Coronaviruses are a type of virus that can cause respiratory and other diseases in humans and animals. Some coronaviruses, like SARS and MERS, can be serious and spread from animals to humans. The recent SARS-CoV-2 virus, which causes COVID-19, is a type of betacoronavirus that can bind effectively to human cells. The spike protein on the virus targets a receptor called ACE2, which is involved in regulating blood pressure. The virus uses a protein called M to transport nutrients and release new virus particles. Understanding how these viruses work can help in developing treatments and vaccines.