NEET BIOLOGY

Detailed explanation-1: -Viruses can infect only certain species of hosts and only certain cells within that host. The molecular basis for this specificity is that a particular surface molecule, known as the viral receptor, must be found on the host cell surface for the virus to attach.

Detailed explanation-2: -Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are infectious agents with both living and nonliving characteristics.

Detailed explanation-3: -Because they can’t reproduce by themselves (without a host), viruses are not considered living. Nor do viruses have cells: they’re very small, much smaller than the cells of living things, and are basically just packages of nucleic acid and protein.

Detailed explanation-4: -All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.

Detailed explanation-5: -Which of the following statements about viruses is FALSE?-Viruses contain DNA or RNA but never both.