibian.

d) a bird.

e) a sea urchin.

d

190

Meroblastic cleavage occurs in

a) sea urchins, but not humans or birds.

b) humans, but not sea urchins or birds.

c) birds, but not sea urchins or humans.

d) both sea urchins and birds, but not humans.

e) both humans and birds, but not sea urchins.

c

191

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is

a) endoderm ectoderm  mesoderm.

b) mesoderm  endoderm  ectoderm.

c) ectoderm   mesoderm   endoderm.

d) ectoderm  endoderm  mesoderm.

e) endoderm  mesoderm  ectoderm.

c

192

If gastrulation was blocked by an environmental toxin, then

a) cleavage would not occur in the zygote.

b) embryonic germ layers would not form.

c) fertilization would be blocked.

d) the blastula would not be formed.

e) the blastopore would form above the gray crescent in the animal pole.

b

193

The archenteron of the developing frog eventually develops into the

a) reproductive organs.

b) the blastocoel.

c) heart and lungs.

d) digestive tract.

e) brain and spinal cord.

d

194

Although it contributes no cells to the embryo, this structure guides the formation of the primitive streak:

a) endoderm

b) mesoderm

c) ectoderm

d) neural crest

e) hypoblast

e

195

Uterine implantation due to enzymatic digestion of the endometrium is initiated by

a) the inner cell mass.

b) the endoderm.

c) the chorion.

d) the mesoderm.

e) the trophoblast.

e

196

In placental mammals, the yolk sac

a) transfers nutrients from the yolk to the embryo.

b) differentiates into the placenta.

c) becomes a fluid-filled sac that surrounds and protects the embryo.

d) produces blood cells that then migrate into the embryo.

e) stores waste products from the embryo until the placenta develops.

d

197

Gases are exchanged in a mammalian embryo in the

a) amnion.

b) hypoblast.

c) chorion.

d) trophoblast.

e) yolk sac.

c

198

Which of the following is (are) characteristic of a simple nervous system?

a) a nerve net such as is found in cnidarians

b) nerve cell ganglia

c) having electrical impulses traveling in both directions

d) both A and C

e) A, B, and C

d

199

Which of the following is associated with the evolution of a central nervous system?

a) a complete gut

b) bilateral symmetry

c) radial symmetry

d) a closed circulatory system

e) excitable membranes

b

200

An organism that lacks integration centers

a) cannot receive stimuli.

b) will not have a nervous system.

c) will not be able to interpret stimuli.

d) can be expected to lack myelinated neurons.

c

201

The blood-brain barrier

a) is formed by tight junctions.

b) is formed by oligodendrocytes.

c) tightly regulates the intracellular environment of the CNS.

d) uses chemical signals to communicate with the spinal cord.

e) provides support to the brain tissue.

a

202

Cranial nerves originate in the brain. They belong to which system?

a) central nervous system

b) peripheral nervous system

c) autonomic nervous system

d) parasympathetic nervous system

e) sympathetic nervous system

a

203

Which area of the brain is most intimately associated with the unconscious control of respiration and circulation?

a) thalamus

b) cerebellum

c) medulla

d) corpus callosum

e) cerebrum

c

204

Which of the following produces hormones that are secreted by the pituitary gland?

a) cerebrum

b) cerebellum

c) thalamus

d) hypothalamus

e) medulla oblongata

d

205

Which of the following coordinates muscle actions?

a) cerebrum

b) cerebellum

c) thalamus

d) hypothalamus

e) medulla oblongata

b

206

Which of the following regulates body temperature?

a) cerebrum

b) cerebellum

c) thalamus

d) hypothalamus

e) medulla oblongata

d

207

Which of the following contains regulatory centers for the respiratory and circulatory systems?

a) cerebrum

b) cerebellum

c) thalamus

d) hypothalamus

e) medulla oblongata

e

208

Which of the following contains regions that help regulate hunger and thirst?

a) cerebrum

b) cerebellum

c) thalamus

d) hypothalamus

e) medulla oblongata

d

209

Which processes in animals are regulated by circadian rhythms?

a) sleep cycles

b) hormone release

c) sex drive

d) A and B only

e) A, B, and C

e

210

What do Wernicke's and Broca's regions of the brain affect?

a) olfaction

b) vision

c) speech

d) memory

e) hearing

c

211

If you were writing an essay, which part of the brain would be most active?

a) temporal and frontal lobes

b) parietal lobe

c) Broca's area

d) Wernicke's area

e) occipital lobe

a

212

Short-term memory information processing usually causes changes in the

a) brainstem.

b) medulla.

c) hypothalamus.

d) hippocampus.

e) cranial nerves

d

213

Wakefulness is regulated by the reticular formation, which is present in the

a) basal nuclei.

b) cerebral cortex.

c) brainstem.

d) limbic system.

e) spinal cord.

c

214

Which of the following structures or regions is incorrectly paired with its function?

a) limbic system - motor control of speech

b) medulla oblongata - homeostatic control

c) cerebellum - coordination of movement and balance

d) corpus callosum - communication between the left and right cerebral cortices

e) hypothalamus - regulation of temperature, hunger, and thirst

a

215

What is the neocortex?

a) a primitive brain region that is common to reptiles and mammals

b) a region deep in the cortex that is associated with the formation of emotional memories

c) a central part of the cortex that receives olfactory information

d) an additional outer layer of neurons in the cerebral cortex that is unique to mammals

e) an association area of the frontal lobe that is involved in higher cognitive functions

d

216

What is a genome?

a) The complete complement of an organism's genes

b) A specific set of polypeptides within each cell

c) A specialized polymer of four different kinds of monomers

d) A specific segment of DNA that is found within a prokaryotic chromosome

e) An ordered display of chromosomes arranged from largest to smallest

a

217

Asexual reproduction results in identical offspring unless which of the following occurs?

a) Natural selection

b) Cloning

c) Crossing over

d) Mutation

e) Environmental change

d

218

A gene's location along a chromosome is known as which of the following?

a) Allele

b) Sequence

c) Locus

d) Variant

e) Trait

c

219

What is a karyotype?

a) The set of unique physical characteristics that define an individual

b) The collection of all the mutations present within the genome of an individual

c) The combination of chromosomes found in a gamete

d) A system of classifying cell nuclei

e) A display of every pair of homologous chromosomes within a cell, organized according to size and shape

e

220

The human X and Y chromosomes

a) are both present in every somatic cell of males and females alike.

b) are of approximately equal size and number of genes.

c) are almost entirely homologous, despite their different names.

d) include genes that determine an individual's sex.

e) include only genes that govern sex determination.

d

221

In animals, meiosis results in gametes, and fertilization results in

a) spores.

b) gametophytes.

c) zygotes.

d) sporophytes.

e) clones.

c

222

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?

a) It must be human.

b) It must be a primate.

c) It must be an animal.

d) It must be sexually reproducing.

e) Its gametes must have 23 chromosomes.

e

223

Which of the following occurs in meiosis but not in mitosis?

a) Chromosome replication

b) Synapsis of chromosomes

c) Production of daughter cells

d) Alignment of chromosomes at the equator

e) Condensation of chromatin

b

224

A tetrad includes which of the following sets of DNA strands?

a) Two single-stranded chromosomes that have synapsed

b) Two sets of sister chromatids that have synapsed

c) Four sets of sister chromatids

d) Four sets of unique chromosomes

e) Eight sets of sister chromatids

b

225

Pea plants were particularly well suited for use in Mendel's breeding experiments for all of the following reasons except that

a) peas show easily observed variations in a number of characters, such as pea shape and flower color.

b) it is possible to control matings between different pea plants.

c) it is possible to obtain large numbers of progeny from any given cross.

d) peas have an unusually long generation time.

e) many of the observable characters that vary in pea plants are controlled by single genes

d

226

What is the difference between a monohybrid cross and a dihybrid cross?

a) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents.

b) A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny.

c) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only one.

d) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations.

e) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.

c

227

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

a) There is considerable genetic variation in garden peas.

b) Traits are inherited in discrete units, and are not the results of "blending."

c) Recessive genes occur more frequently in the F1 than do dominant ones.

d) Genes are composed of DNA.

e) An organism that is homozygous for many recessive traits is at a disadvantage

b

228

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

a) 4

b) 8

c) 16

d) 32

e) 64

b

229

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phasesof cell division?

a) Prophase I of meiosis

b) Prophase II of meiosis

c) Metaphase I of meiosis

d) Anaphase I of meiosis

e) Anaphase of mitosis

d

230

Mendel's second law of independent assortment has its basis in which of the following events of meiosis I?

a) Synapsis of homologous chromosomes

b) Crossing over

c) Alignment of tetrads at the equator

d) Separation of homologs at anaphase

e) Separation of cells at telophase

c

231

In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?

a) 1/4

b) 1/8

c) 1/16

d) 1/32

e) 1/64

e

232

Given the parents AABBCc × AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?

a) 1/4

b) 1/8

c) 3/4

d) 3/8

e) 1

c

233

Which describes the ability of a single gene to have multiple phenotypic effects?

a) Incomplete dominance

b) Multiple alleles

c) Pleiotropy

d) Epistasis

c

234

Which describes the ABO blood group system?

a) Incomplete dominance

b) Multiple alleles

c) Pleiotropy

d) Epistasis

b

235

People with sickle-cell trait

a) are heterozygous for the sickle-cell allele.

b) are usually healthy.

c) have increased resistance to malaria.

d) produce normal and abnormal hemoglobin.

e) All of the above

e

236

When a disease is said to have a multifactorial basis, it means that

a) both genetic and environmental factors contribute to the disease.

b) it is caused by a gene with a large number of alleles.

c) it affects a large number of people.

d) it has many different symptoms.

e) it tends to skip a generation.

a

237

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

a) It revealed new and unanticipated features of Mendel's pea plant varieties.

b) It allowed the study of meiosis and mitosis, revealing parallels between behaviors of genes and chromosomes.

c) It allowed scientists to see the DNA present within chromosomes.

d) It led to the discovery of mitochondria.

e) It showed genes functioning to direct the formation of enzymes.

b

238

What is the chromosomal system for sex determination in birds?

a) Haploid-diploid

b) X-0

c) X-X

d) X-Y

e) Z-W

e

239

What is the chromosomal system of sex determination in most species of ants and bees?

a) Haploid-diploid

b) X-0

c) X-X

d) X-Y

e) Z-W

a

240

SRY is best described in which of the following ways?

a) A gene region present on the Y chromosome that triggers male development

b) A gene present on the X chromosome that triggers female development

c) An autosomal gene that is required for the expression of genes on the Y chromosome

d) An autosomal gene that is required for the expression of genes on the X chromosome

e) Required for development, and males or females lacking the gene do not survive past early childhood

a

241

Calico cats are female because

a) a male inherits only one of the two X-linked genes controlling hair color.

b) the males die during embryonic development.

c) the Y chromosome has a gene blocking orange coloration.

d) only females can have Barr bodies.

e) multiple crossovers on the Y chromosome prevent orange pigment production

a

242

New combinations of linked genes are due to which of the following?

a) Nondisjunction

b) Crossing over

c) Independent assortment

d) Mixing of sperm and egg

e) Deletions

b

243

A cell that has 2n + 1 chromosomes is

a) trisomic.

b) monosomic.

c) euploid.

d) polyploid.

e) triploid.

a

244

Women with Turner syndrome have a genotype characterized as which of the following?

a) aabb

b) Mental retardation and short arms

c) A karyotype of 45, X

d) A karyotype of 47, XXX

e) A deletion of the Y chromosome

c

245

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

a) Frequency of new meiosis

b) Average of the ages of mother and father

c) Age of the mother

d) Age of the father

e) Exposure of pregnant women to environmental pollutants

c

246

What does transformation involve in bacteria?

a) the creation of a strand of DNA from an RNA molecule

b) the creation of a strand of RNA from a DNA molecule

c) the infection of cells by a phage DNA molecule

d) the type of semiconservative replication shown by DNA

e) assimilation of external DNA into a cell

e

247

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

a) DNA contains sulfur, whereas protein does not.

b) DNA contains phosphorus, but protein does not.

c) DNA contains nitrogen, whereas protein does not.

d) DNA contains purines, whereas protein includes pyrimidines.

e) RNA includes ribose, while DNA includes deoxyribose sugars.

b

248

Which of the following investigators was/were responsible for the following discovery? Phage with labeled proteins or DNA was allowed to infect bacteria. It was shown that the DNA, but not the protein, entered the bacterial cells, and was therefore concluded to be the genetic material.

a) Frederick Griffith

b) Alfred Hershey and Martha Chase

c) Oswald Avery, Maclyn McCarty, and Colin MacLeod

d) Erwin Chargaff

e) Matthew Meselson and Franklin Stahl

e

249

When T2 phages infect bacteria and make more viruses in the presence of radioactive sulfur, what is the result?

a) The viral DNA will be radioactive.

b) The viral proteins will be radioactive.

c) The bacterial DNA will be radioactive.

d) both A and B

e) both A and C

b

250

Why does the DNA double helix have a uniform diameter?

a) Purines pair with pyrimidines.

b) C nucleotides pair with A nucleotides.

c) Deoxyribose sugars bind with ribose sugars.

d) Nucleotides bind with nucleosides.

e) Nucleotides bind with nucleoside triphosphates

a

251

What kind of chemical bond is found between paired bases of the DNA double helix?

a) hydrogen

b) ionic

c) covalent

d) sulfhydryl

e) phosphate

a

252

Replication in prokaryotes differs from replication in eukaryotes for which of these reasons?

a) The prokaryotic chromosome has histones, whereas eukaryotic chromosomes do not.

b) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

c) The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.

d) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.

e) Prokaryotes have telomeres, and eukaryotes do not.

b

253

What is the function of DNA polymerase III?

a) to unwind the DNA helix during replication

b) to seal together the broken ends of DNA strands

c) to add nucleotides to the end of a growing DNA strand

d) to degrade damaged DNA molecules

e) to rejoin the two DNA strands (one new and one old) after replication

c

254

Which of the following covalently connects segments of DNA?

a) helicase

b) DNA polymerase III

c) ligase

d) DNA polymerase I

e) primase

c

255

Which of the following synthesizes short segments of RNA?

a) helicase

b) DNA polymerase III

c) ligase

d) DNA polymerase I

e) primase

e

256

The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that

a) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.

b) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups.

c) ATP contains three high-energy bonds; the nucleoside triphosphates have two.

d) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells.

e) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP.

a

257

The leading and the lagging strands differ in that

a) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

b) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.

c) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together.

d) the leading strand is synthesized at twice the rate of the lagging strand.

a

258

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

a) synthesize RNA nucleotides to make a primer

b) catalyze the lengthening of telomeres

c) join Okazaki fragments together

d) unwind the parental double helix

e) stabilize the unwound parental DNA

d

259

Which of the following help to hold the DNA strands apart while they are being replicated?

a) primase

b) ligase

c) DNA polymerase

d) single-strand binding proteins

e) exonuclease

d

260

Why do histones bind tightly to DNA?

a) Histones are positively charged, and DNA is negatively charged.

b) Histones are negatively charged, and DNA is positively charged.

c) Both histones and DNA are strongly hydrophobic.

d) Histones are covalently linked to the DNA.

e) Histones are highly hydrophobic, and DNA is hydrophilic.

a

261

Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because

a) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

b) enzymes are made of DNA, and affected individuals lack DNA polymerase.

c) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA.

d) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors.

e) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.

a

262

The nitrogenous base adenine is found in all members of which group?

a) proteins, triglycerides, and testosterone

b) proteins, ATP, and DNA

c) ATP, RNA, and DNA

d) alpha glucose, ATP, and DNA

e) proteins, carbohydrates, and ATP

c

263

The "universal" genetic code is now known to have exceptions. Evidence for this could be found if which of the following is true?

a) If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only).

b) If one stop codon, such as UGA, is found to have a different effect on translation than another stop codon, such as UAA.

c) If prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide.

d) If several codons are found to translate to the same amino acid, such as serine.

e) If a single mRNA molecule is found to translate to more than one polypeptide when there are two or more AUG sites

a

264

In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?

a) ligase

b) RNA polymerase I

c) RNA polymerase II

d) RNA polymerase III

e) primase

c

265

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

a) the protein product of the promoter

b) start and stop codons

c) ribosomes and tRNA

d) several transcription factors (TFs)

e) aminoacyl synthetase

d

266

Which of the following help(s) to stabilize mRNA by inhibiting its degradation?

a) TATA box

b) spliceosomes

c) 5' cap and poly (A) tail

d) introns

e) RNA polymerase

c

267

What is a ribozyme?

a) an enzyme that uses RNA as a substrate

b) an RNA with enzymatic activity

c) an enzyme that catalyzes the association between the large and small ribosomal subunits

d) an enzyme that synthesizes RNA as part of the transcription process

e) an enzyme that synthesizes RNA primers during DNA replication

b

268

What are the coding segments of a stretch of eukaryotic DNA called?

a) introns

b) exons

c) codons

d) replicons

e) transposons

b

269

During splicing, which molecular component of the spliceosome catalyzes the excision reaction?

a) protein

b) DNA

c) RNA

d) lipid

e) sugar

c

270

Alternative RNA splicing

a) is a mechanism for increasing the rate of transcription.

b) can allow the production of proteins of different sizes from a single mRNA.

c) can allow the production of similar proteins from different RNAs.

d) increases the rate of transcription.

e) is due to the presence or absence of particular snRNPs.

b

271

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?

a) the sequence of the intron that immediately precedes each exon

b) the number of polypeptides making up the functional protein

c) the various domains of the polypeptide product

d) the number of restriction enzyme cutting sites

e) the number of start sites for transcription

c

272

What is the most abundant type of RNA?

a) mRNA

b) tRNA

c) rRNA

d) pre-mRNA

e) hnRNA

c

273

Sickle-cell disease is probably the result of which kind of mutation?

a) point

b) frameshift

c) nonsense

d) nondisjunction

e) both B and D

a

274

A frameshift mutation could result from

a) a base insertion only.

b) a base deletion only.

c) a base substitution only.

d) deletion of three consecutive bases.

e) either an insertion or a deletion of a base.

e

275

Which of the following DNA mutations is the most likely to be damaging to the protein it specifies?

a) a base-pair deletion

b) a codon substitution

c) a substitution in the last base of a codon

d) a codon deletion

e) a point mutation

a

276

The host range of a virus is determined by

a) the proteins on its surface and that of the host.

b) whether its nucleic acid is DNA or RNA.

c) the proteins in the host's cytoplasm.

d) the enzymes produced by the virus before it infects the cell.

e) the enzymes carried by the virus.

a

277

Why are viruses referred to as obligate parasites?

a) They cannot reproduce outside of a host cell.

b) Viral DNA always inserts itself into host DNA.

c) They invariably kill any cell they infect.

d) They can incorporate nucleic acids from other viruses.

e) They must use enzymes encoded by the virus itself.

a

278

Which of the following molecules make up the viral envelope?

a) glycoproteins

b) proteosugars

c) carbopeptides

d) peptidocarbs e) carboproteins

a

279

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of life?

a) re-infection by a closely related herpesvirus of a different strain

b) re-infection by the same herpesvirus strain

c) co-infection with an unrelated virus that causes the same symptoms

d) copies of the herpesvirus genome permanently maintained in host nuclei

e) copies of the herpesvirus genome permanently maintained in host cell cytoplasm

d

280

Which of the following is characteristic of the lytic cycle?

a) Many bacterial cells containing viral DNA are produced.

b) Viral DNA is incorporated into the host genome.

c) The viral genome replicates without destroying the host.

d) A large number of phages is released at a time.

e) The virus-host relationship usually lasts for generations.

d

281

Which of the following terms describes bacteriophage DNA that has become integrated into the host cell chromosome?

a) intemperate bacteriophages

b) transposons

c) prophages

d) T-even phages

e) plasmids

c

282

Which of the following statements describes the lysogenic cycle of lambda () phage?

a) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses.

b) Most of the prophage genes are activated by the product of a particular prophage gene.

c) The phage genome replicates along with the host genome.

d) Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic.

e) The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA.

d

283

Why do RNA viruses appear to have higher rates of mutation?

a) RNA nucleotides are more unstable than DNA nucleotides.

b) Replication of their genomes does not involve the proofreading steps of DNA replication.

c) RNA viruses replicate faster.

d) RNA viruses can incorporate a variety of nonstandard bases.

e) RNA viruses are more sensitive to mutagens.

b

284

What is the name given to viruses that are single-stranded RNA that acts as a template for DNA synthesis?

a) retroviruses

b) proviruses

c) viroids

d) bacteriophages

e) lytic phages

a

285

What is the function of reverse transcriptase in retroviruses?

a) It hydrolyzes the host cell's DNA.

b) It uses viral RNA as a template for DNA synthesis.

c) It converts host cell RNA into viral DNA.

d) It translates viral RNA into proteins.

e) It uses viral RNA as a template for making complementary RNA strands.

b

286

What are prions?

a) misfolded versions of normal brain protein

b) tiny molecules of RNA that infect plants

c) viral DNA that has had to attach itself to the host genome

d) viruses that invade bacteria

e) a mobile segment of DNA

a

287

Which of the following is the best predictor of how much damage a virus causes?

a) ability of the infected cell to undergo normal cell division

b) ability of the infected cell to carry on translation

c) whether the infected cell produces viral protein

d) whether the viral mRNA can be transcribed

e) how much toxin the virus produces

a

288

Antiviral drugs that have become useful are usually associated with which of the following properties?

a) ability to remove all viruses from the infected host

b) interference with the viral reproduction

c) prevention of the host from becoming infected

d) removal of viral proteins

e) removal of viral mRNAs

b

289

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?

a) metabolism

b) ribosomes

c) genetic material composed of nucleic acid

d) cell division

e) independent existence

c

290

Emerging viruses arise by

a) mutation of existing viruses.

b) the spread of existing viruses to new host species.

c) the spread of existing viruses more widely within their host species.

d) all of the above

e) none of the above

d

291

Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true?

a) They are gram-negative.

b) They are subject to lysis in hypotonic conditions.

c) They lack a cell membrane as well.

d) They undergo ready fossilization in sedimentary rock.

e) They possess typical prokaryotic flagella.

b

292

Which is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leavethe cell?

a) plasma membrane

b) capsule

c) cell wall

d) nucleoid region

e) pili

a

293

Which statement about bacterial cell walls is false?

a) Bacterial cell walls differ in molecular composition from plant cell walls.

b) Cell walls prevent cells from bursting in hypotonic environments.

c) Cell walls prevent cells from dying in hypertonic conditions.

d) Bacterial cell walls are similar in function to the cell walls of many protists, fungi, and plants.

e) Cell walls provide the cell with a degree of physical protection from the environment.

c

294

Which of these is the most common compound in the cell walls of gram-positive bacteria?

a) cellulose

b) lipopolysaccharide

c) lignin

d) peptidoglycan

e) protein

d

295

The typical prokaryotic flagellum features

a) an internal 9 + 2 pattern of microtubules.

b) an external covering provided by the plasma membrane.

c) a complex "motor" embedded in the cell wall and plasma membrane.

d) a basal body that is similar in structure to the cell's centrioles.

c

296

Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct?

a) Some selective antibiotics can block protein synthesis of bacteria without effects on protein synthesis in the eukaryotic host.

b) Eukaryotes did not evolve from prokaryotes.

c) Translation can occur at the same time as transcription in eukaryotes but not in prokaryotes.

d) Some antibiotics can block the synthesis of peptidoglycan in the walls of bacteria.

e) Prokaryotes are able to use a much greater variety of molecules as food sources than can eukaryotes.

a

297

Which statement about the genomes of prokaryotes is correct?

a) Prokaryotic genomes are diploid throughout most of the cell cycle.

b) Prokaryotic chromosomes are sometimes called plasmids.

c) Prokaryotic cells have multiple chromosomes, "packed" with a relatively large amount of protein.

d) The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleoid region.

e) Prokaryotic genomes are composed of linear DNA (that is, DNA existing in the form of a line with two ends).

e

298

Which of the following requires ATP to function, and permits some species to respond to taxes (plural of taxis)?

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

c

299

Not present in all bacteria, this cell covering enables cells that possess it to resist the defenses of host organisms:

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

e

300

Not present in all bacteria, this structure enables those that possess it to germinate after exposure to harsh conditions,such as boiling:

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

a

301

Which of the following is a structure that permits conjugation to occur?

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

b

302

Which of the following is an important source of endotoxin in gram-negative species?

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

d

303

If this structure connects the cytoplasm of two bacteria, one of these cells may gain new genetic material:

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

b

304

Which of the following contains a copy of the chromosome, along with a small amount of dehydrated cytoplasm, within a tough wall?

a) endospore

b) sex pilus

c) flagellum

d) cell wall

e) capsule

a

305

Cyanobacteria are

a) photoautotrophs.

b) photoheterotrophs.

c) chemoautotrophs.

d) chemoheterotrophs that perform decomposition.

e) parasitic chemoheterotrophs

a

306

Which of the following use light energy to synthesize organic compounds from CO2?

a) photoautotrophs

b) photoheterotrophs

c) chemoautotrophs

d) chemoheterotrophs that perform decomposition

e) parasitic chemoheterotrophs

a

307

Which of the following obtain energy by oxidizing inorganic substances; energy that is used, in part, to fix CO2?

a) photoautotrophs

b) photoheterotrophs

c) chemoautotrophs

d) chemoheterotrophs that perform decomposition

e) parasitic chemoheterotrophs

c

308

Which of the following statements about ecology is incorrect?

a) Ecologists may study populations and communities of organisms.

b) Ecological studies may involve the use of models and computers.

c) Ecology is a discipline that is independent from natural selection and evolutionary history.

d) Ecology spans increasingly comprehensive levels of organization, from individuals to ecosystems.

e) Ecology is the study of the interactions between biotic and abiotic aspects of the environment

c

309

Which of the following levels of organization is arranged in the correct sequence from most to least inclusive?

a) community, ecosystem, individual, population

b) ecosystem, community, population, individual

c) population, ecosystem, individual, community

d) individual, population, community, ecosystem

e) individual, community, population, ecosystem

b

310

Ecology as a discipline directly deals with all of the following levels of biological organization except

a) population.

b) cellular.

c) organismal.

d) ecosystem.

e) community.

b

311

Which statement best contrasts environmentalism with ecology?

a) Ecology is the study of the environment; environmentalism is the study of ecology.

b) Ecology provides scientific understanding of living things and their environment; environmentalism is more about conservation and preservation of life on Earth.

c) Environmentalists are only involved in politics and advocating for protecting nature; ecologists are only involved in scientific investigations of the environment.

d) Ecologists study organisms in environments that have been undisturbed by human activities; environmentalists study the effects of human activities on organisms.

e) Environmentalism is devoted to applied ecological science; ecology is concerned with basic/theoretical ecological science.

b

312

Which of the following are important biotic factors that can affect the structure and organization of biological communities?

a) precipitation, wind

b) nutrient availability, soil pH

c) predation, competition

d) temperature, water

e) light intensity, seasonality

c

313

Which of the following abiotic factors has the greatest influence on the metabolic rates of plants and animals?

a) water

b) wind

c) temperature

d) rocks and soil

e) disturbances

c

314

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the

a) autumn and spring.

b) autumn and winter.

c) spring and summer.

d) summer and winter.

e) summer and autumn.

a

315

Which of the following is responsible for the summer and winter stratification of deep temperate lakes?

a) Water is densest at 4°C.

b) Oxygen is most abundant in deeper waters.

c) Winter ice sinks in the summer.

d) Stratification is caused by a thermocline.

e) Stratification always follows the fall and spring turnovers.

a

316

The main reason polar regions are cooler than the equator is because

a) there is more ice at the poles.

b) sunlight strikes the poles at an lower angle.

c) the poles are farther from the sun.

d) the poles have a thicker atmosphere.

e) the poles are permanently tilted away from the sun.

b

317

Which of the following organisms is the most likely candidate for geographic isolation?

a) sparrow

b) bat

c) squirrel

d) salt-water fish

e) land snail

e

318

Which biome is able to support many large animals despite receiving moderate amounts of rainfall?

a) tropical rain forest

b) temperate forest

c) chaparral

d) taiga

e) savanna

e

319

Tropical grasslands with scattered trees are also known as

a) taigas.

b) tundras.

c) savannas.

d) chaparrals.

e) temperate plains

c

320

Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earth's ancient age?

a) Georges Cuvier

b) Charles Lyell

c) Alfred Wallace

d) Thomas Malthus

e) John Henslow

b

321

Which of these naturalists synthesized a concept of natural selection independently of Darwin?

a) Charles Lyell

b) Gregor Mendel

c) Alfred Wallace

d) John Henslow

e) Thomas Malthus

c

322

Charles Darwin was the first person to propose

a) that evolution occurs.

b) a mechanism for how evolution occurs.

c) that the Earth is older than a few thousand years.

d) a mechanism for evolution that was supported by evidence.

e) a way to use artificial selection as a means of domesticating plants and animals.

d

323

In Darwin's thinking, the more closely related two different organisms are, the

a) more similar their habitats are.

b) less similar their DNA sequences are.

c) more recently they shared a common ancestor.

d) less likely they are to have the same genes in common.

e) more similar they are in size

c

324

Of the following anatomical structures, which is homologous to the wing of a bird?

a) Dorsal fin of a shark

b) Hindlimb of a kangaroo

c) Wing of a butterfly

d) Tail fin of a flying fish

e) Flipper of a cetacean

e

325

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that

a) island forms and mainland forms descended from common ancestors.

b) common environments are inhabited by the same organisms.

c) the islands were originally part of the continent.

d) the island forms and mainland forms are converging.

e) island forms and mainland forms have identical gene pools.

a

326

DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

a) humans and chimpanzees share a relatively recent common ancestor.

b) humans evolved from chimpanzees.

c) chimpanzees evolved from humans.

d) convergent evolution led to the DNA similarities.

e) humans and chimpanzees are not closely related.

a


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