Question

Which of the following is known as the energy currency of a cell?
A. Adenosine diphosphate
B. Adenosine triphosphate
C. Pyruvate
D. Glucose

Answer 1

Hint:- Cellular respiration is the process through which the C-C bond of complex compounds is broken through oxidation releasing a considerable amount of energy in the form of energy currency. The site for this process is the cytoplasm and mitochondria of the living cell.

Complete Answer:- At the time of oxidation of food within a cell, energy contained in the respiratory substrate is released. This energy is not released free into the cell or in a single step but is released in a series of stepwise reactions. This is controlled by enzymes and the energy released is trapped as chemical energy in the form of ATP i.s. adenosine triphosphate.
It carries energy in the two terminal phosphate bonds. The formation of these bonds requires a large amount of energy because they are formed against a force of repulsion between similarly charged radicals P and P.
Hence the energy released in respiration by the process of oxidation is not used directly but is used in synthesizing ATP. This ATP is utilized whenever energy is needed. Thus ATP acts as the energy currency of the cell.
Pyruvate is a chemical compound obtained as a product of the glycolysis of the glucose molecules. In the process, two molecules of pyruvate are formed from one molecule of glucose which is then used for providing the energy. This pyruvate is converted into acetyl-Coenzyme A which enters the tricarboxylic or citric acid cycle.
Glucose is a hexose monosaccharide which is also known as blood sugar.

So the correct option is 2. Adenosine triphosphate.

Note:- The energy trapped in ATP is used by organisms in many energy requiring processes and the carbon skeleton produced during respiration is used as precursors for the biosynthesis of other molecules in a cell.