NEET BIOLOGY

Detailed explanation-1: -Prior to entry, a virus must attach to a host cell. Attachment is achieved when specific proteins on the viral capsid or viral envelope bind to specific proteins called receptor proteins on the cell membrane of the target cell.

Detailed explanation-2: -Viruses are typically described as obligate intracellular parasites, acellular infectious agents that require the presence of a host cell in order to multiply. Viruses that have been found to infect all types of cells – humans, animals, plants, bacteria, yeast, archaea, protozoa…

Detailed explanation-3: -A virus is an infectious agent that can only replicate within a host organism. Viruses can infect a variety of living organisms, including bacteria, plants, and animals.

Detailed explanation-4: -Viruses initially stick to cell membranes through interactions unrelated to fusion proteins. The virus surfs along the fluid surface of the cell and eventually the viral fusion proteins bind to receptor molecules on the cell membrane (4).