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Exam 1 & Key- Winter 2002 MPP3202

Exam 1 & Key- Winter 2002 MPP3202 - SEP-lT-EEEE ii...

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Unformatted text preview: SEP-lT-EEEE ii 2- ‘C1 15:45 HEHLTH SCIENCE LIBRHRY 5738841421 P.81/11 Student name: _..__,—.__——-.—-—- Student number: Thurs/Fri - moacATss «mar Amsme ELEMENTS OF PHYSIOLOGY lst Examination February 20, 2002 TA name : Fill in the top of the question sheet and answer sheet. Include your TA's name and lab day on the question sheet. We only need your name and TA's name on the top to the answer sheet. You don't need to fill in the any circles on the front page. Circle the letter of the one best answer to each question on the question sheet and fill in the appropriate answer circle on the answer sheet. (A=l, B=2, C=3, D=4, E=5) Each answer is worth 2 points unless otherwise indicated. Turn in both the question and answer sheet. What is "physiology"? It is the study of function; how the parts of the body work. B. It 15 the study of the body's structure; how the parts of the body are related to each other. C. It is the study of the chemical reactions that take place within the body. D- It is the study of how the body changes when afflicted with disease or injury. What is meant by a mechanistic or reductionist approach to the study of physiology? A- It is an attempt to describe the workings of parts of the body as though they were machines. B. It is an attempt to describe the workings of parts of the body in terms of the functions they perform. It is an attempt to describe the workings of parts of the body in terms of physics and chemistry. D. It is an attempt to explain the workings of the parts of the body as a result of a vital force. Page 1 SEP-lT-EEEE 15:45 HEHLTH SCIENCE LIBRHRY 5738841421 P.82/11 3. What term refers to the body's ability to produce a constant internal environment with little variation in factors such as temperature? A. Set point-comparator congruence B. Low variation tolerance engineering cc. Homeostasis D- Isomorphic feedback 4- Which control system(s) tends to produce a constant internal environment within the body? A- positive feedback control i 3- negative feedback control C. either of the above D. neither of the above 5. Which type of chemical bond is strongest? I A- covalent bond 3- ionic bond C- hydrogen bond Do savings bond 5- How is an amphipathic compound best described? A. It is mostly a hydrocarbon chain. 3- It has a high molecular weight. ‘C~ It has both polar and non—polar regions. D. It has a low solubility in water. 7- What do glycogen, starch and cellulose have in common? A. They are made up of carbohydrate subunits. 3- They all have high molecular weights. C- They are all polysaccharides. ID- All of the above 3- How do polar and non-polar molecules differ? A. Electrons are uniformly distributed around non-polar molecules but not around polar ones. 3- Polar molecules are soluble in water but non—polar molecules are not. C- Polar molecules readily associate with other polar molecules but non-polar molecules don't. . D- All of the above. Page 2 SEP—lT—EBBE 15:45 HEHLTH SCIENCE LIBRHRY 5738841421 P.83/11 9‘ A textbook contains the following sentence: "A specific sequence of bases in deoxyribonucleic acid (DNA) is used to produce a specific messenger ribonucleic acid (mRNA) which is then translated on a ribosome into a specific sequence of amino acids." What process is being described? ..A. Protein synthesis 3- Cell division C. DNA replication D. Facilitated diffusion 10- What term would also be a correct answer to the above question? A. transmembrane signaling 5- homeostasis IC. gene expression D. all or none response 11- During embryonic and fetal development a wide variety of specialized cells are generated by the process of differentiation. What is true of all those cell types? A. Their differentiation began soon after fertilization in the blastocyst stage. 5- During development one specialized cell type may differentiate into another cell type. C- Similar cell types do not form tissues until late in fetal development. ID- They all differentiated from pluripotent stem cells- 12- Which statement best describes the structure of the plasma membrane of a cell? A+ It is made up largely of proteins with polar groups in contact with each other and nonnpolar groups on the outside of the cell. eB- It is made up largely of phospholipids with their nonmpolar areas contacting each other and the polar groups lining the outer and inner surfaces. C- It is made up of polar and non—polar lipids which form channels separating proteins. D- It is about equal parts of proteins and lipids separated into a patchwork of polar and nonrpolar areas. 13- Which statement characterizes the process of diffusion? A- It moves compounds from an area of high concentration to an area of low concentration. 3- It is due to random thermal motion of molecules. C- It will continue until concentration differences dissipate. 0 D- All the above characterize diffusion. Page 3 SEP—lT—EBBE 15:46 HEHLTH SCIENCE LIBRHRY 5738841421 P.84/11 14- A certain ion is shown to be moving across the plasma membrane of a cell against its concentration gradient i.e. from an area of low concentration to one of high concentration. For this to occur which of the following must also happen? A- An ion of opposite charge must cross the membrane in the opposite direction. dB. The ion's movement requires the expenditure of energy so ATP (adenosine triphosphate) is being used. C- Protein channels which span the membrane are being used to make this facilitated diffusion possible. D. The process being described does not occur in living cells. 15. A physiologist measures the uptake of glucose and cholesterol into liver cells and finds that as the concentration of glucose outside the cell rises its entry rises at first then plateaus at a maximum value. The uptake of cholesterol, however, keeps increasing as the outside concentration rises. These results are depicted below. 50 eHoLte'TE/LCL 40 Um cmtnATionJ .36 - e” m?” D astute-SE: CELL? 2o w it we 5L CONCENTRATION ouTE-(‘D Which conclusion regarding glucose uptake is best justified by these data? E (:ELLE,KH4AAJ A- Its net uptake increases as long as its outside concentration exceeds its inside concentration. Bu Its net uptake is limited by its solubility in the lipid bilayer of the plasma membrane. 1C. Its net uptake is limited because glucose carriers in the plasma membrane are limited in number and become saturated. D- Its concentration reaches a maximum because it is being rapidly metabolized in liver cells. 16+ Which conclusion regarding cholesterol uptake is best justified by these data?. A. The lack of saturation is due to a high capacity carrier protein in the plasma membrane. IE. Cholest ol concentration inside equals its outside concentration becauseAdiffusien through the lipid bilayer of the plasma membrane. C- There is no limit to the amount of cholesterol that can be taken up by liver cells. D- Cholesterol is being actively transported into the cell against its concentration gradient. Page 4 SEP—lT—EBBE 15:46 HEHLTH SCIENCE LIBRHRY 5738841421 P.85/11 17- What statementis) best characterize the plasma membrane channels involved in the movement of ions into and out of the cell? A- Their ion selectivity is based on the size of the channel and the charges within it. 3- They are regulated to allow ion movement at some times and prevent it at others. C- They all require expenditure of energy in the form of ATP hydrolysis to ADP. ID- Statements a and b are correct but c is not. 18- Which statement regarding the Na+—K+ ATPase pump is NOT true? oA- It reverses the directions in which it moves Na+ and K+ during an action potential. 3- It moves 3 Na+ ions out of the cell for each ATP hydrolyzed. C. It moves 2 K+ ions into the cell for each ATP hydrolyzed. D. It moves both Na+ and K+ against their concentration gradients 19. The Ca2+ ATPsse pump moves Ca2+ against its concentration gradient. What happens when this pump is activated in a cell? A. The Ca2+ concentrations inside and outside the cell are made equal. B. The movement of Ca2+ causes the cell to depolarize. C- 2 Ca2+ ions are moved into the cell for each ATP hydrolyzed. in. 2 Ca2+ ions are moved out of the cell for each ATP hydrolyzed. 20. Which of the following statements regarding osmosis is no: true? A. Osmosis is the movement of water across a membrane in response to the presence of different concentrations of a solute which is non— penetrating (can't cross the membrane). E. During osmosis, water moves frOm an area of lower solute cocnentration to an area of higher solute concentration. ‘C- Water movement must continue until the non—penetrating solute can cross the membrane. D. Swelling due to osmotic pressure can be great enough to cause cells to burst. 21. cells contain non-penetrating (impermeable)solutes that give their contents an osmotic strength of 300 mOsmoles/l. Normal saline is 0.9% Na Cl by weight, equivalent to 155 mM NaCl or 300 mOsmolesfl. Are the following statemetns true or false? (Fill in circle #1 for TRUE: circle #2 for FALSE.) T F. Cells exposed to normal saline will take up water and swell. 22. T F. Cells exposed to 75 mM NaCl will lose water and shrink. 23. T F. Cells exposed to 300 mM NaCl will take up water and swell. Page 5 SEP-lT-EEEE 15:47 HEHLTH SCIENCE LIBRHRY 5738841421 24- According to the Nernat equation, what is the most important variable in determining the equilibrium potential for an ion across the plasma membrane of a cell? ‘A. the conCentration difference of the ion outside and inside the cell. 3- the ability of the ion to cross the plasma membrane. C. the existing electrical potential across the membrane. D- the concentration of the ion inside the cell. 25- According to Ohm's law, what happens to electrical current if voltage is constant and resistance is doubled? A- Nothing 3- It doubles. gC- It is reduced by half. D- It is reduced by resistance squared (R2). 26. The concentration of ion x+ is 100 mM outside of cells and 1.0 mM inside. According to the Nernst equation what is the equilibrium potential for ion X+? A. + 157 mV ‘B. + 118 mV C. + 59 mV D. not enough data to calculate 27. Why is the resting membrane potential of cells (Em) near the equilibrium potential for K+ (EH)? fiA- Because, at rest, the plasma membrane is permeable primarily to K+. E. Because the K+ concentration gradient promotes loss of K+ from the cell. C. So that the cell can depolarize during an action potential. 5- Because, at rest, the voltagergated K+ channels are open. 23- How do graded potentials differ from action potentials? A. They vary with the intensity of the stimulus. 3- They decay with distance along the membrane. C. They may be depolarizing or hyperpolarizing. .D. All of the above are differences. 29. which of the following best describes a threshold potential? A- It is the membrane potential at which Na+ entering the cell is balanced by K+ leaving the cell. ‘ irE- It is the potential at which a membrane changes from being more permeable to K+ to being more permeable to Na+. C- It is the membrane potential reached at the peak of the action potential. 5- It is the electrical potential that prevents the movement of an ion down its concentration gradient. Page 6 P.86/11 SEP—lT—EBBE 15:47 HEHLTH SCIENCE LIBRHRY 5738841421 P.B?/11 30- The protein myosin A- comprises the thin filament in a muscle fiber. 3- has a tail that forms the cross—bridges. KC- has a globular head with a binding site for actin and ATP. D. is only found in fast—glycolytic fibers. 31- ‘Which of the following statements regarding the shortening of a skeletal muscle fiber is not true? When a skeletal-muscle fiber shortens, A- the sarcomeres shorten. 3- the distance between Z lines decreases. .C- the myofilaments shorten. D. the myofilaments slide past each other. E- the length of the A bands remains the same. 32- Binding of to myosin permits crosshbridge between actin and myosin. A- ATP; attachment 13- ATP; detachment calcium; attachment calcium, detachment actin: detachment m U D 33- During the cross-bridge cycle: A- ATP is hydrolyzed by actin. B‘ myosin heads interact with tropomyosin to generate force. C- Rigor crosswbridges is the predominant state. QD. Force generation is associated with the release of inorganic phosphate (Pi) from the cross—bridge. E. none of the above 34. During excitationrcontraction coupling in skeletal muscle: A. action potentials travel within the thick filaments. B. calcium channels in the thin filaments close in response to action potentials propagating down the transverse tubules. C. calcium from the sarcoplasmic reticulum binds to tropomyosin initiating action potentials. D- energized myosin heads interact with troponin on the thin filament causing muscle relaxation. .5. none of the above 35. Which is no; a function of ATP in a muscle fiber? A. Energy derived from the hydrolysis of ATP maintains K+ and Na+ concentration gradients across the sarcolemma. E. ATP binding to myosin causes myosin to dissociate from actin. C. ATP hydrolysis energizes cross-bridges. iD. ATP interacts With Ca2+ to move tropomyosin, allowing myosin to interact with actin. Page 7 SEP-lT-EEEE 15:47 HEHLTH SCIENCE LIBRHRY 5738841421 P.88/11 36. "Meter unit" refers to 1A- a single motor neuron plus all the muscle fibers it innervates. 3- a single muscle fiber plus all of the motor neurons that innervate it. all of the motor neurons supplying a single muscle. C D- a pair of antagonistic muscles. E all of the muscles that affect the movement of any given joint, 37- The amplitude of a tetanic contraction is greater than that of a twitch contraction because of: A- wave summation. 3‘ greater activator calcium inside the fibers. C- more strong binding cross—bridges. ID. all of the above 38- The molecular basis for the reduction of muscle tension over the descending limb of the length—tension relationship is: A. Thick filaments colliding with the 2 lines 3- Thin filaments from the opposite side of the sarcomere interfering with cross—bridge interactions with actin oc. Reductions in the amount of overlap between thick and thin filaments D. Reductions is stimulus intensity to the muscle E none of the above 39. According to the force—velocity relationship of skeletal muscle. A- slow-twitch muscle moves the same relative load slower than fast— twitch muscle. 3- the rate of cross~bridge cycling speeds up when the relative load is reduced. C. If the load on the muscle exceeds the force produced by the muscle the contraction is termed isometric. D. velocity of shortening is inversely related to the load on the muscle. ‘E- all of the above 40. Which of the following is not a determinant of whole—muscle tension? A- The number of muscle fibers contracting. E. The tension produced by each contracting fiber. C. The extent of motor unit recruitment. D- The frequency of motor neuron stimulation. IE- The proportion of the muscle fibers in each motor unit that are contracting at any given time. Page 8 SEP-lT-EEEE 41- Relaxation time is longer during a twitch of fatigued muscle. 15:48 HEHLTH SCIENCE LIBRHRY 5738841421 P.89/11 One likely reason for this is: A. B. .C. D. greater release of Ca2+ from the sarcoplasmic reticulum (ER). faster detachment rates of myosin from actin in fatigued muscle. slower reuptake of Ca2+ into the SR by the Ca2+ ATPase pump. slower propagation of action potentials along the sarcolemma of fatigued muscle fibers. 42. John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest. Specializes in long, Jim is a marathon runner who steady runs. Compared to Jim, John is likely to have DA. m U n m muscle fibers with a larger diameter. muscle fibers with a smaller diameter. hypertrophy of type I muscle fibers. A and C. B and C. 43. Cross-bridge activation in smooth muscle depends on A. B. C. ID. calmcdulin binding of calcium myosin light-chain kinase binding the calcium-calmodulin complex Phosphorylation of myosin all of the above 44. A major difference between smooth muscle and skeletal muscle is that CA. E. C. D. E. myosin is the regulatory protein in smooth muscle. myosin is the regulatory protein in skeletal muscle. skeletal muscle may exhibit spontaneous activity. only skeletal muscle requires increased calcium ion concentration in the cytosol for contraction. none of the above. 45. Unlike skeletal muscle, A. B. 'CL Smooth muscle is striated. smooth muscle does not have thick and thin filaments. smooth muScle does not use troponin—tropomyosin to regulate cross- bridge activity. smooth muscle does not use changes in cytosolic calcium to regulate cross—bridge activity. the myosin in smooth muscle requires phosphorylation by phosphatases before it can cyclically interact with actin. Page 9 5738841421 P.18/11 SEP—lT—EBBE 15:48 HEHLTH SCIENCE LIBRHRY 451 Excitation-contraction coupling A- in skeletal—muscle cells requires the influx of extracellular calcium ion. 3- in smoothemuscle cells requires the influx of extracellular calcium ion. C+ in both skeletal muscle fibers and smooch muscle cells involves the release of calcium ion from the sarcoplasmic reticulum. D- A and B. IE- B and C. Shown below are the results of an experiment to measure the elasticity and plasticity of a muscle (M) and a rubber band (RB). 4“” M FflRCE 30 (am) 20 KB 2 %‘ Lemmwfimfl 47. Which is more elastic? (Darken circle 1 for muscle or 2 for rubber band.) 48- Which is more plastic? {Circle 1 for muscle: 2 for rubber band) The pen tracing below Shows a Single twitch by a frcg's gastrccnemius muscle. The instrument was calibrated to move the pen 1 centimeter for each 15 grams ogiforce generated. The paper SPeEd was 100 mm/sec 4 VEKTmfiL “PEN 3 m cVEMENT (cm) 1 Inf-m. £14937?!ng l E I N. 49- How much force was genera eg at the peak of contraction A- about 10 gm 5- about 25 gm '0. about 45 gm D- about 50 gm Page 10 SEP—lT—EBBE 15: 48 HEFILTH SCIENCE L I BRFIRY 5738841421 P . 1 1/ 1 1 50- Haw long is the contractile phase of the twitch? A- about 50 msec CB. abcut 100 msec C- about 150 msec D. about 200 mSEc Page 11 TDTHL P.11 ...
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Exam 1 & Key- Winter 2002 MPP3202 - SEP-lT-EEEE ii...

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