Characteristics of a Virus
- Infectious Nature:
Viruses are infectious agents that can only replicate within living cells of organisms. They cannot grow or reproduce on their own and rely on a host organism to multiply.
- Genetic Material:
Viruses contain genetic material, either DNA or RNA, surrounded by a protein coat called a capsid. Some viruses also have an outer lipid envelope.
- Size:
Viruses are much smaller than bacteria and other microorganisms, ranging in size from 20 to 300 nanometers.
- Specificity:
Each virus has a specific host range and can only infect certain types of cells or organisms. This specificity is due to the interaction between viral surface proteins and host cell receptors.
- Replication:
Once inside a host cell, a virus hijacks the cell's machinery to replicate its genetic material and produce more viral particles. This process often leads to cell damage or death.
- Evolution:
Viruses can evolve rapidly through mutations and genetic recombination, leading to the emergence of new viral strains that may be more infectious or resistant to treatment.
- Pathogenicity:
Some viruses cause diseases in humans, animals, and plants by disrupting normal cellular functions and triggering immune responses. Common viral infections include the flu, HIV, and COVID-19.
- Transmission:
Viruses can spread through various means, such as respiratory droplets, contaminated surfaces, or vectors like mosquitoes. Preventive measures like vaccination and hygiene practices are essential to control viral spread.
Overall, viruses are unique infectious agents that exhibit distinct characteristics which enable them to survive, replicate, and cause diseases in their host organisms.

Contain DNA and RNA