31. If the potassium leak channels are blockod, what will happen to the membrane
ID: 303252 • Letter: 3
Question
31. If the potassium leak channels are blockod, what will happen to the membrane potential? (a) The interior of the cell will become less negative (b) The intetior of the cell becomes less positive (c) The exterior of the cell becomes less negative (d) The exterior of the cell becomes less positive 32 What would happen to the membrane potential if sodium ions were allowed to flow down their concentration gradient? (a) The interior of the cell will become less negative (b) The interior of the cell becomes less positive (c) The exterior of the cell becomes less negative (d) The exterior of the cell becomes more positive 3. How can a presynaptic neuroe increase the intensity of the signal it is transmiting? (a) Increase the amount of neurotransmitters secreted (b) Change the type of neurotransminer released (c) Increase the frequency of the action potential (d) Initiate a passive speead signal 34 What is the effect of opening the velitage gated sedium channels on the membrane potential? (a) Makes the interier of the cell less negatively chargod (b) Makes the interior of the cell more negatively charged (c) Makes the interior of the membrane less positive (d) None of the above 35. When an action potential starts at one end of an ason, can it run out of energy and not reach the other erd (a) Yes (b) No (a) Of higher sodium concentrations isside the cell and higher potassium cencestrations outside the cell (b) Of sodium and potassium but the area of their concentrations (imside or outside) depends on the needs ofl the cell (c) Of higher potassium concentrations inside the cell and higher sodium concenirations outside the cell (d) By pumping sodium outside the cell and potassium is cotransported out as well 37. ATP is required in the transport of (a) All molecules across a membrane (b) Molecules through a protein channel (c) Molecules to areas of lower concentrations (d) Molecules to areas of higher concentrations 38. The net movement of uncharged, polar molecules across a semipermeable membrane froen a ow concentration to a high concentration occurs by diffusion (b) False (a) True 39. Fluidity of phospholipid bilayer is increased by (b) Double bonds between carbon atoms in the fatty acid tails (c) Shorter hydrophobic tails (d) All the above 40. All the following statements concerning transmitter-gated ion channels are true EXCEPT (a) Are Ligand-gated channels (b) Are Voltage-gated channels (c) Convert the chemical signal neurotransmitter into an electrical signal (d) Are receptorsExplanation / Answer
As according to chegg policy, I have to answer first four questions incase of MCQs. If you need any help in these questions, feel free to ask me. I am giving full explanation, so that answers will be clear to you.
1) ANSWER IS:
A) the interior of the cell become less negative
EXPLANATION:
If the potassium leak channels were blocked, the interior of the cell would becomes less negative, which means more positive charge.
Membrane potential will reduce the resting membrane potential that make the cell less negative or we can say, more positive.
As if potassium channels are blockes then positive charge accumulates in cell, and we know potassium ion is positively charged. Therefore, mmbrane potential difference shifts from a negative to zero which means depolarisation takes place .
2) What would happen to the membrane potential if sodium ions were allowed to flow down their concentration gradient?
ANSWER IS:
A) the interior of the cell become less negative
EXPLANATION:
If sodium ions allowed to flow down their concentration gradient then sodium ions flow into the cell that reduces the potential across the plasma membrane. It will make the interior of the cell less negative or more positive if enough ions flow into the cell.
Sodium ions were allowed to flow down their concentration gradient which means they would flow into the cell. So interior of the cell would have a less negative or more positive.
3) How can a presynaptic neuron increase the intensity of signal it transmits?
ANSWER IS:
C) Increase the frequency of action potentials
EXPLANATION:
A neuron cannot change the size of action potentials it transmits, it can increase the number of action potentials it transmits in a given amount of time which is the frequency of action potentials. The increased frequency of action potentials will add up through temporal summation in the postsynaptic cell that will produce an increased response.
4) What is the effect of opening the voltage-gated sodium channels on the membrane potential?
ANSWER IS:
A) makes the interior of the cell less negatively charged
EXPLANATION:
Sodium ions which are positively charged flows into the cells, down its concentration gradient will make the interior of the cell less negatively charged, or positively charged.
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