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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 - Answer-plasma, interstitial fluid, and transcellular fluid Which of the following is an example of positive feedback? a) Consuming caffeine increases urine output, causing dehydration b) The arrival of platelets at a wound causes the release of clotting factors which cause more platelets to arrive at the wound c) When a person stands up, blood pressure decreases because of the blood pooling in the feet and legs. As a result, the heart beats faster and blood vessels constrict in order to bring blood pressure back to normal d) both a) and b) are correct e) both b) and c) are correct - Answer-The arrival of platelets at a wound causes the release of clotting factors which cause more platelets to arrive at the wound Following an increase in body temperature, which of the following responses will NOT occur? a) an increase in skin blood flow b) an increase in skin temperature c) an increase in non-shivering thermogenesis d) an increase in sweat production e) an increase in evaporation of the skin - Answer-an increase in non-shivering thermogenesis When pyrogens are present, vasodilation is used by the body to create a fever
a) True b) False - Answer-True Mice from a certain lab strain remain healthy as long as you feed them regularly and do not let them exercise. After they eat, their blood glucose level rises slightly and then declines to a homeostatic level. However if these mice fast or if they exercise at all, their blood glucose drops dangerously. Which hypothesis best explains their problem? a) The mice have insulin-dependent diabetes b) the mice lack insulin receptors on their cells c) the mice lack glucagon receptors on their cells d) The mice can't synthesize glycogen from glucose - Answer-The mice lack glucagon receptors on their cells Liver cells produce glycogen in response to: a) glucagon b) insulin - Answer-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 - Answer-increase the facilitated diffusion of glucose into certain cells in the body NADH is produced from each reaction described except one. Identify the EXCEPTION.
b) six carbon dioxide molecules c) two pyruvate molecules d) a lactic acid molecule e) a glucose molecule - Answer-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) there are many different kinds of membrane proteins d) in certain cells, the phospholipids arrange themselves into the shape of a channel, in order to allow ions to transport across the membrane - Answer-in certain cells, the phospholipids arrange themselves into the shape of a channel, in order to allow ions to transport across the membrane The isolation of different proteins to the luminal vs. basolateral surfaces of epithelial cells is due to the presence of ____________ between the cells in the tissue a) desmosomes b) a pump c) tight junctions d) gap junctions - Answer-tight junctions the GLUT family of molecules are: a) channel proteins through which glutamic acid can travel b) carrier proteins for the facilitated diffusion of glucose c) channel proteins through which glucose can diffuse d) secondary active transport carriers, for moving both glucose and sodium e) more than one of the above is correct - Answer-carrier proteins for the facilitated diffusion of glucose Alcohol crosses the cell membranes in nerve tissue relatively easily. Therefore alcohol has a: a) high partition coefficient
b) low partition coefficient - Answer-high partition coefficient Assuming that a substance is uncharged and is transported across a membrane by facilitated diffusion carriers, according to Fick's Law, the net movement of the substance will tend to increase as: a) the membrane surface area decreases b) the magnitude of the concentration gradient decreases 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 - Answer-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 - Answer-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 - Answer-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
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 b) both water and solute will diffuse across the membrane, down their concentration gradients, until a state of equilibrium is established c) water will diffuse by osmosis until stopped by an opposing hydrostatic pressure d) because of hydrostatic pressure from the pure water, no water will move at all e) it is impossible to predict what will happen - Answer-water will diffuse by osmosis until stopped by an opposing hydrostatic pressure By definition, a solution is hypotonic to a human cell if: a) the concentration of all solutes contained in it is less than 300 mOsm b) the concentration of all membrane-permeant solutes contained in it is less than 300 mOsm c) the concentration of all membrane-impermeant solutes contained in it is less than 300 mOsm d) its osmolarity is less than 300 mOsm - Answer-the concentration of all membrane-impermeant solutes contained in it is less than 300 mOsm The atomic mass of calcium (Ca) is 40.0 and chloride (Cl) is 35.5. A young doctor needs to treat a patient with hypocalcemia (low blood calcium). The doctor gives the patient 0.9 M CaCl2. What approximate % solution is this? a) 0.1% b) 6.8% c) 10% d) 0.7% e) 0.9% - Answer-10% What is the osmolarity of this 0.9 M solution of CaCl2? a) 0.3 OsM b) 0.9 OsM c) 0.27 OsM
d) 2.7 OsM e) 3.0 OsM - Answer-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 - Answer-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 - Answer-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 - Answer-exocytosis During the hemoglobin metabolism, the breakdown products of heme become part of: a) cerebral spinla fluid b) albumin c) the globulins d) erythropoietin
Which of the following statements best describes the function of tyrosine kinase? a) It catalyzes the formation of cAMP b) It catalyzes the phosphorylation of a protein in the ECF c) It actively pumps calcium into the cell d) It catalyzes the phosphorylation of a protein inside a cell - Answer-It catalyzes the phosphorylation of a protein inside a cell A certain toxin blocks a G-protein coupled receptor whose effector protein is adenylyl cyclase. Therefore, which of the following would not be produced by the cell? a) an ion channel b) cAMP c) ATP d) insulin - Answer-cAMP If the concentration of chloride ions (Cl-) in the ICF is 10 mM and the concentration in the ECF is 108 mM, what would be the equilibrium potential for chloride? a) 63 mV b) - 31 mV c) 11 mV d) - 63 mV e) 31 mV - Answer--63 mV If the membrane potential is equal to the equilibrium potential for potassium, then what would be the direction of the electrochemical force acting on potassium? a) inward b) outward 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 - Answer-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 - Answer-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 - Answer-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 - Answer-potassium moving out of the cell
d) summation of potentials at the axon hillock - Answer-arrival of an action potential at the axon terminal When a monovalent cation channel is opened in a resting cell, which of the following is TRUE? a) Potassium moves faster than sodium because the membrane is more permeable to potassium b) Sodium moves fast than potassium because of both sodium's concentration and electrical gradients c) Potassium moves faster than sodium because potassium is closer to equilibrium d) Sodium moves faster than potassium because the sodium concentration gradient is steeper than the potassium concentration gradient - Answer-Sodium moves fast than potassium because of both sodium's concentration and electrical gradients Which of the following characteristics of an action potential is NOT a direct result of the membrane being refractory? a) the fact that action potentials do not summate b) the magnitude of hyperpolarization seen at the end of the action potential c) the maximum frequency of action potentials d) the unidirectional propagation of action potentials in a motor neuron - Answer-the magnitude of hyperpolarization seen at the end of the action potential Paxil and Prozac are SSRIs, which help treat depression by: a) acting as serotonin antagonists 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 - Answer-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 - Answer-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 - Answer-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 - Answer-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 - Answer-Stimulus A will cause a higher frequency of action potentials
c) ion channel d) G protein - Answer-ion channel Basal nuclei are: a) pocket of gray matter in the spinal cord b) pockets of white matter in the brain c) pockets of white matter in the spinal cord d) pockets of gray matter in the brain - Answer-pockets of gray matter in the brain which of the following would NOT be found within the gray matter of the spinal cord? a) cell bodies of interneurons b) afferent neuron cell bodies c) afferent neuron cell bodies d) efferent neuron cell dendrites e) axon terminals from afferent neurons - Answer-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 - Answer-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 - Answer-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 - Answer-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 - Answer-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 - Answer-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
b) it is a way to slow down the response c) it allows for the flexor to contract and the extensor to relax in response to the same afferent info d) two of the above are correct e) all of the above are correct - Answer-it allows for the flexor to contract and the extensor to relax in response to the same afferent info In response to stepping on a nail, the crossed-extensor reflex causes: a) flexion of the leg on the side of receptor activation b) extension of the leg on the side of receptor activation c) extension of the leg opposite the side of receptor activation d) flexion of the leg opposite the side of receptor activation e) extension of the arm on the side of receptor activation - Answer-extension of the leg opposite the side of receptor activation Which type of autonomic receptor binds with the neurotransmitter released from parasympathetic postganglionic fibers? a) alpha b) nicotinic c) beta- 2 d) beta- 1 e) muscarinic - Answer-muscarinic Which of these synapses does not have acetylcholine as its primary neurotransmitter? a) synapse of a postganglionic parasympathetic neuron onto a heart cell b) synapse of a postganglionic sympathetic neuron onto a smooth muscle cell c) synapse of a preganglionic sympathetic neuron onto a postanglionic neuron - Answer-synapse of a postganglionic sympathetic neuron onto a smooth muscle cell Which of the following is NOT true about the sympathetic nervous system?
a) it dominates fight-or-flight situations b) It leads to the release of both norepinephrine and epinephrine c) it emerges from the cranial and sacral regions of the CNS d) It causes decreased gastric motility e) it causes dilation of the pupils - Answer-it emerges from the cranial and sacral regions of the CNS In a clinical setting, ____________ receptor agonists would be used to open the airways when treating people suffering from asthma or nasal congestion a) alpha b) nicotinic c) beta- 1 d) muscarinic - Answer-beta- 1 Where are gap junctions found? a) single-unit smooth muscle only b) multi-unit smooth muscle only c) cardiac muscle only d) both single-unit smooth muscle and cardiac muscle e) single-unit smooth muscle, multi-unit smooth muscle, and cardiac muscle - Answer-both single-unit smooth muscle and cardiac muscle the regulation of smooth muscle contractions is mediated by the phosphorylation of: a) actin b) troponin c) calmodulin d) myosin e) protein kinase - Answer-myosin
