1. If the potassium leak channels are blocked, what will happen to the membrane

Question

1. If the potassium leak channels are blocked, what will happen to the membrane potential? (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 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 33. How can a presynaptic neuron increase the intensity of the signal it is transmitting? (a) Increase the amount of neurotransmitters secreted (b) Change the type of neurotransmitter released (c) Increase the frequency of the action potential (d) Initiate a passive spread signal 34. What is the effect of opening the voltage gated sodium channels on the membrane potential? (a) Makes the interior of the cell less negatively charged (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 axon, can it run out of energy and not reach the other end? (b) No (a) Yes 36. The sodium-potassium pump establishes concentration gradients (a) Of higher sodium concentrations inside the cell and higher potassium concentrations outside the cell (b) Of sodium and potassium but the area of their concentrations (inside or outside) depends on the needs of the cell (c) Of higher potassium concentrations inside the cell and higher sodium concentrations 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 from a low concentration to a high concentration occurs by diffusion (a) True (b) False 39. Fluidity of phospholipid bilayer is increased by (a) Cholesterol at certain temperatures (b) Double (c) Shorter hydrophobic tails (d) All the above bonds between carbon atoms in the fatty acid tails 40. All the followi ing statements concerning transmitter-gated ion channels are true EXCEPT (a) Are Ligand-gated channels (b) Are Voltage-gated channels the chemical signal neurotransmitter into an electrical signal (d) Are receptors

Explanation / Answer

Ans-31

Potassium are positive charge ion. During conduction of action potential, after depolarization repolarization has to be done for that potassium has to move outside of membrane which bring out more positive charges at outside and more negative charge in inside but due to blockage Potassium pump it could not possible which cause less negative charge or more positive charge inside of membrane.

So option (a)is correct

Ans-32

Sodium ion is impermeable to membrane and potassium ion is permeable to membrane, so when sodium Ion allowed to move along concentration gradient then it cause depolarization mean positive charges in inside of membrane and negative charge at outside of the membrane.

So (a)option is correct

Ans-33

Presynaptic neurone release excitatory or inhibitory type of neurotransmitter which act at receptor at post synaptic neurone so signal is intensified or inhibited.

So our (b) option is correct

Ans-34

Voltage gated sodium channel play a crucial role in action potential small but significant sodium ion move towards inside of the membrane which causes further depolarization.

So (a) option is correct

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