Exam 2.07.KEY

Exam 2.07.KEY - NAME _ BIOLOGICAL SCIENCES 110-B Spring...

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1 NAME __________________________________ BIOLOGICAL SCIENCES 110-B Spring 2007 - SECOND EXAM DR. JOHNSON’S SECTION PRINT YOUR NAME (LAST NAME FIRST) ON THE COMPUTER ANSWER SHEET AND BLACKEN THE CORRESPONDING BUBBLES. THE COMPUTER ANSWER SHEET SHOULD BE USED TO ANSWER BOTH THE MULTIPLE CHOICE AND MATCHING QUESTIONS. I. Multiple Choice (3 points each): Read each of the following questions carefully. Each question has only one best answer. 1. The old saying "one rotten apple spoils the whole barrel" is due to chemical signaling in plants via . . . A) an increased uptake of carbon dioxide during respiration in target cells. B) a local regulator for apple development. C) release of ethylene gas, a plant hormone for ripening. D) an auxin signal transduction system in the rotten apple. E) a signal transduction pathway involving glycogen phosphorylase. 2. Vacuoles of plant cells are: A) typically small membrane bound compartments that reside within the nucleus. B) often used as storage compartments for secondary metabolites. C) only found in non-vascular plants. D) responsible for the plant’s photosynthetic activities. E) None of the above are true of plant cell vacuoles. 3. Neurons at rest are not at the equilibrium potential for K + because the cell membrane is . . . A) not permeable to K + . B) slightly permeable to Na + and other ions besides K + . C) not permeable to Na + . D) highly permeable to Cl - and Ca ++ ions. E) only permeable to Na + . 4. Which of the following are true of myelin: A) Formed by Schwann cells in the vertebrate peripheral nervous system. B) It is composed primarily of proteoglycans derived from the cell membranes of neurons. C) It is spatially associated with voltage gated sodium and potassium channels that are clustered at the nodes of Ranvier. D) Increases the conduction velocity of the action potential by promoting K + ion leakage out of the neuronal membrane between the nodes of Ranvier. E) A and B F) A and C
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2 5. Various drugs (e.g., oubain) can inhibit the ATP dependent Na/K pump and prevent it from pumping K + back into the cell and Na + out of the cell following an action potential. Nevertheless, following treatment with such a drug, cells are able to fire hundreds of normal action potentials. This is due to the fact that . . . A) Concentration gradients in sodium and potassium are unimportant for action potentials; they are only involved in resting potentials. B) A single action potential only involves the movement of a very small portion of the available Na + and K + ions, so it takes many action potentials to appreciably alter the concentrations of the ions. C) Concentration gradients arise solely because of “differential permeability” of the membrane to these ions and the ATP dependent Na/K pump has no effect on these concentration gradients. D) The ions will move back without need for expenditure of energy because of the “driving
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This note was uploaded on 04/07/2008 for the course BSCI 110B taught by Professor Due during the Spring '08 term at Vanderbilt.

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Exam 2.07.KEY - NAME _ BIOLOGICAL SCIENCES 110-B Spring...

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