Each question has but one correct or most appropriate answer. Darken a single space for each question of questions 1 through 28 on the computer answer sheet. All erasures must be thorough. Stray marks on the answer sheet could cause errors in grading. Lipid bilayers are highly impermeable to ions and most polar molecules.
Hydrophobic interactions are the major driving force for the formation of lipid bilayers.
Saponifiable lipids are resistant to alkaline hydrolysis, whereas nonsaponifiable lipids are more complex and yield several compounds upon hydrolysis. Fatty acids are synthesized and degraded by different pathways, exemplifying the principle that synthetic and degradative pathways in biological systems are usually distinct. Phosphatidate is an intermediate in the synthesis of phosphoglycerides and triacylglycerols. Amino acids are made from intermediates of the citric acid cycle as well as from intermediates of glycolysis. The synthesis of fumarate by the urea cycle is important because it links the urea cycle and the citric acid cycle.