USMLE Biochemistry Exam Questions and Correct Answers

USMLE Biochemistry Exam Questions and Correct Answers What is the rate-limiting enzyme of glycolysis? - ANSWER phosphofructokinase-1 (PFK-1) What is the rate-limiting enzyme of gluconeogenesis? - ANSWER fructose-1,6-bisphosphatase What is the rate-limiting enzyme of the TCA cycle? - ANSWER isocitrate dehydrogenase What is the rate-limiting enzyme of glycogen synthesis? - ANSWER glycogen synthase What is the rate-limiting enzyme of glycogenolysis? - ANSWER glycogen phosphorylase What is the rate-limiting enzyme of the HMP shunt? - ANSWER glucose-6-phosphate dehydrogenase (G6PD) What is the rate-limiting enzyme of de novo pyrimidine synthesis? - ANSWER carbamoyl phosphate synthetase II (CPS II) What is the rate-limiting enzyme of de novo purine synthesis? - ANSWER glutamine-PRPP amidotransferase What is the rate-limiting enzyme of the urea cycle? - ANSWER carbamoyl phosphate synthetase I (CPS I) What is the rate-limiting enzyme of fatty acid synthesis? - ANSWER acetyl-CoA carboxylase