Which amino acid side chain in a native protein molecule would most likely be in contact with water in a cell? Which are the most abundant lipids found within cell membranes? glycolipids phospholipids sphingolipids triglycerides (triacylglycerols) The lipid bilayer in the cell membrane is maintained by peptide bonds, acetal linkages, hydrogen bonds, hydrophobic interactions. Steroid hormones are synthesized from arachidonic acid, cholesterol, vitamin B12, glycolipids. An example of a fat-soluble vitamin is niacin, thiamine, vitamin C, vitamin E. The bonds that are broken when fats are digested are ester linkages, acetal linkages, amide linkages, hydrogen bonds. What is the difference between animal fats and vegetable oils? Fats have lower melting points than oils. Fats are straight chains; oils are branched. Fats have fewer double bonds per molecule than oils. Fats have less hydrogen than oils. The function of tRNA is to transfer an amino acid to the site of protein synthesis, a nucleotide to the site of DNA synthesis, the genetic message to the ribosome in protein synthesis, the DNA polymerase to the dividing DNA double helix during replication. Enzymes work by catalyzing an otherwise non-spontaneous reaction, raising the free energy of the reaction, lowering the activation energy of the reaction, raising the equilibrium constant of the reaction. 149. The term active site is most directly involved in discussion about how hormones function, molecules get through cell membranes, proteins are made, enzymes work. 150. Normal bile production facilitates the digestion of which type of nutrient? carbohydrates, proteins, fats, nucleic acids.