Leu, phe) ---> ~ of the protein is hydrophobic in character. [ carbohydrates ] fructose is most common ketose, glucose is most common aldose. [ aldehyde + alcohol = hemiacetal ] added the alcohol across the double bond to create four single bonds hemiacetals are unstable intermediates usually, but they can be formed as more stable cyclical hemiacetal. 5-membered heterocyclic (because an oxygen is in the ring) ring glucose can form pyranose and furanose rings furan doesn"t have the hydroxy groups found in the sugar furanose same goes for pyran and pyranose. [ some forms are more abundant than others ] Alpha-d-glcopyranose and beta-d-glucopyranose are the most stable because the hydroxyl groups are spread out to avoid steric hindrance. Alpha is less stable because the axial and merdian hydroxyl groups are crowding each other slightly, whereas in beta they are all very far apart in starches, it"s always alpha-d-glucopyranose because of the 1,4 linkage.