virusessuch

Viruses are microscopic infectious agents that replicate only inside the living cells of other organisms. They are much smaller than bacteria, being about 100 times smaller. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. Some viruses, like bacteriophages, infect only bacteria. Viruses were discovered in the late 19th century and were named "virusessuch" due to their small size and ability to pass through filters that trapped bacteria.

The structure of a virus is relatively simple. It consists of genetic material, either DNA or RNA, enclosed in a protein coat called a capsid. Some viruses also have an outer lipid envelope derived from the host cell membrane. Viruses lack the machinery for self-replication and rely entirely on host cells to reproduce. They inject their genetic material into a host cell, hijacking the cell's machinery to produce more viral particles. These new viruses are then released from the host cell, often destroying it in the process, and go on to infect other cells.

Viruses can cause a wide range of diseases in humans, animals, and plants. Examples include the common cold, influenza, COVID-19, measles, and AIDS. Transmission routes vary widely, including airborne droplets, direct contact, contaminated food or water, and insect vectors. The study of viruses is called virology. While many viruses cause disease, some are harmless or even beneficial, playing roles in ecosystems or being used in biotechnology. Research into antiviral drugs and vaccines is ongoing to combat viral infections.