Health & Medicine

Ribonucleic Acid

Ribonucleic Acid (RNA), genetic material of certain viruses (RNA viruses) and, in cellular organisms, the molecule that directs the middle steps of protein production. In RNA viruses, the RNA directs two processes—protein synthesis (production of the virus's protein coat) and replication (the process by which RNA copies itself). In cellular organisms, another type of genetic material, called deoxyribonucleic acid (DNA), carries the information that determines protein structure. But DNA cannot act alone and relies upon RNA to transfer this crucial information during protein synthesis (production of the proteins needed by the cell for its activities and development).

Like DNA, RNA consists of a chain of chemical compounds called nucleotides. Each nucleotide is made up of a sugar molecule called ribose, a phosphate group, and one of four different nitrogen-containing compounds called bases. The four bases are adenine, guanine, uracil, and cytosine. These components are joined together in the same manner as in a deoxyribonucleic acid (DNA) molecule. RNA differs chemically from DNA in two ways: The RNA sugar molecule contains an oxygen atom not found in DNA, and RNA contains the base uracil in the place of the base thymine in DNA.