Carbohydrates  Made mostly of carbon, hydrogen and oxygen  Small carbohydrates are called monosaccharides, single or simple sugars.  Most common monosaccharide is glucose: C 6 H 12 O 6  In cells, glucose looks like: C 6 C5 C4 C1.ummary of Proteins  Subunits are amino acids  Amino acids are joined by condensation reactions that form peptide bonds  The amino acid sequence is a protein’s primary structure.