1 If you added chloride ions to a neuron a the membrane pot

1. If you added chloride ions to a neuron, __________.

a. the membrane potential would become more negative
b. the membrane potential would not be affected because it is affected only by changes in Na+ and K+ movement across the membrane
c. the membrane potential would approach \"threshold\"
d. the cell would depolarize

2. If every ligand-gated Na+ channel on a neuronal soma depolarized the cell by 2mV, how many channels would you need to activate to reach a threshold value of exactly -50mV?(Assume a typical resting membrane potential.)

a. 20

b. 10

c. 5

d. 25

Solution

1.The correct answer is :a. the membrane potential would become more negative.

Reason:The membrane potential increases with increase in chloride ions into the neurons.

2.Th correct answer is : d.25

Reason:Since for every depolarisation of cell by 2mV , a single ligand gated Na+ channel is used.For -50mV, 25 channels will be used.