Coronavirus: You Need To Know Its Origin, Symptoms & Cases
CORONAVIRUS ITSELF Coronaviruses are a group of viruses that cause diseases in mammals and birds. ln humans, coronaviruses cause respiratory tract infections that are typically mild, such as the common cold, though rarer forms such as SARS, MERS and COVID-19 can be lethal. These viruses were originally transmitted between animals and people. SARS, for instance, was transmitted from civet cats to humans while MERS moved to humans from a type of camel. The genome size of coronaviruses ranges from approximately 27 to 34 kilobases, the largest known RNA viruses. Coronavirus genomes encode a protein called RNA-dependent RNA polymerase (RdRp), which allows the viral genome to be transcribed into new RNA copies using the host cell's machinery. The RdRp is the first protein to be made. Once the gene encoding the RdRp is translated, translation is stopped by a stop codon. This is known as a nested transcript. When the mRNA transcript only encodes on...