BIOMOLECULES AND ENZYMES

Detailed explanation-1: -A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself. Often, a virus ends up killing the host cell in the process, causing damage to the host organism. Well-known examples of viruses causing human disease include AIDS, COVID-19, measles and smallpox.

Detailed explanation-2: -A virus needs a living cell in order to reproduce. The living cell in which the virus reproduces is called a host cell.

Detailed explanation-3: -Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane.

Detailed explanation-4: -Since viruses are intracellular parasites, they rely on their host cells for the energy, macromolecular synthesis machinery and the work benches for genome replication and particle assembly.