(a) Amino acid - Leucine

(b) Sugar - Lactose

(c) Nucleotide - Adenosine triphosphate

(d) Fatty acid - Palmitic acid

Oxidoreductase is an enzyme that catalyses oxidation and reductions reactions. This enzyme is associated in catalysing the transfer of $e^{-}$from one molecule (the reductant), also called as electron donor, to another molecule (the oxidant), also called as electron acceptor.

The complete reaction is

Prosthetic groups are organic compounds that are tightly bound to the apoenzyme, (an enzyme without cofaetor) by covalent or non-covalent forces, e.g., in peroxidase and catalase, which catalyse the breakdown of hydrogen peroxide to water and oxygen, haeme is the prosthetic group and it is a part of the active site of the enzyme.

Co-factor is small, heat stable and non-protein part of conjugate enzyme. It may be inorganic or organic in nature.

Co-factors when loosely bound to a enzyme is called coenzyme and when tightly bound to apoenzyme is called prosthetic group.

In both the amino acids the common substituent groups are $\mathrm{NH}_2 \mathrm{COOH}$ and H .

(a) Cotton fibre-Cellulose

(b) Exoskeleton of cockroach - Chitin

(c) Liver-Glycogen

(d) Peeled potato - Starch

Cellulose is a long chain of linked glucose molecules and is the main component of plant cell walls. Cotton is the purest natural form of cellulose. the cellulose content of cotton fibre is $90 \%$.

Chitin is a long chain polymer that forms the hard part of the outer integument or exoskeleton of crustaceans and insects such as cockroach. It is also the main component of the cell walls of fungi.

Glycogen is a multibranched polysaccharide of glucose acting as a form of stored energy in the liver of animals. It is also found in some stored fungi.

Starch is a carbohydrate consisting of along chain of glucose units joined by glycosidic bonds. This polysaccharide is produced mostly by green plants for energy storage, e.g., peeled potato.