1. Which of the following types of organisms lacks a nervous system? A) sea anemone B) squid C) spiders D) sponges

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1 Exam 1A 1. Which of the following types of organisms lacks a nervous system? A) sea anemone B) squid C) spiders D) sponges 2. Why are muscles always associated with some type of skeleton? A) The skeleton is always necessary to support the body against gravity. B) The skeleton is necessary for animals to grow. C) All the answer options are correct. D) The skeleton provides a storage area for calcium ions used by muscle. E) The skeleton transmits the force generated by the muscles. 3. Neurophysiological changes during learning A) involve molecular changes at synapses making the post-synaptic membrane more sensitive to input. B) require well-developed cerebral hemispheres. C) are mediated by the autonomic nervous system. D) involve changes in the size (voltage peaks) of presynaptic action potentials. 4. There is a venom made by certain marine snails that blocks voltage-gated calcium channels. If this toxin were applied to the experimental preparation of neurons, an action potential initiated in a presynaptic axon, what do you expect will happen? A) The action potential along the presynaptic axon will be normal, but synaptic vesicles will not release neurotransmitter. B) Synaptic vesicles will release neurotransmitter but the neurotransmitter will be blocked from reaching receptors. C) The action potential in the presynaptic neuron will be blocked all along the length of that neuron's axon. D) Neurotransmitter will bind to their receptors, but second messenger actions will be prevented. Page 1

2 5. Which of the following manipulations would reduce the release of neurotransmitter from a presynaptic neuron terminal? I) reduction in extracellular calcium ion concentration at the axon terminal II) increase in extracellular sodium and potassium ion concentrations at the axon terminal III) addition of tetrodotoxin to the extracellular fluid at the axon terminal A) only I B) only II C) only III D) only I and II E) only II and III 6. The diagram below represents a sarcomere from a skeletal muscle fiber. The principal protein in the bar marked A is. As the muscle contracts, the length of this bar A) actin / remains the same B) myosin / increases C) myosin / remains the same D) actin / decreases 7. The basilar membrane has varying flexibility. Activation of different regions of the basilar membrane enable perception of sounds of different: A) amplitude B) intensity C) loudness D) pitch Page 2

3 8. An animal with a hydrostatic skeleton such as an earthworm can elongate its segments (which is how it moves forward) by A) contracting extensors and flexors against the joints of the exoskeleton. B) contracting circular (circumferential) muscles and pushing the fluid-filled body cavity forward. C) contracting cartilage muscles, which pushes the fluid-filled body cavity forward. D) contracting longitudinal muscles, which puts pressure on the hydrostatic skeleton and pushes the fluid-filled body cavity forward. 9. The transduction of sound waves to voltage changes takes place: A) in the oval window, which vibrates at the same frequency as the original sound. B) as the vibrations received by the outer ear cause the eardrum to vibrate. C) within the tectorial membrane as it is stimulated by the hair cells. D) when stereocilia bend against the tectorial membrane, causing hair cell depolarization. E) in the basilar membrane as it vibrates at different locations. 10. Muscle force is increased by: A) increased motor neuron firing rate. B) increasing the distance between muscle fibers. C) increased number of activated motor units. D) A and B E) A and C Page 3

4 11. In the figure below, the panel labeled A shows a photoreceptor and its postsynaptic cell in the dark, and panel B shows it in the light. What causes the change observed in this figure? A) Depolarization of the rod cell in the light inhibits release of neurotransmitter. B) This figure is incorrect; dark and light are reversed. C) Hyperpolarization of the rod cell in the light inhibits release of a neurotransmitter. D) Hyperpolarization of the rod cell in the dark causes release of a neurotransmitter. 12. In the design of respiratory systems, A and B represent membrane barriers between the outside medium and the inside of the organism. Which would have the higher rate of diffusion, respiratory membrane A or respiratory membrane B? A) respiratory membrane 2 B) not enough information to answer C) respiratory membrane 1 D) both have the same rate Page 4

5 13. describes the process by which molecules of a substance will move from regions of high concentration to regions of low concentration (until an equilibrium is reached). A) circulation B) ventilation C) active transport D) diffusion 14. The following steps refer to various stages in transmission at a chemical synapse. 1. The synaptic vesicles release neurotransmitter into the synaptic cleft. 2. Calcium ions rush into neuron's cytoplasm. 3. The ligand-gated ion channels open. 4. An action potential depolarizes the membrane of the presynaptic axon terminal. 5. Neurotransmitter binds with receptors associated with the postsynaptic membrane Which sequence of events is correct? A) 2 --> 3 --> 5 --> 4 --> 1 B) 4 --> 2 --> 1 --> 5 --> 3 C) 1 --> 2 --> 3 --> 4 --> 5 D) 5 --> 1 --> 2 --> 4 --> 3 E) 3 --> 2 --> 5 --> 1 --> Which one of the following is the gravity-sensing organ found in shrimps that provides information about body position and orientation? A) vestibular system B) semicircular canal C) lateral line system D) statocysts 16. What would probably happen if a neuron with a long axon had one continuous myelin sheath down the length of the axon with no nodes of Ranvier? A) There could be no action potential generated at the axon hillock. B) The action potential would be generated by Ca2+ influx C) The action potential would be propagated nearly instantaneously to the synapse. D) The signal would fade because it is not renewed by the opening of more sodium channels. 17. Insects are well known for their: A) striated muscles. B) endoskeletons. C) exoskeletons. D) hydrostatic skeletons. Page 5

6 18. Which one of the following is the portion of the forebrain that regulates the endocrine system and body temperature? A) limbic system B) hypothalamus C) thalamus D) cerebrum 19. The fovea is the area of the retina:pitch A) where all blood vessels merge with the retina B) associated with high concentrations of cone cells, and that corresponds to the center of the visual field in most vertebrates C) that contains mostly rod cells, and explains why peripheral vision is limited at night D) where the optic nerve attaches to the retina, and that doesn't have any rods or cones 20. When an action potential from a motor neuron arrives at the neuromuscular junction a series of events occurs that leads to muscle contraction. Which of the following events will occur last (i.e., after all of the others)? A) ligand-gated channels open B) muscle fiber depolarization C) conformational change in troponin D) action potential propagation along T-tubules E) acetylcholine release 21. When a nerve cell is firing rapidly, it can interfere with signal transmission of neighboring cells. This phenomenon is known as: A) excitatory post synaptic potential B) adaptation C) lateral Inhibition D) accommodation 22. Deafness caused by loud sounds often results from damage to which receptor cells? A) chemoreceptors B) electroreceptors C) nociceptors D) thermoreceptors E) mechanoreceptors Page 6

7 23. Vertebrate skeletal muscle is A) dually controlled by the autonomic and somatic nervous systems. B) dually controlled by sympathetic and parasympathetic neurons. C) under the control of the sympathetic nervous system. D) under control of the somatic, and not the autonomic nervous system. E) under control of the parasympathetic nervous system. 24. The three bones of the inner ear function: A) to detect motion B) in proprioception C) to amplify sound waves that strike the tympanic membrane D) in the sense of balance 25. The conversion of physical or chemical stimuli into nerve impulses is known as: A) cellular response B) motor response C) sensory transduction D) sensory reception 26. Ball-and-socket joints allow flexion, extension, rotation, abduction (moving away from the midline of the body) and adduction (moving toward the midline). Which of the following is(are) an example of a ball and socket joint? A) the elbow B) the shoulder C) the joints between bones of the fingers D) the knee 27. An neurobiologist records the resting potential of a neuron at -70 mv. Which of the images below best portrays what happens when a neurotransmitter is applied (arrow) to the post-synaptic membrane of that neuron, resulting in the opening of ligand-gated K + channels that were closed at -90mV. A) a B) b C) c D) d Page 7

8 28. You join an expedition to climb K2 in the Himalayas at 28,350 ft. Some maniacs in your climbing team want to attempt it without using supplemental oxygen. At 21,000 ft, two of the maniacs get very sick and very flaky. They see an image of Frank Zappa on the summit and are just too happy. Why has this happened? A) Oxygen remains 21% of the atmospheric gas, but atmospheric pressure is less, causing low PO2 and symptoms of hypoxia. B) The percent atmospheric oxygen is higher at 21,000 ft, and they are suffering from oxygen toxicity. C) The percent atmospheric oxygen has dropped far below the 21% at sea level and this causes decreased PO2, causing hypoxia in the brain. D) The accumulation of CO2 in their bloodstream accounts for the visions and euphoria. E) They must have taken drugs, because PO2 and P CO2 is the same at sea level and at 21,000 ft. 29. Neurons tend to differ in their (select the best choice): A) all of above B) function. C) size and shape. D) number of extensions. 30. Rigor mortis sets in after death because ATP becomes depleted and the muscle remains in a contracted state. This is explained by the fact that in living muscle, ATP A) binds to troponin so the muscle can relax. B) binds to myosin, exposing a binding site so myosin can bind to actin. C) binds to myosin, causing myosin to detach from actin. D) binds to actin, exposing a binding site so myosin can bind to actin. E) binds to actin, causing myosin to detach from actin. 31. Why does an action potential travel in one direction down an axon? A) because the diffusion of charge can only occur in one direction B) because it needs to reach the synapse to trigger release of neurotransmitter C) because voltage-gated sodium channels are inactivated D) because voltage-gated potassium channels are inactivated Page 8

9 32. Ca2+ ions necessary for exposing myosin binding sites on the thin filament of vertebrate skeletal muscle A) are released from the sarcoplasmic reticulum in response to voltage changes in the t-tubules. B) come from synaptic vesicles in the motor neuron. C) enter the muscle fiber through acetylcholine-gated channels when motor neurons fire action potentials. Level: Easy D) enter the cell from the extracellular fluid when voltage-gated Ca2+ channels open in the plasma membrane. 33. Action potentials in vertebrate skeletal muscle fibers A) are initiated in the nucleus where the membrane contains acetylcholine receptors. B) are initiated in the sarcoplasmic reticulum of the muscle fibers. C) are initiated at postsynaptic membrane of the neuromuscular junction and propagate along the T-tubules. D) may be excitatory or inhibitory. 34. Excitatory postsynaptic potentials (EPSPs) produced nearly simultaneously by different synapses on the same postsynaptic neuron can also add together, creating. A) the refractory state B) a temporal summation C) a spatial summation D) a tetanus 35. The power stroke corresponds to which event in muscle contraction? A) sliding of actin with respect to myosin B) cocking of the myosin head C) binding of the myosin head to actin D) cross-bridge formation. 36. The human retina has several layers of cells/tissues in the eye. What is the order of appearance of these cells from the front (where light hits first) to the back of the eye? A) pigmented epithelium; rods and cones; ganglion cells; bipolar cells B) rods and cones; bipolar cells; pigmented epithelium; ganglion cells C) ganglion cells; bipolar cells; rods and cones; pigmented epithelium D) rods and cones; ganglion cells; bipolar cells; pigmented epithelium Page 9

10 37. Cross-bridges form between the contractile proteins of the muscle cell. The movement of cross-bridges shortens the muscle fiber. What two proteins participate in crossbridge formation? A) troponin and myosin B) tropomyosin and actin C) troponin and tropomyosin D) actin and myosin 38. Where is the visual cortex of the brain found? A) the cerebellum B) the parietal lobe C) frontal lobe of the cerebrum D) the occipital lobe 39. Tetrodotoxin blocks voltage-gated sodium channels and ouabain blocks sodiumpotassium pumps. If you added both tetrodotoxin and ouabain to a solution containing neural tissue, what responses would you expect? A) slow decrease of resting potential and action potential amplitudes B) larger action potentials C) immediate loss of action potential with gradual loss of resting potential D) immediate loss of resting potential E) No effect; the substances counteract each other. 40. Which set of steps best accounts for the role of the axon hillock in nerve cell activity? A) summation, refractory period, threshold, action potential B) depolarization, summation, threshold, action potential C) threshold, refractory period, depolarization, action potential D) threshold, action potential, refractory period, summation 41. A sample of muscle tissue shows large-diameter fibers that are white in color. Which of the following characteristics would also be associated with this tissue? A) aerobic respiration B) high rates of ATP hydrolysis C) abundant mitochondria D) All of the answer options are correct E) greater resistance to fatigue Page 10

11 42. How would an abnormally large oval window in a mouse affect that animal's hearing? A) Hearing ability would be reduced in comparison with normal mice. B) Hearing is not affected by the size of the oval window. C) The mouse could detect noise in a much broader range of frequencies. D) The mouse could detect noise at much lower volumes. 43. When mosquitoes search for their next blood meal, their sensory receptors respond to CO2 levels. Which of the following types of receptor is functioning? A) a thermoreceptor B) a nociceptor C) a chemoreceptor D) a mechanoreceptor 44. My current instructor in this BIOS 1710 course is: A) General Robert Lee B) Dr. Daewoo Lee C) Dr. Garrett Sisson D) Dr. Jet Li 45. Diagram below shows a stimulus applied to a sensory cell, and diagram b is the pattern of action potentials generated in response. Such a pattern: A) allows an animal to constantly measure the strength of a continuing input. B) permits discrimination between different kinds of stimuli. C) allows an animal to detect the onset of a new stimulus. D) improves the simultaneous detection of two kinds of stimuli; for example, smell and taste. 46. Which of the following statements is true regarding respiration in fish? A) Oxygen enters the bloodstream via crosscurrent exchange. B) Gas exchange occurs at the alveoli. C) Oxygen moves through spiracles. D) Gas exchange occurs at the lamellae. Page 11

12 47. Imagine a planet that has a similar atmospheric pressure to Earth (760 mmhg), but different concentrations of gases in its atmosphere. On this hypothetical planet, oxygen makes up 40% of the atmosphere, nitrogen makes up 15%, and carbon dioxide makes up the remaining 45%. Based on this information, what is the partial pressure of oxygen on this new planet? A) 152 mmhg B) 304 mmhg C) 380 mmhg D) 228 mmhg E) 76 mmhg 48. Which one of the following are muscles that can contract, making the lens rounder to focus on close objects, and can relax to flatten the lens, enabling focus on distant objects? A) lateral rectus muscle B) Iris C) lens muscles D) ciliary muscles 49. The major inhibitory neurotransmitter of the human brain is. A) gamma-aminobutyric acid (GABA) B) acetylcholine C) serotonin D) dopamine E) glutamate 50. Which of the following is not associated with salutatory propagation? A) extremely low threshold potential B) variable concentration of voltage-gated Na + and K + channels along the axon C) faster signal transmission D) myelation E) nodes of Ranvier Page 12