These molecules of tRNA move up close to the mRNA and sequentially add the appropriate amino acid to the growing string of amino acids. Review Let's review. The major polymers of molecular biology consist of physical entitities that are similar to the conceptual strings of computer science. There are two classes of polymers, informational and operational. DNA and RNA are strings with an alphabet of four nucleotides.
Proteins are strings with an alphabet of twenty amino acids.
DNA usually is composed of two strings, each complementary to the other but running in opposite directions. During replication, the two polymers of DNA separate, and two new polymers are synthesized. And you may recall that proteins are called operational polymers. The key to answering these questions is in proteins. And the key to understanding protein is their structure.