Question

Which of the following is true?

a)When the neuron is in the resting state there is no potential across the membrane.

b)The concentration of Na⁺ is higher inside the nerve cell than outside the cell in the resting state.

c)Na⁺ and K⁺ ions move into and out of the nerve cell by diffusion across the membrane.

d)Negatively charged proteins move from outside the nerve cell to the inside to help establish a negative potential gradient in the resting neuron.

e)Curare results in overstimulation of the sympathetic nervous system.

f)Scopolamine produces tachycardia.

g)Saltatory conduction increases the rate at which nerve impulses are transmitted.

h)Every neurotransmitter released into the synaptic gap must find its way to a receptor site on the neighboring neuron for proper nerve transmission.

i)Malathion must be bioactivated before it is an effective neurotoxin.

j)Dermal exposure to organophosphate pesticides is a significant exposure route.

k)Atropine would be an effective antidote to poisoning by DDT.

Answer 1

(a) The resting potential of cells in neuron is -70 milivolt. This means the cells of neuron has potential 70 mvolt less than outside cells. Due to the potential difference, there is a potential across the membrane.

The statement is false.

(b) In resting neutrons, there is concentration gradient of Na+ across the membrane. Here the concentratio of Na+ ion is more inside the cell than the outside cell. So Na+ is pumped out from cell.

So, the above statement is true.

(c) In resting neutrons, there is concentration gradient of Na+ across the membrane. Here the concentratio of Na+ ion is more inside the cell than the outside cell. So Na+ is pumped out from cell by diffusion. And to balance, Na-K pump worksd which allows K+ to enter inside cell by diffusion.

The above statement is true.

(d) The above statement is true.