Middle back pain is any type of pain or discomfort in the area between your upper and lower back. Health care professionals refer to this area as the lower thoracic area or lower thoracic spine. The upper thoracic area or upper thoracic spine makes up part of the upper back.
Amino Acids. Amino acids are the monomers of proteins. They have a positively-charged amino group on one side and a negatively-charged carboxyl group on the other. Attached to the central carbon is a variable group called the 'R' group. This group is different for each amino acid. There are 20 amino acids in human cells.
Proteins are polymers. The monomers which make up proteins are called amino acids.. Amino acids consist of an amino group (NH3), carboxyl group (COOH), a hydrogen, and an r group (any carbon chain or hydrogen). The variation in r groups allows for the diversity of amino acids, and thus the variety of proteins.