Question

Which of the following is a source of instant energy?
A.Salt
B.Glucose
C.Water
D.Starch

Answer 1

Hint: An instant source of energy is a substance that can be absorbed in the body as it is, without involving any digestion.

Complete step by step answer:
-For any substance to qualify as an instant source of energy, it should be readily absorbable. -This means it should be such that it can be utilized by the body’s cells for their metabolism.
-Of the given options, glucose is an instant source of energy. This is because it can be readily absorbed by the cells through the glucose channels in the cell membrane. The cell membrane has specialized channels for uptake of glucose called GLUT channels. GLUT means Glucose Transferase.
-Glucose is absorbed directly by cells and used in glycolysis. This leads to release of energy. The process happens instantly. Hence, glucose is termed as an instant source of energy.
-On the contrary, starch, though a source of energy, is not readily absorbed by cells in the body. This is because our body cells do not have any specific channels for starch uptake. Therefore, starch has to be enzymatically broken down before cellular uptake.

Hence option B is correct.

Additional information:
 Transport of glucose into cells is influenced by sodium uptake. The glucose channels are voltage – gated. The uptake of glucose is a process of co – transport. Both glucose and sodium ions get taken up by the cells together.

Note:
In any such question, it is possible to make an error by selecting starch because it contains two monosaccharides, hence, we might think that the energy provided by starch would be more. But the question says that we need to identify an instant source of energy and not the substance that gives the most amount of energy.