NEET BIOLOGY

Detailed explanation-1: -Viral Structure. In the simpler viruses the virion consists of a single molecule of nucleic acid surrounded by a protein coat, the capsid; the capsid and its enclosed nucleic acid together constitute the nucleocapsid.

Detailed explanation-2: -Viruses are bundles of genetic material wrapped in a protein coat that can infect living things. Viruses cause damage by hijacking a host cell’s machinery to make copies of themselves, often disrupting normal cell function.

Detailed explanation-3: -However, all virus particles have a protein coat that surrounds and protects a nucleic acid genome. This protein coat is called a capsid, and the instructions for making the protein subunits of the capsid are encoded in the nucleic acid genome of the virus.

Detailed explanation-4: -Most viruses have icosahedral or helical capsid structure, although a few have complex virion architecture. An icosahedron is a geometric shape with 20 sides, each composed of an equilateral triangle, and icosahedral viruses increase the number of structural units in each face to expand capsid size.

Detailed explanation-5: -The simplest virions consist of two basic components: nucleic acid (single-or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.