Question

Which one is not a coenzyme?
A) NAD
B) NADP
C) FAD
D) ATP

Answer 1

Hint: The non-protein organic molecules which assist the enzymes to initiate the rate of a chemical reaction. Coenzymes are usually derived from the water-soluble vitamin B complex. The sources of coenzymes are vitamins. They function by acting as carriers of electrons or molecular groups or by activating enzymes. Coenzymes are thermostable compounds. Coenzymes promote various metabolic reactions. Coenzymes are crucial for the biological activity of an enzyme.

Complete answer:
Coenzymes are the enzymes that catalyze biochemical reactions.
For example, NAD and NADP act as coenzymes, these are derived from niacin.
NAD and NADP are the coenzymes with enzymes of the electron transport chain to initiate the transfer of an electron from the substrate to products.
With enzyme photolyase enzyme, FAD acts as a coenzyme which catalyzes the splitting of ultraviolet-induced thymine dimers.
ATP is not a coenzyme because it does not have any property to initiate an enzyme-catalyzed reaction.
ATP can be an allosteric modulator, a product, or a substrate, a signaling molecule for an enzyme but not a coenzyme.

Hence, the correct answer is option D.

Additional Information: A coenzyme cannot work alone. Function only when paired with an enzyme.
A coenzyme can be reused many times when present in pairs with an enzyme.
Enzymes are proteins while coenzymes are non-protein molecules.
Phosphate groups such as ATP are carried by coenzymes.
Important coenzymes are Coenzyme A, Flavin adenine dinucleotide(FAD), NAD, and NADH.

Note: Coenzymes are small, non-protein organic molecules which assist the enzymes to initiate the rate of a chemical reaction. Coenzymes are usually derived from the water-soluble vitamin B complex. Coenzymes are the enzymes that catalyze biochemical reactions. For example, NAD and NADP act as coenzymes. They function by acting as carriers of electrons or molecular groups or by activating enzymes. Coenzymes promote various metabolic reactions. Coenzymes are crucial for the biological activity of an enzyme.