You need to be able to identify these four molecules if they are presented to you. Recognize the amino acid by the presence of nitrogen and the ‘R’ (variable) group. The fatty acids can have multiple [CH2] groups so look for it written in this shorthand way, or with the CH2′s written out in full. The ribose and glucose (both carbohydrate monomers, or monosaccharides) can be distinguished because the ribose only has 5 carbon atoms whereas the glucose has 6 carbon atoms.