Biomolecules and Enzymes

Telomerase is an enzyme that maintains telomeres (protective caps at the ends of chromosomes), which are associated with cellular aging. Spanish researchers discovered this enzyme's role in preventing cellular aging by maintaining telomere length. Ptyalin is a digestive enzyme, co-enzyme 23 is not a standard enzyme, and interferon 90 relates to immune response rather than aging.

Silk fibers are primarily composed of fibroin, a fibrous protein produced by silkworms. Fibrin is involved in blood clotting, casein is milk protein, making fibroin the correct silk protein.

Ferritin is the primary iron-storing protein in animals, plants, and bacteria. It stores iron in a soluble, non-toxic form. Alpha globulins and gamma globulins are blood proteins involved in other functions (like transport and immunity). Albumins are transport proteins.

Arginine, or L-arginine as it is called with its L-structure, is a semi-essential amino acid. Arginine is involved in many metabolic processes and is important in the treatment of heart diseases and high blood pressure. Arginine improves the circulation, strengthens the immune system and has a positive influence on male libido.

The folding of the polypeptide chain is stabilised by weak, non-covalent interactions.

These proteins are linked with various metals. Examples: casein, collagen, ceruloplasmin, etc.

It provides resistance to our body and inhibits the growth of hair, nails etc.

Deamination is the removal of an amino group from an amino acid or other compound.

 Cytochrome c is a highly soluble protein.The heme group of cytochrome c accepts electrons from the bc1 complex and transfers electrons to the complex IV. Cytochrome c is also involved in initiation of apoptosis.

The codon GCG (Glycine-Cytosine-Guanine) codes for the amino acid Alanine. This is a standard codon in the genetic code. Glutamine is coded by CAA/CAG, Serine by multiple codons including UCU/UCC/UCA/UCG/AGU/AGC, and Proline by CCU/CCC/CCA/CCG.

Transamination is the process where an amino group is transferred from an amino acid to a keto acid, forming a new amino acid. This is a key step in amino acid metabolism where nitrogen is ultimately converted to urea in the liver. Option B correctly identifies conversion of ammonia to urea (urea cycle), while C describes deamination (removal, not transfer). Option A is the reverse of what actually happens.

Enzymes are biological catalysts that speed up chemical reactions without being consumed. While most enzymes are proteins (option A), they are fundamentally defined by their catalytic function, not their chemical composition.

This option is correct.

Option C states 'Tonic acid: Leather' which is incorrect. The correct pairing should be 'Tannic acid: Leather' because tannic acid (or tannins) are used in leather tanning to preserve and soften animal hides. 'Tonic acid' appears to be a typo or error - there is no such compound used in leather processing. Options A and B (Acetic acid: Vinegar, Amino acid: Proteins) are correct pairings.

Keratin is a fibrous structural protein that is the key structural material for making up hair, nails, horns, feathers, and the outer layer of human skin. It is not a hormone - hormones are chemical signaling molecules. Keratin provides mechanical protection and is responsible for the strength and toughness of these structures.