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Principles of

ANIMALPHYSIOLOGYSECOND EDITION

Kelly L. Shoemaker, Ph.D.QU E E N ’ S U N I V E R S I T Y

Alan F. Smith, Ph.D.M E R C E R U N I V E R S I T Y

Tracy Wagner, Ph.D.WA S H BU R N U N I V E R S I T Y

Publisher: Frank RuggirelloAcquisitions Editor: Deirdre EspinozaProject Editor: Marie BeaugureauAssistant Editor: Emily PortwoodDevelopment Manager: Claire AlexanderProduction Manager: Deborah CoganProduction Supervisor: Mary O’ConnellManufacturing Buyer: Stacey WeinbergerMarketing Manager: Gordon LeeCopyeditor: Michael RossaCover Photograph:Tim Flach / Getty Images / Stone Allstock Supplement Cover Designer: 17th Street Studios Main Text Cover Designer: Rokusek Design

ISBN-10: 0-321-50585-9ISBN-13: 978-0-321-50585-9

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Contents Chapter 1 Introduction to Physiological Principles 1

Chapter 2 Chemistry, Biochemistry, and Cell Physiology 12

Chapter 3 Cell Signaling and Endocrine Regulation 25

Chapter 4 Neuron Structure and Function 37

Chapter 5 Cellular Movement and Muscles 53

Chapter 6 Sensory Systems 68

Chapter 7 Functional Orgnaization of Nervous Systems 85

Chapter 8 Circulatory Systems 98

Chapter 9 Respiratory Systems 115

Chapter 10 Ion and Water Balance 131

Chapter 11 Digestion 145

Chapter 12 Locomotion 158

Chapter 13 Thermal Physiology 171

Chapter 14 Reproduction 182

Chapter 1 Introduction to Physiological Principles

Multiple Choice Questions

1) An explosion in physiological research occurred in the 1960s becauseA) there was an increase in the number of physiologists.B) physiologists in one specialty worked only with each other, concentrating their

knowledge.C) physiologists began focusing on local species, rather than trying to study organisms from

many areas.D) all of the above

Answer: DPage Ref: 2

2) The Alpha Helix was an oceanic vessel that was namedA) because it was the first vessel to have helical mobility.B) because it was the first vessel to be able to circle the globe.C) because it had the ability to isolate DNA onboard.D) after the model for DNA structure.


3) Animal physiology is the study ofA) how structures allow animals to function.B) the chemical reactions found in animals.C) the genetic lineage seen in the evolution of animals.D) migratory patterns of animals.

Answer: APage Ref: 4

4) One theme in physiology states that the physiology of an animal is part of its __________,which is based on its __________ and environmental influences.

A) genotype; ancestry B) phenotype; genotypeC) ancestry; phenotype D) phenotype; diet

Answer: BPage Ref: 4

5) Which of the following statements is true about phenotype?A) After an initial development period, phenotype of an organism is static.B) Phenotype is affected by organization at the biochemical level only.C) Altering phenotype allows an organism to change its physiological response.D) Genotype may influence phenotype, but phenotype never affects genotype.

Answer: CPage Ref: 4

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Principles of Animal Physiology, 2e Test Bank

6) The first person to carry out well-designed and careful experiments relating to body functionswas

A) Hippocrates. B) Aristotle. C) Galen D) Ibn al-Nafis.Answer: CPage Ref: 5

7) When Galen tied off the laryngeal nerve of a pig and it stopped squealing, he concluded thatA) the laryngeal nerve generated sound.B) the brain and nerves control the voice.C) the laryngeal nerve allowed perception of pain.D) the laryngeal nerve controlled the pigʹs ability to breathe.


8) One of the contributions of Andreas Vesalius to physiological study wasA) demonstrating that Galenʹs work contained many flaws.B) authoring the first physiological text.C) reviewing the current knowledge of health and disease.D) discovering that the lungs allow the blood to receive oxygen.


9) Scientists studying physiology before the 1700s believed that it was based onA) chemical reactions only.B) physical reactions only.C) either chemical or physical reactions (but not both).D) both chemical and physical reactions.


10) The ʺcell theoryʺ proposed by Schleiden and Schwann statesA) organisms are made of units, or cells.B) organs are joined together to form cells.C) only organisms that contain multiple cells can evolve.D) the cell is the basis of physiology.


11) Per Scholander, one of the first __________ physiologists, looked at diving mechanisms,warm-blooded responses to cold environments, and fish swim bladders.

A) invertebrate B) human C) comparative D) ecologicalAnswer: CPage Ref: 6

12) __________ discovered central pattern generators.A) C. Ladd Prosser B) Knut Schmidt-NielsenC) George Bartholomew D) George Somero


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13) A respiratory physiologist is an example of a/anA) cell and molecular physiologist. B) systems physiologist.C) organismal physiologist. D) ecological physiologist.


14) Physiologists who study the interaction between an organismʹs unique physiology and itsspecies or population are called

A) systems physiologists. B) ecological physiologists.C) integrative physiologists. D) organismal physiologists.


15) One approach, known as __________, says that we can learn about one level of organization bystudying the functions at the level below it.

A) reductionism B) emergenceC) systematics D) bioinformatics


16) A/an __________ physiologist studies how an individual organism alters its physiology inresponse to environmental challenges.

A) developmental B) evolutionaryC) environmental D) organismal


17) An individual who studies veterinary medicine falls into the category of a(n) __________physiologist.

A) medical B) comparative C) systems D) appliedAnswer: DPage Ref: 8

18) Which of the following is an example of how chemical laws affect physiology?A) An organism is able to jump higher based on the attachment point of its muscles to its

skeleton.B) An increase in pressure difference will increase the flow through a system.C) An increase in pH (fewer H+) will change the interaction of bonds holding proteins

together.D) There are no examples because chemical laws have no effect on physiology.


19) Which of the following statements about electrical gradients is correct?A) They can be generated by moving ions across a membrane.B) They are used to drive other processes in organisms.C) Neurons use changes in electrical gradients to send signals.D) all of the above


3


20) Surface area to volume ratio influences thermal physiology such thatA) small animals have a higher surface area to volume ratio, decreasing heat loss.B) small animals have a lower surface area to volume ratio, decreasing heat loss.C) small animals have a higher surface area to volume ratio, increasing heat loss.D) small animals have a lower surface area to volume ratio, increasing heat loss.


21) Max Rubnerʹs work suggesting that the scaling coefficient for metabolic rate should be 2/3 isbased on

A) relationships between surface area and volume.B) relationships between body mass and volume.C) relationships between volume and metabolism.D) relationships between metabolism and activity of the animal.


22) Which of the following statements about conformers and regulators is correct?A) In a conformer, internal conditions mimic external changes.B) In a regulator, internal conditions regulate external changes.C) An organism could be a thermo-conformer and an ionoregulator.D) both A and C


23) Being a conformer is beneficial becauseA) itʹs possible to maintain a stable environment.B) it consumes less energy than being a regulator.C) it allows an organism to live in a wide range of environments that differ from its internal

environment.D) all of the above


24) Maintaining homeostasis relies onA) short-term behavioral changes. B) short-term physiological changes.C) long term strategies. D) all of the above


25) Growing and shedding fur is an example of a physiological change following aA) seasonal cycle. B) circadian rhythm.C) lunar cycle. D) diurnal cycle.


4


26) When maintaining homeostasis, it is important to do all of the following EXCEPTA) detect external conditions.B) control external conditions.C) generate compensatory responses to the changes.D) protect vital areas from damaging changes.

Answer: BPage Ref: 12-13

27) The set point in a feedback loop isA) the point at which the stimulus no longer is required.B) the point at which the (effector) organ or gland starts to change the environment.C) a range of values for a parameter that the body tries to maintain.D) the last step of a series of changes before the body is ʺset.ʺ


28) __________ is/are an example of positive feedback loop control.A) VomitingB) Maintaining internal body temperatureC) Plasma glucose levelsD) Eating when hungry


29) The phenotypic expression of a genotype can be altered byA) developmental processes. B) environmental conditions.C) physiological conditions. D) all of the above

Answer: DPage Ref: 13-14

30) Polyphenism is a type of phenotypic plasticity thatA) can be easily reversed when necessary.B) occurs only when adults are exposed to certain environmental factors.C) is also called developmental plasticity.D) all of the above


31) Acclimatization is a term referring toA) irreversible changes in phenotype due to natural environmental variation.B) irreversible changes in phenotype due to controlled environmental change.C) reversible changes in phenotype due to natural environmental variation.D) reversible changes in phenotype due to controlled environmental change.


5


32) The proximate cause of an organismʹs unique characteristic can be answered byA) studying the animals lineage.B) looking for evolutionary advantages of the characteristic.C) identifying the genes that regulate the characteristic.D) both A and B


33) The term adaptation most commonly refers toA) changes within an individual that are irreversible.B) changes within an individual that are reversible.C) changes within a population seen over time.D) changes within an individual that cannot be inherited.


34) Adaptation can change the genetic composition of a population becauseA) environmental stressors favor survival of certain genotypes.B) individuals possessing favorable genes tend to produce more offspring.C) genes are passed on only if offspring are produced.D) all of the above


35) Genetic drift is most likely to occurA) due to differences in ʺfitnessʺ of individuals.B) in large populations.C) when a large portion of the population is killed, regardless of genetics.D) in ocean populations where genes can drift between individuals.


36) Organisms that are closely related to each other willA) share some features with all other organisms.B) share some features only with organisms from this same group.C) have no features in common with any other organism.D) both A and B


True/False Questions

37) Physiological processes function separately from physical and chemical laws.Answer: FALSEPage Ref: 4

38) Phenotype of an organism is based solely on genotype.Answer: FALSEPage Ref: 4

6


39) Some of the first physiological experiments occurred in the mid-100s.Answer: TRUEPage Ref: 5

40) Most of the experiments before the 20th century were performed on animals in hopes ofgaining knowledge about human physiology.Answer: TRUEPage Ref: 5

41) Emergence says that studying individual parts of a system allows one to clearly predict howthe system as a whole will function.Answer: FALSEPage Ref: 8

42) The research done by a comparative physiologist is done with a (very specific) practical goal inmind.Answer: FALSEPage Ref: 8

43) The mechanical properties of tissue are dependent on the biological molecules from which it ismade.Answer: TRUEPage Ref: 10

44) Surface area to volume ratios remain constant, regardless of body size.Answer: FALSEPage Ref: 11

45) Metabolic rates are proportional to body mass.Answer: FALSEPage Ref: 11

46) Organisms that are capable of homeostasis keep everything in their internal environmentconstant at all times.Answer: FALSEPage Ref: 12

47) Many cyclical physiological changes are triggered by environmental cues.Answer: TRUEPage Ref: 12

48) Positive feedback loops maintain a variable within its set point range.Answer: FALSEPage Ref: 13

49) Water fleas (Daphnia pulex) produce either long or short spiky tails depending on the presenceof predators in their environment. This is an example of polyphenism.Answer: TRUEPage Ref: 14

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50) The terms adaptation and acclimation can always be used interchangeably.Answer: FALSEPage Ref: 15

51) Adaptation is always beneficial to an individual, even if the environmental cause for thechange is no longer present.Answer: FALSEPage Ref: 15

52) Evolution can occur if a population is able to maintain identical genotypes.Answer: FALSEPage Ref: 16

Fill-in-the-Blank Questions

53) Feedback loops maintain the internal environment in an acceptable state, or __________.Answer: homeostasisPage Ref: 4

54) __________ is known as the father of medicine.Answer: HippocratesPage Ref: 4

55) Claude Bernard proposed the concept of __________: organisms maintain an internalenvironment, even when the external environment changes.Answer: milieu interieurPage Ref: 5

56) The scientist __________ studied the adaptations of animals living in harsh or unusualconditions, such as the camel.Answer: Schmidt-NielsenPage Ref: 6

57) A __________ physiologist studies how an organismʹs structures and functions changethroughout life.Answer: developmentalPage Ref: 8

58) A __________ physiologist studies pressure gradients, flow, and resistance in the heart andblood vessels.Answer: cardiovascularPage Ref: 11

59) Max Kleiber used data on body mass and metabolic rate to generate the __________ equation.Answer: allometric scalingPage Ref: 11

8


60) An organism that maintains its internal environment regardless of changes in the externalenvironment is called a __________.Answer: regulatorPage Ref: 12

61) Physiological processes that change in a predictable pattern on a daily basis are said to followa __________.Answer: circadian rhythmPage Ref: 12

62) Factors that generate opposite effects on a pathway are termed __________.Answer: antagonistic controlsPage Ref: 13

63) Glucose levels in the blood are maintained by the antagonistic hormones glucagon and__________.Answer: insulinPage Ref: 13

64) The genetic makeup of an organism, the __________, can be expressed in a variety of ways andhas major effects on physiological traits.Answer: genotypePage Ref: 13

65) Environmental factors can cause __________, or a range of phenotypes from a single genotype.Answer: phenotypic plasticityPage Ref: 14

66) An animal that undergoes physiological changes caused by an experimentor regulatingenvironmental variables is said to have __________.Answer: acclimatedPage Ref: 14

67) __________ of a population occurs when environmental stressors favor survival of certaingenotypes, leading to their increased levels of reproduction.Answer: AdaptationPage Ref: 15

68) When a large portion of a population is wiped out and the genetic base is rebuilt from a smallgroup of individuals, then the __________, a type of genetic drift, may result.Answer: founder effectPage Ref: 16

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Essay Questions

69) Describe some of the factors that led to an explosion of physiological research in the 1960s.Answer: Increased numbers of scientists, improved technology, and ease of travel led to an

increase in the number of interactions and types of experiments, thus increasingscientific discovery. These interactions also included individuals from a number ofdifferent disciplines coming together to work on a single problem.

Page Ref: 2-3

70) Why was Vesaliusʹs work, which disproved some of Galenʹs earlier experiments, so important?Answer: In any scientific research it is important to have reproducibility. In the case of Galen, his

work was so renowned that no one questioned his results. Once some of the work wasshown to be incorrect, it opened the door for further research on physiological subjects.

Page Ref: 5

71) Explain how a cell and molecular physiologist can be a developmental and appliedphysiologist as well.Answer: There are a number of ways to categorize the work that physiologists do. It can be

divided by level of organization, processes, or the type of science (pure vs. applied). Inthis case a physiologist could study the process of development at the cell andmolecular level with the purpose of preventing birth defects.

Page Ref: 6-9

72) Explain why it is important to understand chemistry and physics before studying physiology.Be sure to include some examples.Answer: Physiology follows the laws of chemistry and physics. Just because an ion is diffusing in

a physiological system does not mean it will not interact with other ions or formchemical bonds. Understanding that fluids flow from areas of high to low pressurehelps one understand the cardiovascular system as well.

Page Ref: 10-11

73) How does an organismʹs body determine whether to utilize short-term or long-term strategiesfor maintaining homeostasis?Answer: It always costs energy to maintain an internal environment that may differ from the

external environment. The key question is cost versus benefit. If the difference will last along time, it will be beneficial to invest more resources early on, which will allow theorganism to maintain other functions (e.g. growing fur in winter). On the other hand, ifit is a short-term difference (e.g. hot sun at noon), then less expensive measures may bemore appropriate.

Page Ref: 12

74) How is it possible for a single genotype to generate a broad range of phenotypes?Answer: Organisms may have identical genotypes, but depending on their environment,

expression of some genes may be more beneficial than others. Thus, environmentalfactors can regulate which genes are expressed at any one point in time, allowing fordifferent phenotypes (physical expression), from a single set of genes.

Page Ref: 13-14

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75) Explain why a certain mutation in a genome may not continue to be beneficial after anenvironmental stressor is removed.Answer: Expression of certain genes always contains certain costs and benefits. In some cases,

expression of a mutated gene may be very costly in some aspects. However, if thismutation allows for survival and reproduction, the benefit outweighs the cost. On theother hand if the environmental stressor is removed, the cost may exceed the benefit.Those individuals with the mutation now lose the advantage because they areʺspendingʺ resources on a useless protein rather than one of current benefit.

Page Ref: 15

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Chapter 2 Chemistry, Biochemistry, and Cell Physiology

Multiple Choice Questions

1) The first living organism, the progenote, gave rise to many characteristics frequently found inmodern life-forms, including

A) no need for a nucleus.B) ability to survive in anaerobic conditions.C) using only twenty amino acids in proteins.D) using sulfur as an energy source.


2) Which of the following types of energy is strictly potential energy?A) mechanical energy B) radiant energyC) chemical energy D) electrical energy


3) Once the activation energy has been transferred to a molecule,A) it has reached the transition state.B) it will always return to the substrate conformation.C) it will always move on to the product conformation.D) both A and C


4) What is the correct relationship between chemical reactions and temperature?A) All chemical reactions are endothermic, and therefore require warmer temperatures.B) Warmer temperatures provide the activation energy required to start chemical reactions.C) Warmer temperatures allow more energy to be released during a chemical reaction.D) Chemical reactions are not dependent on temperature at all.


5) Which of the following types of bonds is not based on attraction of one molecule for the other,but instead is based on an uncharged moleculeʹs inability to form a bond with water?

A) van der Waals interactions B) hydrogen bondsC) ionic bonds D) hydrophobic bonds


6) The correct term(s) for the most abundant liquid in which other molecules are dissolved is/areA) solvent. B) solute. C) solution. D) both A and C


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Chapter 2 Chemisty, Biochemistry, and Cell Physiology

7) Diffusion of a solute through a solution is decreased by anA) increased concentration gradient. B) increased size of molecule.C) increased diffusion coefficient. D) increased diffusion area.


8) What is the osmolarity of a solution containing 3 M MgCl2 and 2 M glucose?A) 5 OsM B) 8 OsM C) 11 OsM D) 10 OsM


9) Two compartments are separated by a membrane that is permeable to water and urea.Compartment I contains 1 M NaCl. Compartment II contains 2 M urea. Which of the followingis a correct statement of their relationship based on the initial conditions?

A) Compartment I is isosmotic to Compartment II.B) Compartment I is hyposmotic to Compartment II.C) Compartment I is hypertonic to Compartment II.D) both A and C


10) pH is a measure ofA) [H+]. B) [OH-].C) ratio of [H+] to [OH-]. D) ratio of [OH-] to [H+].


11) Which of the following statements is true for a strong base?A) It has a low pK. B) It has a high pK.C) It easily donates [H+]. D) It dissociates slowly.


12) Some of the most common buffers in animal cells are effective becauseA) they have a pK value that is close to the normal pH of the cell.B) they can bind with H+ in a chemical reaction, forming a new product that can be

eliminated from the body.C) they have very low pK values.D) both A and B


13) Metabolic pathways that include synthetic reactions are calledA) anabolic B) catabolic C) amphibolic D) both A and C


13


14) Free energy (ΔG) represents the amount of energyA) available for use from a reaction.B) required to start the reaction.C) that could potentially be released from a reaction.D) that goes to randomness.


15) Km in the Michaelis-Menten equation representsA) the maximum amount of substrate that can be catalyzed by the enzyme.B) the amount of substrate required for the initial velocity to be half of the maximal velocity.C) the amount of substrate required to start an enzymatic reaction.D) a set constant used for all enzymatic reactions.


16) How can environmental conditions such as salt concentration, temperature, and pH physicallyaffect the enzyme itself?

A) Ions can bind to the active sites of enzymes, preventing the binding of substrate.B) Changes in temperature change the rate at which molecules interact with the enzyme.C) All these factors can disrupt the weak bonds that hold the enzyme in its active

conformation.D) These factors affect only the substrate.


17) Which of the following types of regulation involves binding to the active site?A) competitive inhibition B) allosteric regulationC) covalent modification D) both B and C


18) Why is ATP an important molecule?A) It links major pathways that release energy with those that require energy.B) It is an energy source that is found in high concentrations in cells.C) It is an energy source that is always available in large quantities.D) all of the above


19) The __________ structure of proteins involves interactions of amino acids that are found ondifferent subunits.

A) primary B) secondary C) tertiary D) quaternaryAnswer: DPage Ref: 44-45

20) Which of the following carbohydrates is a monosaccharide?A) sucrose B) lactose C) glucose D) maltose


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21) Which of the following polysaccharides performs a structural role?A) amylose B) glycogen C) chitin D) amylopectin


22) __________ is the metabolic pathway that synthesizes glycogen.A) Gluconeogenesis B) GlycogenesisC) Glycogenolysis D) Glycolysis


23) Glycolysis is an important metabolic pathway for the production of ATP becauseA) it can proceed with or without oxygen.B) it can produce ATP quickly.C) it can be used to metabolize fats and carbohydrates equally well.D) both A and B


24) All of the following are lipids, EXCEPTA) steroids. B) glycogen.C) triglycerides. D) phospholipids.


25) Glycerol molecules connected to three fatty acids are termedA) monoacylglycerides. B) diacylglycerides.C) triglycerides. D) cholesterol.


26) Cells within the adipose tissue that store lipids are calledA) adipocytes. B) fat bodies.C) hepatopancreas. D) blubber.


27) Lipids used as a major component of biological membranes includeA) phospholipases. B) sphingolipids.C) free fatty acids. D) both A and B


28) __________ enters the TCA cycle and forms NADH and FADH2, which can then be used forATP production.

A) Acetyl CoA B) GlucoseC) Pyruvate D) A fatty acid chain


15


29) Cells can regulate the rate of the TCA cycle using all the following ways, EXCEPTA) controlling the concentration of the substrate.B) controlling the concentration of the required enzyme.C) controlling the amount of energy the cell must expend for survival.D) controlling the catalytic activity of the required enzymes.


30) Electrons can enter the electron transport system via many paths. The first point ofcommonality in the ETS for all these paths is

A) complex I. B) complex II. C) cytochrome c. D) ubiquinone.Answer: DPage Ref: 58

31) Production of ATP by the mitochondrial ATP synthase is increased byA) high levels of ATP. B) high levels of ADP.C) low levels of physical activity. D) low proton motive force.


32) Which of the following is a benefit of using phosphocreatine to store energy (as compared toATP)?

A) Phosphocreatine can be used by almost any process requiring an input of energy.B) Phosphocreatine can diffuse more easily to areas needing energy.C) Phosphocreatine allows muscles to stop using ATP, conserving it for other uses.D) Phosphocreatine is produced during periods of high muscle activity.


33) What is the advantage of storing energy as glycogen rather than as lipids?A) It contains more energy per unit mass.B) It does not prevent physical functions of a cell.C) It can be mobilized very rapidly.D) both A and B


34) Using oxygen consumption or carbon dioxide production to measure the metabolic rate of anorganism is called

A) direct calorimetry. B) indirect calorimetry.C) doubly labeled water. D) gaseous exchange.


35) High concentrations of __________ indicate that a cell has plenty of energy.A) ADP B) AMP C) NAD+ D) Acetyl CoA


16


36) When an ion crosses the membrane and binds to a protein to accomplish this feat, it is usingA) passive diffusion. B) facilitated diffusion.C) active transport. D) either B or C


37) Ion channels that open or close based on changes in the membrane potential are calledA) voltage-gated channels. B) ligand-gated channels.C) mechanogated channels. D) porins.


38) Which of the following statements is true concerning secondary active transporters?A) A symporter can bind only one particle.B) An exchanger/antiporter will always be electroneutral.C) Electrogenic carriers generate a charge difference across the membrane.D) The direction in which charged particles are transported across the membrane does not

affect the electrical gradient.Answer: CPage Ref: 69

39) The main reason the interior of the cell is negative at rest is becauseA) the membrane is more permeable to Na+ than any other ion.B) the membrane is more permeable to K+ than any other ion.C) the Na+/K+ pump is electrogenic.D) it contains a much higher concentration of Cl-.


40) The cytoskeleton is composed of a variety of fibers, includingA) macrotubules. B) large filaments.C) microfilaments. D) all of the above


41) Vesicles that are produced by the ER-Golgi network may be released from the cell using theprocess of

A) exocytosis. B) endocytosis. C) phagocytosis. D) both B and CAnswer: APage Ref: 76

42) The extracellular matrix performs a variety of functions, including mediation of interactionsbetween cells. __________ is a glycosaminoglycan (GAG), which provides protection and actsas a shock absorber.

A) Collagen B) Chondroitin sulfateC) Hyaluronan D) Fibronectin


17


43) __________ are the sections of DNA used to encode RNA.A) Chromosomes B) ExonsC) Introns D) Genomes


44) Which of the following statements correctly describes the relationship between DNA, RNA,and transcription factors?

A) There is only one transcription factor for each region of DNA encoding RNA.B) Transcription factors must always bind close to the transcription start site.C) Phosphorylation is one way of regulating interactions between proteins required for

transcription of DNA.D) Transcription factors carry out the process of transcription themselves.


45) Proteins may be degraded by proteosomes becauseA) they have become damaged.B) they are labeled with ubiquitin.C) they are proteins which are rapidly degraded as part of the cellʹs control of protein levels.D) all of the above


46) Variations in proteins can arise from a SINGLE gene usingA) alternative splicing.B) different alleles.C) duplication of genetic material during crossover.D) mobile elements or jumping genes.

Answer: APage Ref: 83-84

True/False Questions

47) The term metazoan refers to single celled animals.Answer: FALSEPage Ref: 21

48) Covalent bonds are strong because electrons are shared between two atoms.Answer: TRUEPage Ref: 25

49) A semipermeable membrane allows all molecules to pass through it.Answer: FALSEPage Ref: 29

50) Buffers have the ability to mitigate the changes in pH when an acid or base is added to thesolution.Answer: TRUEPage Ref: 34

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51) Enzymatic reactions start when the product binds to the active site.Answer: FALSEPage Ref: 35

52) Increasing the starting [S] in an enzymatic reaction will always cause an increased V (initialvelocity) of the reaction.Answer: FALSEPage Ref: 37

53) An enzyme found in multiple different animals will have a similar Km, despite differentenvironmental conditions in each of the animals.

Answer: TRUEPage Ref: 40

54) Proteins in animals are created from chains of four different amino acids.Answer: FALSEPage Ref: 43

55) Animals utilize the metabolic pathway of gluconeogenesis only when energy stores are verylow.Answer: FALSEPage Ref: 48-49

56) Many animals are capable of producing all the required fatty acids for catabolic pathways.Answer: TRUEPage Ref: 52

57) All of a fatty acid is metabolized into acetyl CoA after a single trip through the β-oxidationpathway.Answer: FALSEPage Ref: 53

58) Antioxidants are useful in preventing DNA damage because they counteract the heatproduced during NADH and FADH2 oxidation.

Answer: FALSEPage Ref: 58

59) In a multicellular organism, the energy needs of the organism as a whole are given a higherpriority than the energy needs of a single cell at any point in time.Answer: TRUEPage Ref: : 61

60) Increasing the amount of cholesterol in a membrane leads to a decrease in the fluidity of themembrane.Answer: FALSEPage Ref: 65

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61) Primary active transport requires that two particles bind to the protein so that the energy fromone particle moving down its gradient can pull the other particle up its gradient.Answer: FALSEPage Ref: 68

62) The equilibrium potential and the reversal potential for a cell are interchangeable terms,assuming only one ion is being considered.Answer: TRUEPage Ref: 70

63) The primary function of mitochondria is to provide energy for the cell.Answer: TRUEPage Ref: 73

64) Exoskeletons, bone, and shells of mollusks are examples of a special type of extracellularmatrix.Answer: TRUEPage Ref: 77

65) Gene recombination involves only ʺwholeʺ genes. It can never occur with just a portion of agene.Answer: FALSEPage Ref: 84

Fill-in-the-Blank Questions

66) The second law of __________ says that the universe is moving from a state of order to one ofdisorder.Answer: thermodynamicsPage Ref: 22

67) The energy of movement is termed __________ energy.Answer: kineticPage Ref: 23

68) The __________ is formed by water molecules that surround water-soluble molecules in asolution.Answer: hydration shellPage Ref: 28

69) Molecules that can be positive or negative, depending on the pH of the solution, are called__________.Answer: zwitterionsPage Ref: 33

70) All metabolic pathways in a cell, tissue, or organism can be referred to as the __________.Answer: metabolismPage Ref: 35

20


71) Reversible enzymatic reactions eventually reach the point of __________, where the reactionsin the forward and reverse directions are occurring at the same rate.Answer: equilibriumPage Ref: 37

72) Energy is stored temporarily in reducing equivalents such as __________, and then releasedlater in oxidation reactions.Answer: NAD or NADPPage Ref: 40, 42

73) In order to ensure that some proteins are properly folded, the cells use __________, such asheat shock proteins.Answer: molecular chaperonesPage Ref: 45 -46

74) The products of glycolysis are ATP, NADH, and __________.Answer: pyruvatePage Ref: 50

75) Fatty acids with no double bonds are termed __________, and have a linear structure.Answer: saturatedPage Ref: 52

76) __________ is the process of forming acetoacetyl CoA from two acetyl CoA molecules.Answer: KetogenesisPage Ref: 54

77) Steroid hormones use __________ as a precursor molecule.Answer: cholesterolPage Ref: 56

78) The ratio between oxygen consumption and carbon dioxide production is termed the__________.Answer: respiratory quotientPage Ref: 63

79) The __________ describes how phospholipids, proteins, and other biological molecules cometogether to form a flexible cell membrane.Answer: fluid mosaic modelPage Ref: 64

80) An __________ protein is one that spans the entire membrane or is fixed in it.Answer: integral membranePage Ref: 66

81) When the potential of a cell membrane becomes less negative, or gains more positive charges,the term __________ is applied.Answer: depolarizedPage Ref: 72

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82) Winding DNA around __________ serves two major purposes: protection and compression.Answer: histonesPage Ref: 79

83) RNA is degraded by enzymes called __________.Answer: RNasesPage Ref: 82

Essay Questions

84) Your book refers to the process of diffusion and mentions that both chemical and electricalgradients may influence this process. Explain why Na+ would be influenced by both chemicaland electrical gradients, but glucose would not.Answer: Diffusion allows molecules to form random distributions based on parameters such as

charge and chemical concentration. A charged molecule such as Na+ will move into thisdistribution based on electrical and chemical relationships. Because glucose is notcharged, it will not be influenced by other, charged, molecules.

Page Ref: 23-24

85) A water molecule is held together by polar covalent bonds. Because the electrons are notshared equally in this arrangement, water exhibits many unique characteristics that arebeneficial for life (e.g. high surface tension). Discuss several of these characteristics and explainhow they are beneficial to living organisms.Answer: High surface tension results from attractive forces between water molecules. Smaller

organisms can travel across the surface of the water if they donʹt break these weakbonds. Water has a lower density when frozen, which means that it will float, insulatingaqueous habitats. Its high boiling point/heat of vaporization means that animals canutilize it for cooling. Heat/energy from the animal is transferred to the water, whichthen evaporates. Water is also an excellent solvent for charged molecules such as Na+,K+, and Cl-. The concentration of these solutes can then be used by the organism togenerate electrochemical gradients. They may also be used to alter the freezing point orosmotic pressure of an organismʹs internal environment.

Page Ref: 28

86) Temperature and pH can have profound effects on the ionization states of molecules. Explainhow they can cause these effects and why ionization is important physiologically.

Answer: Molecules are frequently connected to each other via weaker or less stable bonds. Theionization state of molecules frequently is dependent upon weaker bonds. Generally,lower temperatures make bonds more stable, and higher temperatures destabilize thebonds by decreasing or increasing molecular movements. pH also changes bondstrength by changing the concentration of hydrogen ions available to interact withmolecules. Changes in ionization of proteins can change their folding, and thereforetheir function. Since proteins are integral to cell performance, disrupting theirfunctionality will also disrupt normal processes in cells, causing possible harm to theorganism.

Page Ref: 33, 39

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87) Proteins, carbohydrates, and lipids all perform vital functions for an organism. Discuss someof these vital functions and what could happen to an animal if one of these biologicalmolecules were removed from their diet.Answer: Proteins play important roles in the structure of cells, as well as function. Receptors,

transporters, and enzymes are just a few of the functional roles proteins play.Carbohydrates are important structurally and as an energy source. Carbohydrates canbe used as a rapidly accessible form of energy, or they can be stored for later use. Lipidsare critical for membrane formation, chemical signaling, and energy sources. Withoutlipids, isolation of the intracellular and extracellular components would be impossible.

Page Ref: 43-47, 52-55

88) Release of energy from many biological molecules requires oxygen, and yet some species areable to survive in conditions having little or no oxygen (hypoxia or anoxia). What adaptationsallow them to do this?Answer: The most obvious means is to decrease the energy requirements by slowing metabolic

reactions in all or part of the tissues. This extends the supply of fuel that can be utilizedwithout oxygen. Animals can also store more of their energy as glycogen, which can bemetabolized by anaerobic glycolysis. Lastly, some animals have modified glycolyticpathways that produce end products other than lactate. These end products are lesstoxic, or can be removed easily from the body so they do not stop glycolysis.

Page Ref: 51

89) Organisms typically release more CO2 during periods of high activity. Based on yourknowledge of the TCA cycle, explain how this occurs.Answer: If activity is increased, there is an increase in the need for ATP. In order to increase ATP

production, there will be an increase in the rate of TCA cycle reactions. This leads to anincrease in the amount of NADH and FADH2 produced, which will go through theelectron transport system to provide energy for ATP production. Another by-productof the TCA cycle is CO2. Thus, when the rate of the TCA cycle increases, so does therate of CO2 production.

Page Ref: 57-58

90) There are multiple ways that particles may cross a cellular membrane. Discuss the salientfeatures of passive diffusion, facilitated diffusion, and active transport.Answer: Passive diffusion implies that no aid is given by a protein; therefore, only molecules that

are lipid soluble can cross. Passive diffusion also does not require direct energy input,so substances can move only from areas of high to low concentration. Facilitateddiffusion has the same energy parameters as simple diffusion, but utilizes a protein toenable charged molecules to cross the lipid membrane. Active transport requires thatmolecules or ions bind to the protein and that energy will be utilized. Because energy isconsumed in this type of transport, it can be used to generate gradients (i.e., ʺuphillʺtransport).

Page Ref: 66-68

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91) The Na+/K+ ATPase pump plays only a minor role in directly generating the restingmembrane potential. (The electrogenic contributions are minimal.) However, the cellʹsmembrane potential would not be possible without it. Explain how this can be true.

Answer: Although the electrogenic properties of the Na+/K+ ATPase pump cannot account forthe resting membrane potential, it does generate a large concentration gradient for bothNa+ and K+. Because of this, when a K+ channel is open, K+ is able to move through thechannel and down its gradient. The movement of the charge is a major contributor tothe resting membrane potential.

Page Ref: 70-71

92) Proteins form enzymes, transporters, channels, and many other critically importantcomponents of cells. Thus, it is essential that cells be able to regulate the amount of eachprotein that is available for use. What mechanisms are available to the cell for this regulationof protein levels?Answer: Cells may increase or decrease the rate of transcription and translation. Transcription

provides a ʺcopyʺ of the instructions (mRNA) on how to produce a protein, andtranslation is the process that assembles the primary chain of amino acids from thedirections on the mRNA. Cells can also remove existing proteins by enzymaticdigestion. The protein is labeled by ubiquitin and then taken to a proteosome fordestruction.

Page Ref: 78-83

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