Name: __________________________ 1 Biology 449 - Animal Physiology Spring 2007 Final Exam – Key (incomplete) Fill in your scantron form as follows: • Write and bubble in your name in the upper left (last name first). • Sign your form in the upper right. By so doing you verify that you are abiding by Creighton’s policy on academic honesty. Multiple choice: As always, choose the best answer for each multiple-choice question. Answer on your scantron form. Each question is worth 3 points. 1. In class this semester we have talked a lot about the sodium levels, glucose levels, H+ levels, etc., in the “internal environment.” By this, we mean a. the extracellular fluid. b. the intracellular fluid. c. the urine. d. the lumen of the gut. e. More than one of the above. 2. Consider two solutions of uncharged particles. Each contains different amount of the solutes X, Y, and Z. If the barrier between the solutions is permeable only to X, which of the following will be true? a. X will diffuse across the barrier until the concentration of X on both sides is equal. b. X will diffuse across the barrier until the concentration of X on each side equals the concentration of Y and Z on that side. c. X will diffuse across the barrier until the concentration of X on each side equals the concentration of Y and Z on the other side. d. X will diffuse across the barrier until the total osmolarity on both sides is equal. e. X will not diffuse across the barrier. 3. When applied to movement across membranes, the term “active transport” refers specifically to the fact that a. channel proteins are involved. b. carrier proteins are involved. c. cotransport is involved. d. there is a cost in energy for the transport. e. the movement is driven by osmotic differences. 4. Which of the following gives the correct sequence of events for channel activity during an action potential in an axon? a. K+ channels open, K+ channels close & Na+ channels open, Na+ channels close. b. K+ channels close, K+ channels open & Na+ channels close, Na+ channels open. c. Na+ channels open, Na+ channels close & K+ channels open, K+ channels close. d. Na+ channels close, Na+ channels open & K+ channels close, K+ channels open. e. Axons don’t show action potentials.2 5. Action potentials propagate faster along myelinated axons than unmyelinated ones because a. the insulation provided by the myelin means that depolarizations spread further along the axon. b. the myelin is a better electrical conductor than the axon itself. c. less time is wasted producing extra action potentials in the myelinated region. d. action potentials have a greater amplitude at the nodes of Ranvier. e. action potentials last longer at the nodes of Ranvier. 6. If a postsynaptic neuron is said to be showing spatial summation, then you would know for certain that a. there are two or more excitatory presynaptic neurons. b. there are two or more inhibitory presynaptic neurons. c. there are two or more presynaptic neurons of unknown type. d. there could be as few as one presynaptic neuron. e. None of the above is true. 7. Which of the following best describes sensory adaptation? a. Amplification of a weak stimulus by a G-protein system b. Two sets of sensors most sensitive to different intensities of a stimulus. c. The withdrawal reflex in response to extreme stimuli. d. The transduction of sensory information as action potential frequencies. e. A change in the response of a sensor to a constant level of stimulation. 8. The semicircular canals provide information on a. linear movements. b. rotational movements. c. air pressure changes. d. osmotic concentration. e. blood temperature. 9. How does the mammalian ear distinguish different frequencies of sound? a. The frequency of action potentials in the afferent neurons is proportional to the rate at which the stereocilia of the hair cells are being moved back and forth. b. The frequency of action potentials in the afferent neurons is proportional to the magnitude of movement of the stereocilia. c. Hair cells with different lengths of stereocilia respond to different frequencies. d. The vestibular and basilar membranes in different regions of the cochlea vibrate most strongly in response to different frequencies of sound. e. The mammalian ear cannot distinguish different frequencies.3 10. The molecule in rod photoreceptors that changes conformation when struck by a photon is a. cyclic GMP. b. opsin. c. phosphodiesterase. d. retinal. e. transducin. 11. An autocrine agent is a chemical messenger that a. activates receptors on the cell that released it. b. diffuses to nearby cells and potentially activates receptors on those. c. travels through the bloodstream and potentially activates receptors on cells throughout the body. d. is associated with the immune system. e. is associated with the reproductive system. 12. Which of the following shows the correct sequence in the chain of hormones associated with the stress response? a. Adrenocorticotropic hormone → cortisol → corticotropin releasing hormone b. Corticotropin releasing hormone → adrenocorticotropic hormone → cortisol c. Cortisol → corticotropin releasing hormone → adrenocorticotropic hormone d. Adrenocorticotropic hormone → corticotropin releasing hormone → cortisol e. Corticotropin releasing hormone → cortisol → adrenocorticotropic hormone 13. Given what you know about thyroid hormones, which of the following is the most likely mechanism by which they help increase Na+/K+-ATPase activity? a. The hormones bind to and activate Na+/K+-ATPases already present in the cell membrane. b. The hormones activate G-protein complexes that directly activate Na+/K+-ATPases already present in the cell membrane. c. The hormones activate G-protein complexes that activate secondary messengers that activate Na+/K+-ATPases already present in the cell membrane. d. The hormones activate G-protein complexes that activate secondary messengers that promote the insertion of stored Na+/K+-ATPase into the cell membrane. e. The hormones cause the increased production of mRNA for Na+/K+-ATPase, which leads to the production and insertion of additional ATPase. 14. Levels of growth hormone peak during a. childhood. b. puberty. c. early adulthood. d. middle age. e. old age.4 15. Which of the following molecules produces the force that muscles exhibit when they contract? a.