text: how many different types of the monomers of proteins are there? (biochemistry 3ques.? how many different types of the monomers of proteins are there?  what does an r group symbolize?  how many calories are in one gram of chos? 1g fats? 1g proteins?  the monomer of proteins are amino acid .right??s    please reply these questions -: o how many amino acids are there?  these are the "monomer" units, although they're not true monomers since they don't repeat much.    "r" symbolizes "other stuff" bonded to the peptide functionality.  different amino acids have different atoms for "r".    calories per gram depends on the specific material.  i would expect fats to contain the most, since they are mostly c and h, followed by carbohydrates, followed by proteins.  i could be wrong, though.