Question

1. Describe one case in which you know that is necessary the use of a symport to move molecules across the membrane, Also describe the function of Na+ channels, K+ channels, and Ca+ channels in a neuron. Be specific on the type of channels that you describe.

Answer 1

Solution: The symporters are used in several instances during different cellular process. One major use is during the transport of glucose molecule from intestinal lumen into intestinal cells. Eventhough the glucose molecule can move by their own from lumen into the intestinal cell, addition of Na+ ions, th symport molecule helps transport glucose in higher frequency through glucose sodium symporter. Glucose reaching the intestinal cell reaches the basolateral side through glut 2. Whereas th sodium ions seek the help of Na+/K+ pump to transport Na+ outside the cell.

In a neuron several Na+ , K+ , Ca+ channel proteins are expressed. Some of the Na+ and K+ channels are touch sensitive channels. Reaching the threshold potential from resting membran potential, membrane opens several voltage sensitive  Na+ and K+ channels which induces drastic change in membrane potential and thereby helping the transmission of signals through neurons.