Energy currency of the cell is -

Ans. is 'b' i.e., Nucleotide triphosphate o Energy is stored in bonds between phosphoric acid residues and certain organic compounds. Because the energy of bond formation in some of these phosphates is particularly high, relatively large amounts of energy (10-12 kcal/mol) are released when the bond is hydrolyzed. Compounds containing such bonds are called high-energy phosphate compounds, the most important high-energy phosphate compound is adenosine triphosphate (ATP). This ubiquitous molecule is the energy storehouse of the body.High energy compoundso The energy released during oxidation of monosaccharides, fatty acids and amino acids may not be required immediately. Therefore, there must be some way of storing energy. The energy released during catabolism is captured in the form of a group of compounds known as "high-energy phosphates". The most important member of this groupis ATP.o A compound that liberates 7 Kcal/mol or more on hydrolysis is called high energy compound, or a compound that on hydrolysis undergoes a large (>-7 kcal/mol) decrease in free energy (DG) under standard condition is called high energy compound, i.e., DG >- 7 Kcal/mol. For example, ATP liberates 7.3 Kcal/mol on hydrolysis.High energy compounds are: -Phosphate compounds : Nucleotides (ATP Q, GTP, UTP, UDP-glucose), Creatinine phosphate Q, arginine phosphate, 1,3-bisphosphoglycerate, Phosphoenol pyruvate, inorganic pyrophosphate. Carbamoyl phosphate Q, amino acyl adenylate (amino acyl AMP).Sulfur compounds : - CoA derivatives (acetyl CoA Q, Succinyl CoA, fatty acyl CoA, HMG CoA), S-adenosyl methionine (SAM), adenosine phosphosulfate.o A compound which liberates < 7 Kcal/mol on hydrolysis is called low energy compound, i.e., a decrease in free energy' is < 7 Kcal/mol, i.e., DG < -7 Kcal/mol. Low energy compounds are glucose-1-phosphate, fructose-6-phosphate, glucose-6-phosphate, glycerol-3-phosphate, AMP, ADP Q.