Question

Channels of the TRP family are required for sensing stimuli in many organisms. TRPQ is member of this family and opens in response to heat. TRPQ is a nonspecific cation channel and is found in the sensory neurons that detect heat. Sensory neurons like other neurons can fire action potentials. Suppose that you conduct an experiment with a type of worms that have TRPQ channels in their sensory neurons. You exposed the worms to heat;

1. Ca++ :

a. flows out of the cell b. flows in to the cell c. shows no significant movement across the membrane

2. Na+ :

a. flows out of the cell b. flows in to the cell c. shows no significant movement across the membrane

3. Cla :

a.flows out of the cell b. flows in to the cell c. shows no significant movement across the membrane

4. You expect the cell to become : a. hyperpolarized b. depolarized

Please, justify your answer for each question part

Answer 1

1. CA++ : b. flows into the cell.

When the action potential reaches the axon ending, it causes the calcium ion (Ca++) to enter the cell, which in turn causes the vesicles to release neurotransmitters into the synaptic gap.

2. Na+ : b. flows into the cell.

When a neuron is fired, the sodium gates respond by opening and letting positively charged sodium ions in, so that the inside starts to become less negative and ultimately positive.

3. Cla : c. shows no significant movement across the membrane.

The Cla is not involved in this process.

4. You expect the cell to become : b. depolarised.

This is because the entry of the positively charged ions reverses the polarity of the membrane inside the neuron.