StuDocu is not sponsored or endorsed by any college or universitySample/practice exam 12 March 2015, questionsIntroductory Biology: Comparative Physiology (Cornell University)StuDocu is not sponsored or endorsed by any college or universitySample/practice exam 12 March 2015, questionsIntroductory Biology: Comparative Physiology (Cornell University)Downloaded by yelena radutskaya ([email protected])lOMoARcPSD|34545411 Practice Prelim II BioG 1440 Name: _______________________________________________________ Student ID #: _________________________________________________ “By signing below, I acknowledge that I am abiding by Cornell University’s Code of Academic Integrity.” Signature: ___________________________________________________ WATCH YOUR TIME! This is a 50 minute exam . Total pages in exam including cover: PLEASE: 1. WRITE YOUR NAME on all pages of the exam. 2, Be sure to fill out your full name and your 7 digit Cornell ID on the scantron sheet in pencil. 3. Record answers to all multiple choice and true/false questions on the scantron sheet in pencil and directly on the exam in pen. 4. Write legibly. If we cannot read your answer, we WILL NOT grade it. 5. Use only the space provided. Answers provided outside of the space provided will not be graded. 6. Do NOT use calculators or any other electronic devices. 7. Write down the time your discussion section meets and circle the name of your TA: Time _________ Sam Dillon Nirav Patel Jonathan Fuller Katie White Sabrina Guarino Multiple choice: ____ (21 pts) Short answer: Page 5____ (8 pts) True/False: ____ (12 pts) Page 6____ (4 pts) Page 7____ (12 pts) Page 8____ (4 pts) Total Score = _____ out of 61 Downloaded by yelena radutskaya ([email protected])lOMoARcPSD|34545412 MULTIPLE CHOICE (3 points each) For each of the following questions, please choose the SINGLE BEST answer. 1. What is the primary cause of an action potential along an axon? a. A switch in the external and internal concentration of K+ b. The release of a transmitter from a presynaptic cell. c. Changes in the membrane permeabilities of ions d. The injection of current into the cell e. Decrease in the membrane permeability to Na+ 2. When an action potential arrives at the presynaptic ending which response plays a direct role in the release of the neurotransmitter? a. An increases EK b. An influx of Ca++ c. An increase in the influx of Na+ d. An increase Vm e. All of the above 3. Which of the following explains why myelination increases speed of the action potential? a. Myelination decreases the internal resistance of the axon b. Myelination decreases the membrance capacitance c. Myelination increases membrane resistance d. Both A & B are correct e. Both B & C are correct 4. Which of the following statements concerning Excitation-Contraction coupling is false? a. The transverse-tubules (T-tubules) are a continuation of the sarcoplasmic reticulum. b. The T-tubules transfer the membrane depolarization to the sarcoplasmic reticulum. c. The sarcoplasmic reticulum is a major Ca++ storage site. d. Ca++ released from the sarcoplasmic reticulum triggers the muscle contraction. e. ATP is required for excitation-contraction coupling. 5. Which statement concerning the physiology of neuromuscular junction (NMJ) is true? a. With each action potential the presynaptic ending releases a single quanta of transmitter Downloaded by yelena radutskaya ([email protected])lOMoARcPSD|34545413 b. When a toxin is used to block action potentials in the motor neuron no activity is recorded in the muscle fiber near the NMJ c. When acetylcholine binds to its receptors the associated channels opens to allow both Na+ and K+ ions to flow d. After its release at the NMJ Ach is removed from the synaptic cleft via endocytosis e. Na+ entering the presynaptic ending is directly responsible for triggering the fusion of the synaptic vesicles and the release of the neurotransmitter 6. How many neurons are needed to pass sensory information from your little toe to the toe region of your sensory cortex? a. one b. two c. three d. four 7. Which of the following is the physiological basis for the difference in sensation between fast/sharp vs. slow/burning pain? a. free vs. enclosed nerve endings in the sensory neuron b. presence vs. absence of a specialized pain receptor cell c. myelinated vs. unmyelinated axon in the sensory neuron d. short vs. long axon in the sensory neuron 8. Which of the following is NOT induced by the sympathetic nervous system? a. sweat stimulation b. skeletal muscle blood vessel constriction c. pupil dilation d. immune deactivation e. B and D SHORT ANSWERS (4 points each) Using PEN, write your answers in the space provided below, observing sentence and space limits. Think about your answer before you begin writing. 9. Why does increasing the diameter of an axon result in an increase in the propagation speed of an axon? __________________________________________________________________ _________________________________________________________________ __________________________________________________________________ Downloaded by yelena radutskaya ([email protected])lOMoARcPSD|34545414 10. A friend is studying the response of a squid giant axon to the injection of current. He has a recording electrode in the axon and is using a stimulator to inject a series of current pulses through a second electrode. The results of his experiments are summarized in the figure below. Initially your friend sets the stimulator to deliver one current pulse every 10ms. He observed that each current pulse triggered a single action potential (part A of the figure). However, as he increased the rate of the current injections he was surprised to see that they sometimes failed to trigger an action potential. Part B of the figure summarizes his results at a stimulus rate of one stimulus every 2 ms. Explain why increasing the stimulus rate can result in the failure to elicit an action potential. ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ 11. The neuromodulator dopamine plays a key role