Question

Which statement is true?
a) Hydrolysis of ATP to ADP and phosphate releases about 14 kJ/mol of free energy.
b) CTP hydrolysis can be a source of chemical energy.
c) dATP is the most common source of chemical energy in cells.
d) Hydrolysis of the α, β and β, γ phosphoester bonds of a nucleotide is used as a source of chemical energy.

Answer 1

Answer:

b: CTP hydrolysis can be a source of chemical energy

Explanation:

Purine and pyrimidine nucleotides are important sources of energy that drives reactions in biological systems. These nucleotides include;

• Adenosine triphosphate (ATP), a purine nucleotide which is generally referred to as the energy currency of the cell. It is the most common and widely used.
• Guanosine triphosphate (GTP), also a purine nucleotide, is involved in signalling processes and protein sysnthesis.
• Uracil triphosphate (UTP), a pyrimidine nucleotide usually involved in the activation of glucose and galactose in the cell.
• Cytidine triphosphate (CTP), a pyrimidine nucleotide that is the main energy source in lipid metabolism.

Hydrolysis of ATP to ADP yields about 57 kJ/mol of energy, dATP acts as a substrate for DNA polymerase during replication and can also act as energy transferring molecules but definitely not the most common source of chemical energy in the cell. Hydrolysis of phosphodiester bonds of a nucleotide is significant in DNA repairs and not used as a source of chemical energy.

Hence, the correct option is b.