Now let's review what amino acids are. Amino acids are the building blocks of proteins. Everything your DNA codes for is protein, so your DNA codes for amino acids. There are only 20 amino acids total, but each one has a generalized structure. Each of the 20 different amino acids shares the amino group, the carboxyl group, the Hydrogen atom, and the central Carbon atom.
R is simply a symbol for the side group.
There is the specialized apparatus for making proteins called the ribosome . There are many ribosomes in the cytoplasm of a cell, and all the ribosomes are made of a small subunit and a large subunit . Once the mRNA message is in place and protein synthesis is ready to begin, the two subunits close again so that the mRNA is now in between the two subunits. Remember, the mRNA is now held within the two subunits of the ribosome and is relatively immobile. Every tRNA molecule has its own set of three bases which is called an anticodon.