MCDB 111 M 2017 Thur Section quiz 1B 8/10/17 Answer each question on your scantron form. Make sure your name, perm, and MCDB 111 Summer quiz 1 appears on the answer form. Each correct answer is worth half a point. 1. In the process of moving a solute across a membrane by secondary active transport involving Na+ ions, movement of the Na+ ions a. is a consequence of primary active transport b. can occur in the opposite direction of the transported solute c. always moves with the gradient of Na+ ions i.e. from a higher to lower Na+ concentration d. is indirectly coupled to ATP hydrolysis e. all of the above 2. Resistance to electrical current flow across a membrane is a. directly proportional to the number of open ion channels b. inversely proportional the number of open ion channels c. unaffected by the number of ion channels d. dependent on the thickness of the membranes e. inversely proportional to the density of the extracellular fluid 3. The strength of response to an endocrine signal is dependent on a. The concentration of hormone b. The frequency of hormone release c. The amount of time since the last incidence of hormone release d. The distance the hormone must travel to reach its target e. The excitatory postsynaptic potential (EPSP) 4. Which of the following statements about an action potential is not true? a. Occurs when voltage reaches a threshold b. Occurs after a depolarization c. Is all-or-none; no variation in intensity d. Maintains membrane polarity e. Is propagated through the neuron 5. Which of the following is true of a sub-threshold depolarization? a. Is a type of graded potential b. Is caused by positive feedback of depolarization c. K+ outflow is << Na+ inflow d. May result from Ca2+ outflow e. Results in a reduced but still detectable neurotransmitter release 6. Which of the following is/are characteristic of homeostatic mechanisms? a. They maintain some critical biological parameter at an exact setpoint b. Most involve some type of negative feedback c. They typically involve a single organ system d. They generally cannot be reset when an organism is exposed to a different environment e. Their primary goal is to bring biological systems into equilibrium with their environment7. Many hormones and neurotransmitters commonly share this common mechanism of inactivation a. Reuptake into the releasing cell b. Inactivation via diffusion c. Enzymatic inactivation d. Binding to an inhibitory compound e. Uptake into the target cell 8. Which of the following types of transport displays saturation kinetics? a. Primary active transport b. Secondary active transport c. Facilitated diffusion d. Passive diffusion e. a, b, and c 9. Axonal transport involves a. The movement of sodium and potassium ions across axonal membranes b. The movement of calcium ions across axonal membranes c. The movement of neurotransmitters into a synapse d. The movement of neurotransmitter-filled vesicles along axonal microtubules e. The movement of mitochondria along axonal actin filaments 10. If calcium is present at 100 mM within a cell and 10 mM outside of the cell, what is the approximate Ca2+ equilibrium potential of the cell? a. 120 mV b. -30 mV c. -120 mV d. -90 mV e. 10
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