1. A neuron is said to e polartand A. The action potential can avel in one direc
ID: 213777 • Letter: 1
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1. A neuron is said to e polartand A. The action potential can avel in one direction only B. The soma is always at one end of the eell C. There is a difference in electrical potential acrns the mende D. It tends to cluster with other neurons in groups (called el 2. Axons generaly have which of the following ion concentrations intermally Crelaive so extemally)? A. High K, high Na', low Cr. B. High K", low Na, low CT C. Low K, high Na", low Cr. D. Low K", low Na", low Cr 3. The membrane of a typical resting neuron is largely impermeable to A. Na B. K c. cr D. proteins. 4. When voltage-gated ion channels open, ions move through these channels under the influence of A. Electrical field of the membrane potential only. the: B. Concentration gradients of the ions only. C. Combined influence of the electrical field of the membrane potential and concentration gradients of the ions. D. Metabolic pumps for the moving ions. Calculation of the "net" potential of an ion (the difference between the Va and the Eno) tells you A. 5. B. C. D. how much "force" (in electrical terms), and its direction, is acting on an ion in a resting neuron how much "force" (in electrical terms), and its direction, is acting on an ion in an active neuron. The potential difference across the membrane necessary just to balance the concentration gradient. The total potential that drives the ion during the peak of the action potential. 6. The Nernst Equation is used to find the: A. Resting membrane potential (V). B. Contribution to the membrane potential made by a particular ion. C. Equilibrium potential of an ion. D. Effect on the membrane potential of changing the concentration of an ion.Explanation / Answer
Answer to question 1 :
correct option : c).,there is a electrical potential difference across the memnbrane .
that is the cell membrane of an neuron has a different voltage potential internally and externally at all times , the concenteration of ions differ greatly , making the membrane highly negitive at rest (RMP -resting membrane potential of an axon = -70mV)and move towards zero with any stimuli , genrating an action potential.
Answer to question 2.:
correct option is b) high K+., low Na+, Low Cl-
because on a stimuli , when depolarization occurs , Na+ ions starts moving inside (Na+ gate opens ) leaving behind the cl- ions outside the cell membrane making the exterior more negitive , similarly , after some time , when it (axon membrane) has sufficiently become positive , noe Na+ ions gate closes and K+ channels open and K+ starts moving out .
Answer to question no. 3.
correct option is a) : Na+
beacause only when there is a stimuli these Na+ ions are allowed to enter the cell , otherwise at resting membrane potentials these (Na+) voltage gated channels are closed and the cell is impermeable to these ions , and does not let them enter inside them.
Answer to question 4.
correct option a) electric field of the membrane potential only .
beacuse if it would have been due to the concenteration gradient then , Na+ ion channels would not have needed the stimuli to open and for the membrane to get depolarize .
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