Q&A Hero

Q: Sensory neurons for muscle position are the fastest conducting neurons.

Q: An inactivated ion channel will respond to a strong stimulus.

Q: Repolarization is accomplished through a A. positive feedback loop. B. negative feedback loop. C. relative refractory loop. D. sodium equilibrium potential.

Q: Both depolarization and repolarization are produced by the diffusion of ions down their concentation gradient.

Q: Axons require ATP to produce an action potential.

Q: What is NOT true of the relative refractory period? A. Na+ channels are inactivated B. many Na+ channels are returning to a closed state C. K+ is moving out of the axon through its open channels D. a strong stimulus could cause a depolarization

Q: The ability of a neuron to transmit charge through its cytoplasm is called cable properties and is very A. good. B. strong. C. poor. D. easy.

Q: Conduction without decrement means that action potentials transmitted down an axon will not decrease in amplitude.

Q: Action potentials would be conducted most rapidly by A. a 10 mm diameter myelinated axon. B. a 10 mm diameter unmyelinated axon. C. a 40 mm diameter myelinated axon. D. a 40 mm diameter unmyelinated axon.

Q: The minimum depolarization needed to open Na+ gates is called the A. repolarization. B. threshold. C. refractory period. D. All-or-none law.

Q: Action potentials frequency encodes stimulus intensity.

Q: During the absolute refractory period, a supramaximal stimulus can bring the cell to threshold.

Q: The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the A. repolarization. B. absolute refractory period. C. relative refractory period. D. Repolarization and relative refractory period are correct.

Q: Which ion's movements is responsible for repolarization? A. influx of K+ B. influx of Na+ C. outward diffusion of K+ D. outward diffusion of Na+

Q: What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations? A. after-hyperpolarization B. all-or-none-law C. Na+/K+ pump D. refractory period

Q: What coding system do neurons use to get a greater response? A. greater amplitude of stimuli B. greater Na+ concentration gradient C. increased frequency of stimuli D. more active Na+/K+ pump

Q: As the intensity of a stimulus increases, more axons will become activated. This process is called A. threshold. B. refraction. C. recruitment. D. None apply.

Q: Local anesthetics block conduction of action potentials in sensory neurons by A. inhibiting the release of acetylcholine. B. binding to potassium channels. C. binding to sodium channels. D. binding to calcium channels.

Q: The mechanism that allows many Na+ ions to move into the axon is A. negative feedback. B. positive feedback. C. equilibrium feedback. D. None of the choices are correct.

Q: An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the A. All-or-none law. B. recruitment law. C. graduated law. D. threshold law.

Q: Cells become more negative during hyperpolarization.

Q: The membrane of resting nerve cells is more permeable to ____________ ions than ____________ ions. A. sodium, potassium B. calcium, potassium C. potassium, sodium D. chloride, potassium

Q: The average resting membrane potential of a neuron is -85mV.

Q: The average resting membrane potential of an axon is A. -70mV. B. -85mV. C. 0 mV D. +30mV.

Q: Ion channels that open in response to depolarization are called A. ion-gated channels. B. voltage-gated channels. C. stimulation-gated channels. D. potential-gated channels.

Q: Nerve cells depolarize due to the influx of K+.

Q: Blocking ____________ channels would prevent neuron depolarization. A. K+ B. Cl- C. Na+ D. Mg2+

Q: During an action potential A. Na+ efflux causes depolarization. B. K+ influx causes repolarization. C. Na+ influx causes depolarization. D. K+ influx causes after-hyperpolarization.

Q: What type of cell signaling occurs through the extracellular matrix to nearby target cells? A. endocrine signaling B. synaptic signaling C. gap junctions D. paracrine signaling

Q: What type of cell signaling uses chemicals called neurotransmitters to innervate its target organ? A. synaptic signaling B. paracrine signaling C. endocrine signaling D. gap junctions

Q: The blood-brain barrier may prevent medications from reaching brain tissue.

Q: Excitable cells are incapable of maintaining a constant resting membrane potential.

Q: All cells have a membrane potential.

Q: What molecules pass information from the polar regulatory molecule receptor to activate the enzymes that produce cAMP? A. paracrines B. G-proteins C. GTP D. None apply.

Q: Which of the following is NOT a G-protein? A. alpha B. beta C. delta D. gamma

Q: Where is the G-protein complex when a regulatory molecule is not bound to its receptor? A. The alpha subunit is attached to the inner surface of the receptor. B. The three subunits are together but not attached to the inner surface of the receptor. C. The three subunits are together AND attached to the inner surface of the receptor. D. The beta and gamma subunits are attached to the inner surface of the receptor.

Q: Which G-protein subunit binds GDP? A. alpha subunit B. beta subunit C. gamma subunit D. delta subunit

Q: Where is the receptor for a nonpolar, lipid-soluble regulatory molecule? A. embedded in the outer surface of the plasma membrane B. embedded in the inner surface of the plasma membrane C. in the cytoplasm or nucleus of the cell D. All apply.

Q: Ions like Ca2+ can be second messengers for cell signaling.

Q: Hyperkalemia would ____________ the resting membrane potential of the cell. A. increase decrease C. have no effect on

Q: Most cells have a resting membrane potential between A. +60mV and -90mV. B. -60mV and -90mV. C. -65mV and -85mV. D. +65mV and +90mV.

Q: The Na+/K+ pump A. establishes equilibrium concentrations of sodium and potassium ions. B. is an electrogenic pump. C. is an example of secondary active transport. D. interferes with glucose transport.

Q: Which of the following is NOT a general category of cell signaling molecules? A. endocrine signaling B. enzymatic signaling C. paracrine signaling D. synaptic signaling

Q: What is necessary for a target cell to respond to a cell signaling molecule? A. being close together B. a second messenger C. specific receptor proteins D. All apply.

Q: What structures are used for direct cell to cell signaling? A. desmosomes B. tight junctions C. exocytosis vesicles D. gap junctions

Q: Which regulatory molecule cannot enter its target cell? A. epinephrine B. acetylcholine C. nitric oxide D. epinephrine AND acetylcholine

Q: What determines how a regulatory molecule influences its target cell? A. polarity and solubility B. solubility and size C. size and polarity D. polarity, solubility, and size

Q: Which of the following is NOT true of cyclic AMP? A. It is found on the outside of a plasma membrane. B. It is a second messenger for polar regulatory molecules. C. It is made from ATP. D. It activates enzymes inside a cell to produce the desired effect.

Q: Whose equation allows one to calculate equilibrium potential for a particular ion? A. Avogadro's B. Nernst's C. Fox's D. Dalton's

Q: Bulk transport is required for the transport of large polar molecules into or out of cells.

Q: Inhibition of receptor-mediated endocytosis A. could induce hypercholesteremia. B. could induce diabetes mellitus. C. could prevent diabetes mellitus. D. could prevent heart disease.

Q: Movement of large molecules into a cell is called A. endocytosis. B. exocytosis. C. bulk transport. D. endocytosis AND bulk transport.

Q: Epithelial cells have a polarity dealing with transport.

Q: The charge difference across a membrane produces the membrane potential.

Q: The Na+/K+ pump creates a ____________ charge inside the cell. A. positive negative

Q: The primary intracellular cation is A. Ca2+. B. K+. C. Mg2+. D. Na+.

Q: The sodium equilibrium potential using an extracellular Na+ concentration of 145 mEq/L and an intracellular concentration of 14 mEq/L would be about A. -90mV. B. +62mV. C. -62mV. D. +90mV.

Q: The resting membrane potential is closest to the equilibrium potential for A. sodium ions. B. chloride ions. C. calcium ions. D. potassium ions.

Q: If the intracellular concentration of Ca2+ was 10mEq/L and the extracellular concentration was 150mEq/L, the Ca2+ equilibrium potential would be A. -35.9mV. B. -71.8mV. C. +35.9mV. D. +71.8mV.

Q: Poisoning the Na+/K+ pump would A. generate a more negative membrane potential. B. increase cellular permeability to Na+. C. inhibit secondary active transport. D. increase cellular permeability to K+.

Q: Desmosomes are a type of junctional complex.

Q: What type of junctional complex will prohibit paracellular transport? A. tight junctions B. adherens junctions C. desmosomes D. gap junctions

Q: Transport of materials through an epithelial cell is called A. paracellular transport. B. transcellular transport. C. bulk transport. D. exocytosis.

Q: Which of the following is true of oral rehydration therapy? A. It is used to treat severe diarrhea. B. The presence of glucose aids the intestinal absorption of Na+ and water. C. It saves more than a million small children per year. D. All apply.

Q: ORT is based on understanding transport mechanisms and junctional complexes.

Q: The transport of molecules out of the urinary filtrate and into the blood is called A. absorption. B. reabsorption. C. countertransport. D. symport.

Q: The transport of amino acids across epithelial membranes requires the A. Na+/K+ pump. B. Ca2+ pump. C. Na+/H+ pump. D. facilitated diffusion.

Q: Secondary active transport A. utilizes energy directly. B. often utilizes symport proteins. C. always uses the influx of sodium ions. D. is only important in the kidney.

Q: Which of the following is NOT a primary active transport pump? A. GLUT4 B. calcium pump C. sodium/potassium pump D. proton pump

Q: Active transport carriers are also called A. vesicles. B. channels. C. pumps. D. receptors.

Q: The calcium pump is also an ATPase enzyme.

Q: The ATPase enzyme A. adds a Pi to ADP. B. powers endocytosis. C. couples Na+ to glucose. D. hydrolyzes ATP into ADP and Pi.

Q: The Na+/K+ pump transports _______ into the cell and ________ out of the cell per cycle. A. 3Na+, 2K+ B. 2Na+, 3K+ C. 3K+, 2Na+ D. 2K+, 3Na+

Q: The Na+/K+ pump A. is an example of primary active transport. B. generates a positive membrane potential. C. actively transports 2 potassium ions out of the cell. D. actively transports 3 sodium ions into the cell.

Q: Which of the following is a function of the steep Na+/K+ gradient across the cell membrane? A. provides energy for coupled transport B. creates electrochemical impulses C. maintains osmotic pressure D. All apply.

Q: Secondary active transport often occurs as a coupled transport process.

Q: In secondary active transport, if the other substance is moved in the same direction as Na+, it is called A. cotransport. B. symport. C. antiport. D. cotransport AND symport.

Q: Poisoning the Na+/K+ pump would cause the volume of the cell to __________. increase B. decrease C. remain the same

Q: In the Na+/K+ pump, three sodium ions from inside the cell must enter the carrier first.

Q: Where are GLUT carriers located in an unstimulated muscle? A. in the plasma membrane facing the external environment B. in the plasma membrane facing the internal environment C. within cytoplasmic vesicles D. There are no GLUT carriers present.