Exam 1 - Name Time of Class First Exam BIO 365R Spring 2010...

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Name_______________________ Time of Class____________________ First Exam- BIO 365R Spring 2010 Semester There are 36 questions, worth a total of 100 points. There are 9 pages: Make sure you have all 9 pages. DO IT NOW! Questions 1-25 below (worth 3 pts each) are Multiple Choice. Mark your answers for questions 1-25 on the Scantron. Questions 26-36 are either short answer or require a calculation. The point value of each question is given next to the question. GOOD LUCK! 1) What determines an ion species permeability across the membrane? a) the ionic concentration on both sides of the membrane b) the density of open ion channels for that ion species c) the internal membrane resistance d) the molecular weight of the ion 2) Hodgkin and Huxley received the Nobel Prize in Physiology or Medicine for their: A) use of the squid giant axon to record the action potential. B) their observations of the behavior of single channels in the squid giant axon, C) their demonstration that currents of sodium and potassium resulting from voltage-activated conductances account for the action potential, D) their demonstration of a Na-K pump in the membrane of the squid giant axon, E) all of the above. 3) The amount of current flow of an ion species across the membrane is determined by: a) Only by the driving force on the ion. b) Only by the membrane permeability for that ion. c) Only by the degree to which the membrane is de-or hyperpolarized. d) By both the driving force on the ion and its permeability. 4) The effect of de-myelinating an axon is to; A) increase membrane resistance under the axon where myelin had previously been present thereby speeding up conduction velocity; B) decrease internal resistance under the axon where myelin had previously been present thereby speeding up conduction velocity; C) decrease membrane resistance under the axon where myelin had previously been present thereby slowing down velocity or even blocking its propagation; D) increase membrane resistance under the axon where myelin had previously been present thereby slowing down velocity or even blocking its propagation. 5) The role of the differential amplifier in the voltage clamp is to: A) respond to any differences between the membrane potential and the command potential by producing a current. B) record the resting membrane potential. C) differentiate the internal and external voltages across the cell membrane. D) distinguish between capacitative and ionic currents across the cell membrane. 6) By convention, inward current is equivalent to positive ions flowing A) into the cell B) out of the cell 1
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Name_______________________ Time of Class____________________ 7) Axons from two animals are studied by an investigator. Both axons are exactly the same size, i.e., they both have the same diameter, but the membrane resistance of axon 1 is much higher than the membrane resistance of axon 2 (axon 2 has more open ion channels than axon 2). Which of the statements below correctly describes their relative
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Exam 1 - Name Time of Class First Exam BIO 365R Spring 2010...

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