Biology Questions

The nucleotides that are present in DNA molecule are 4. They are Thymine (T), Guanine (G), Adenine (A) and Cytosine (C).

Here in this Adenine pairs with Thymine (A - T) and Cytosine pairs with Guanine (C - G).

Enzymes play an essential role in each living cell of our body. Enzymes are globular proteins that control biological reactions. These are of two types.

1. Intracellular enzymes

2. Extracellular enzymes

Intracellular enzymes are found inside the cell.

Extracellular enzymes act outside the cell.

Enzymes are produced by exocrine glands.

Digestive enzymes of diverse specificities are secreted by the salivary glands, stomach, pancreas, and the small intestine.

S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease.