Answer:
A virus is a microscopic infectious agent that can only replicate inside the living cells of organisms. It is composed of genetic material, either DNA or RNA, surrounded by a protein coat called a capsid. The capsid is made up of protein subunits called capsomeres, and its shape can be helical, icosahedral, or complex. Some viruses have an outer envelope made up of a lipid membrane that is derived from the host cell membrane and studded with proteins called spikes.
The genetic material of the virus is either single-stranded or double-stranded and can be either linear or circular. Some viruses have additional structures such as enzymes or additional protein layers.
The structure of a virus enables it to invade host cells and take control of the cellular machinery to replicate itself. The spikes on the surface of some viruses allow them to bind to specific receptors on host cells, while the capsid protects the genetic material from being destroyed by enzymes and the host's immune system. Once inside the host cell, the virus hijacks the cellular machinery to replicate itself, leading to the spread of the infection.
Step-by-step explanation: