NEET BIOLOGY

Detailed explanation-1: -Viruses are small and relatively simple microbes that cannot grow outside of living cells, that is, they are obligate intracellular parasites (Figure 1).

Detailed explanation-2: -Viruses use the machinery of the host cells to reproduce. They do not have cell organelles such as Golgi complex, mitochondria, lysosomes, ribosomes etc. hence, they cannot reproduce or live separately. Therefore they are called obligatory intercellular parasites.

Detailed explanation-3: -A parasite is an organism that lives at the expense of another organism-the host.

Detailed explanation-4: -Parasites are different from bacteria or viruses because their cells share many features with human cells including a defined nucleus. Parasites are usually larger than bacteria, although some environmentally resistant forms are nearly as small.