What is a virus?

A virus is a microscopic infectious agent that can only replicate inside the living cells of an organism. They can infect all forms of life, from animals and plants to bacteria and archaea. While some viruses can cause mild illnesses like the common cold, others can lead to more severe diseases such as COVID-19, HIV, and Ebola.

Structure of a virus

A typical virus consists of genetic material, either DNA or RNA, surrounded by a protective protein coat called a capsid. Some viruses also have an outer envelope made of lipids. The genetic material carries the instructions for making new viruses once it enters a host cell.

How viruses infect cells

Viruses infect a host cell by binding to specific receptors on the cell surface. Once attached, the virus injects its genetic material into the cell. The viral genetic material then takes over the host cell's machinery to replicate itself, producing new viruses that can infect other cells.

Impact of viruses on health

Viruses can have a significant impact on human health, causing a wide range of diseases. Vaccines are available for some viral infections, helping prevent outbreaks and protect populations. Understanding the biology of viruses is crucial for developing effective treatments and preventive measures against viral diseases.