SFSU BIOL 212 Final Exam, Exams of Biology

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SFSU BIOL 212

Final Exam

Homeostasis refers to maintaining a relatively stable internal environment. The "internal environment" is: a) the blood cells b) body parts beneath the skin c) the cytoplasm of all the cells in the body d) plasma, interstitial fluid, and transcellular fluid e) intracellular fluid - CORRECT ANSWERS-plasma, interstitial fluid, and transcellular fluid Which of the following is an example of positive feedback? a) Consuming caffeine increases urine output, causing dehydration

c) the mice lack glucagon receptors on their cells d) The mice can't synthesize glycogen from glucose - CORRECT ANSWERS-The mice lack glucagon receptors on their cells Liver cells produce glycogen in response to: a) glucagon b) insulin - CORRECT ANSWERS-insulin One of insulin's mechanisms of action is to: a) activate Na+/K+ pump b) increase the activity of SGLT c) increase the facilitated diffusion of glucose into certain cells in the body d) increase the number of sodium-linked glucose transporters in the cell membrane e) more than one of the above is correct - CORRECT ANSWERS-increase the facilitated diffusion of glucose into certain cells in the body NADH is produced from each reaction described except one. Identify the EXCEPTION. a) during "aerobic" glycolysis b) during the electron transport chain c) in the Krebs cycle d) during the conversion of pyruvate to acetyl CoA e) more than one answer applies - CORRECT ANSWERS-during the electron transport chain Under low oxygen conditions, ____________ must unload its electrons to allow glycolysis to continue its production of ATP:

a) FADH b) lactic acid c) NAD+ d) pyruvate e) NADH - CORRECT ANSWERS-NADH Which of the following statements about anaerobic metabolism is FALSE? a) oxygen is limited or absent b) pyruvate moves into the mitochondrion but then accumulates there, since the Krebs cycle does not occur c) most of the energy of the glucose molecule remains in the chemical bonds of the carbon molecule d) the electron transport chain does not occur since oxygen is needed as the final electron acceptor - CORRECT ANSWERS-pyruvate moves into the mitochondrion but then accumulates there, since the Krebs cycle does not occur From which of the following will the cell be able to harvest the most chemical energy? a) an NADH molecule b) six carbon dioxide molecules c) two pyruvate molecules d) a lactic acid molecule e) a glucose molecule - CORRECT ANSWERS-a glucose molecule Which of the following is NOT true of the cell membrane a) Cholesterol influences how fluid the membrane is b) Carbohydrates associate with proteins and lipids on the extracellular side of the membrane

c) the number of carriers in the membrane increases d) the thickness of the membrane surface increases e) more than one of the above is correct - CORRECT ANSWERS-the number of carriers in the membrane increases Which of the following transport processes is the least likely to get saturated? a) channel protein b) facilitated diffusion c) primary active transport d) secondary active transport - CORRECT ANSWERS-channel protein Which of the following statement about sodium and potassium ions is TRUE? a) the sodium ion has greater density of surface charge, so therefore it becomes less hydrated. b) the potassium ions nucleus has a larger radius, so therefore the radius of the hydrated ion will be smaller c) the potassium ions nucleus has a larger radius, so therefore the potassium ion becomes more hydrated d) more than one of the above is a true statement - CORRECT ANSWERS-the potassium ions nucleus has a larger radius, so therefore the radius of the hydrated ion will be smaller When blood sugar is low, liver cells are able to convert glycogen to glucose, thereby making the intracellular glucose concentration higher than the extracellular glucose concentration. What would happen to the facilitated diffusion of glucose throughout the GLUT when this occurs? a) the movement of glucose will not change b) the movement of glucose will stop c) the movement of glucose will reverse directions, and the glucose will leave the cell through the GLUT carriers - CORRECT ANSWERS-the movement of glucose will reverse directions, and the glucose will leave the cell through the GLUT carriers

Which of the following statements about the Na+/K+ pump is FALSE? a) three sodium ions are moved out of the cell per ATP b) It is a form of active transport c) the pump is open to both the ECF and ICF simultaneously, to allow both Na+ and K+ to move in their respective directions d) the pump has built in enzyme activity e) it is present in the cell membrane of every cell of the human body - CORRECT ANSWERS- the pump is open to both the ECF and ICF simultaneously, to allow both Na+ and K+ to move in their respective directions The primary cation outside the cells is a) sodium b) chloride c) potassium d) calcium e) magnesium - CORRECT ANSWERS-sodium Which of the following is FALSE about glucose uptake in the small intestine? a) glucose moves into the bloodstream by facilitated diffusion b) the movement of glucose across the luminal membrane is driven by an ion concentration gradient c) the co-transport carrier relies on phosphorylation in order to increase its affinity for glucose d) the sodium-potassium pump keeps the ICF Na+ concentration lower than the luminal Na+ concentration - CORRECT ANSWERS-the co-transport carrier relies on phosphorylation in order to increase its affinity for glucose A solution contains solutes to which the membrane is not permeable. If pure water and the solution are separated by a membrane: a) water will diffuse by osmosis until the solute concentration in the two compartments becomes equal

e) 3.0 OsM - CORRECT ANSWERS-2.7 OsM Assume that the cell membrane is not permeable to CaCl2 or its ions, what will happen to a RBC put into this solution? a) The RBC will swell or lyse b) The RBC will not change c) The RBC will crenate - CORRECT ANSWERS-The RBC will crenate GIVEN: The red blood cell membrane is impermeable to mannitol, but is permeable to both water and glucose. Red blood cells will swell the most when immersed in: a) A hyper-osmotic glucose solution b) a hypo-osmotic glucose solution c) a hyper-osmotic mannitol solution d) hypo-osmotic mannitol solution - CORRECT ANSWERS-hypo-osmotic mannitol solution Certain cells that line the stomach synthesizer a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following could be responsible for its crenation? a) endocytosis b) exocytosis c) diffusion d) pinocytosis e) an aquaporin - CORRECT ANSWERS-exocytosis During the hemoglobin metabolism, the breakdown products of heme become part of: a) cerebral spinla fluid b) albumin c) the globulins d) erythropoietin

e) bile - CORRECT ANSWERS-bile After the breakdown of RBCs, iron is held in the liver by: a) ferritin b) bilirubin c) hemoglobin d) heme transporters e) transferrin - CORRECT ANSWERS-ferritin The substance HES (hydroxyethyl starch) is a plasma volume expander. In the year 2000, the International Ski Federation listed HES as a banned substance for international competition. What is the likely explanation for why a skier in the Olympics might use a plasma expander? a) Increasing the plasma volume means that there is more space for the blood to carry oxygen b) Having more plasma means that the heart doesn't have to work as hard c) If a skier had an abnormally high hematocrit due to blood doping, the hematocrit could be reduced by taking a plasma volume expander d) By increasing plasma volume, less lactic acid will be produced in the muscles - CORRECT ANSWERS-If a skier had an abnormally high hematocrit due to blood doping, the hematocrit could be reduced by taking a plasma volume expander A molecule that is similar in structure to a ligand, binds to the normal ligand's receptor on a target cell, a produce similar biological response in the cell a(n): a) blocker b) protagonist c) agonist d) antagonist - CORRECT ANSWERS-agonist Typical response to ____________ messengers require a long time to develop because they necessitate transcription of mRNA and translation of that mRNA into a functional protein

c) neither direction since there is no force d) varied from cell to cell e) varies based on the concentrations of potassium in the ICF and ECF - CORRECT ANSWERS- neither direction since there is no force The equilibrium for a cation is - 20 mV. Which of the following statements about this cation is true when a cell is at resting membrane potential? (-70 mV)? a) The chemical driving force is directed into the cell and the electrical force is directed out of the cell b) Both the chemical and electrical forces are directed out of the cell c) The chemical force is directed out of the cell and the electrical force is directed into the cell d) Both the chemical and electrical forces are directed into the cell e) There is insufficient information to answer this question - CORRECT ANSWERS-The chemical force is directed out of the cell and the electrical force is directed into the cell Which is a TRUE statement about the resting membrane potential in a typical neuron? a) The membrane potential is closer to the sodium equilibrium potential that to the potassium equilibrium potential b) the membrane potential is at equilibrium for both sodium and potassium at the same time c) There is no ion movement at resting membrane potential d) The sodium-potassium pump maintains the sodium and potassium concentration gradients; having these concentration gradients is critical to maintaining a steady resting membrane potential e) more than one of the above is correct - CORRECT ANSWERS-The sodium-potassium pump maintains the sodium and potassium concentration gradients; having these concentration gradients is critical to maintaining a steady resting membrane potential During an action potential in a neuron, the repolarization of the membrane is the result of: a) sodium moving out of the cell

b) potassium moving into of the cell c) sodium moving into the cell d) potassium moving out of the cell e) both calcium and sodium moving across the cell membrane - CORRECT ANSWERS- potassium moving out of the cell The positive feedback loop that is involved in the generation of an action potential is ended by the: a) opening of activation gates on the sodium channels b) closure of activation gates on sodium channels c) opening of inactivation gates on sodium channels d) closure of inactivation gates on sodium channels e) closure of potassium channels - CORRECT ANSWERS-closure of inactivation gates on sodium channels If hypokalemia persists in the body, a) the cell membrane would be hyper polarized compared to normal resting membrane potential b) neurons would require a smaller stimulus than normal to fire c) the equilibrium potential would still be same as normal d) resting membrane potential would be closer to threshold than normal e) more than one of the above is correct - CORRECT ANSWERS-the cell membrane would be hyper polarized compared to normal resting membrane potential Which of the following statements concerning propagation of action potentials is TRUE? a)The absolute refractory period dictates whether the conduction is contiguous or salutatory b) The action potentials can undergo spatial and temporal summation c) During contiguous conduction, localized current flow causes hyper polarization of an adjacent portion of membrane d) Saltatory conduction occurs only in myelinated fibers

b) increasing serotonin release by the pre-synaptic neuron c) slowing or blocking the reuptake of serotonin from the synaptic cleft d) enzymatically degrading serotonin in the synaptic cleft - CORRECT ANSWERS-slowing or blocking the reuptake of serotonin from the synaptic cleft Which of the following statements is NOT true? a) Graded potentials can sum over time but action potentials cannot b) Graded potentials do not have refractory periods, but action potentials do c) Graded potentials and action potentials are all-or-none d) Graded potentials and action potentials can change the membrane potential of adjacent areas e) Graded potentials and action potentials can change the membrane potential of adjacent areas of the membrane through localized current flow - CORRECT ANSWERS-Graded potentials and action potentials are all-or-none Tetrodotoxin (TTX) blocks voltage-sensitive sodium channels. Which of the following would be blocked by TTX? a) Channels in the post-synaptic membrane in an excitatory synapse b) channels in the axon hillock c) channels in the post-synaptic membrane in an inhibitory synapse d) both a), and b), but not c) e) a), b), and c) are all correct - CORRECT ANSWERS-channels in the axon hillock Which of the following axons would have the fastest conduction velocity? a) diameter = 25 microns; myelinated b) diameter = 25 microns; unmyelinated c) diameter = 10 microns, myelinated d) diameter = 10 microns, unmyelinated - CORRECT ANSWERS-diameter = 25 microns; myelinated

Stimuli A and B are both above-threshold stimuli that last for one second, but stimulus A is stronger. Which of the following statements is true? a) Only stimulus A can produce an action potential b) The action potential produced by stimulus A will be larger than that produced by stimulus B c) The action potential produced by stimulus A will of longer duration than that produced by stimulus B d) Stimulus A will cause a higher frequency of action potentials e) A single action potential will be produced by both stimulus A and stimulus B. The action potentials produced from each stimulus will be identical in size and duration - CORRECT ANSWERS-Stimulus A will cause a higher frequency of action potentials Two neurons, A & B, synapse onto a third neuron, C. (Hint: draw a picture to help you visualize the scenario.) If neurotransmitter from A opens monovalent cation channels and neurotransmitter from B opens K+ channels, which of the following statements is true? a) An action potential in neuron A causes a depolarizing EPSP in neuron B b) an action potential in neuron B causes a depolarizing EPSP in neuron C c) Simultaneous, but equally frequent, action potentials in A and B will cause hyperpolarization of neuron C d) Simultaneous action potentials in A & B will cause the depolarization of neuron C than if only neuron A fired an action potential e) An action potential in neuron B will bring neuron C closer to its action potential than would an action potential in neuron A - CORRECT ANSWERS-Simultaneous action potentials in A & B will cause the depolarization of neuron C than if only neuron A fired an action potential Suppose that the electrochemical force for anion X acts to move the anion into the cell. If the binding of neurotransmitter opens channels for X- on the postsynaptic cell, then the synapse is: a) excitatory b) inhibitory c) there is not enough information to determine - CORRECT ANSWERS-

e) axon terminals from afferent neurons - CORRECT ANSWERS-afferent neuron cell bodies Where is the cell body for a motor neuron which leads to the biceps muscle? a) in the dorsal root ganglion b) in the biceps c) in the lateral horn d) in the ganglion chain just outside the spinal cord e) in the ventral horn - CORRECT ANSWERS-in the ventral horn In skeletal muscle, the binding of neurotransmitter to the motor end plate opens channels which: a) allow sodium to move out of the cell b) allow calcium to move into the muscle cell c) allow calcium to move into the cell d) allow sodium to move out and potassium to move into the muscle cell e) allow sodium to move in and potassium to move out of the muscle cell - CORRECT ANSWERS-allow sodium to move in and potassium to move out of the muscle cell When a skeletal muscle is stimulated to contract, calcium binds to: a) myosin b) troponin c) tropomyosin d) calmodulin e) myosin ATPase - CORRECT ANSWERS-troponin In skeletal muscle cells, for which of the following is ATP needed? a) to allow troponin to bind to tropomyosin b) to move calcium back into the ECF c) to allow myosin to detach from actin

d) to move calcium from its storage site into the muscle cell's cytoplasm e) more than one answer is correct - CORRECT ANSWERS-to allow myosin to detach from actin Creatine phosphate is used to convert: a) ATP to ADP b) deoxymyoglobin to myoglobin c) lactic acid to pyruvic acid d) pyruvic acid to lactic acid e) ADP to ATP - CORRECT ANSWERS-ADP to ATP A contraction that generates force and moves a load is known as ____________, whereas one that generates force without movement is known as ____________ a) isotropic/isometric b) isometric/isotonic c) isotonic/isometric d) isotonic/isotropic e) isotonic/isotonic - CORRECT ANSWERS-isotonic/isometric Which of the following does NOT affect the tension of in a whole muscle? a) twitch summation in individual fibers b) varying the number of motor units used c) motor unit recruitment d) stimulating variable portions of each motor unit e) variation in the frequency of action potentials stimulating each muscle fiber - CORRECT ANSWERS-stimulating variable portions of each motor unit weightlifting can result in a dramatic increase in skeletal muscle mass. This increase in muscle mass is primarily attributable to which of the following?