NBME Biochemistry Exam Questions and Answers

NBME Biochemistry Exam Questions
and Answers

glycolysis ii- iiAnswers ii-Key iienzyme iiis iiphosphofructokinase-1 ii(PFK-1). iiRegulated iiby:
ii+AMP, ii+fructose-2-6-BP, ii-ATP, ii-citrate.


gluconeogenesis ii- iiAnswers ii-Key iienzyme iiis iifructose ii1,6 iibisphosphatase ii(converts
iithe iiPFK-1 iiglycolysis iistep iiin iiopposite iidirection). iiRegulated iiby: ii-AMP, ii-fructose-2-
6-BP, ii+ATP, ii+acetyl-CoA.

TCA iicycle ii- iiAnswers ii-Key iienzyme iiis iiisocitrate iidehydrogenase. iiRegulated iiby:
ii+ADP, ii-ATP, ii-NADH


glycogen iisynthesis ii- iiAnswers ii-Key iienzyme iiis iiglycogen iisynthase. iiIt iitransfers
iiglucose iiresidues iifrom iiUDP-Glucose iito iinonreducing iiend iiof iiglycogen iiprimer.
iiRegulated iiby: ii+G6P, ii+insulin, ii+cortisol, ii-Epi, ii-glucagon ii(by iicausing
iiphosphorylation iiby iiPKA).


glycogenolysis ii- iiAnswers ii-Key iienzyme iiis iiglycogen iiphosphorylase, iiwhich iiis
iiACTIVE iiwhen iiphosphorylated iiby iiPKA. iiIt iicleaves iiglucose iiresidues iifrom iinon-
reducing iiends iiof iiglycogen iichains iito iimake iiG1P. iiRegulated iiby: ii+Epi, ii+glucagon,
ii+AMP, ii+CALCIUM, ii-G6P, ii-insulin, ii-ATP.


HMP iishunt ii- iiAnswers ii-Key iienzyme iiis iiglucose-6-phosphate iidehydrogenase
ii(G6PD). iiRegulated iiby: ii+NADP+, ii-NADPH. iiOccurs iiin iicyto iiof iimammary iiglands,
iiliver, iiadrenal, iiRBCs. iiNo iiATP iiused iior iiproduced.


de iinovo iipyrimidine iisynthesis ii- iiAnswers ii-Key iienzyme iiis iicarbamoyl iiphosphate
iisynthetase iiII ii(CAD iicomplex). iiRegulated iiby: ii+ATP, ii-UTP.


de iinovo iipurine iisynthesis ii- iiAnswers ii-Key iienzyme iiis iiPRPP iiamidotransferase.
iiRegulated iiby: ii-AMP, ii-IMP, ii-GMP, ii+PRPP.


urea iicycle ii- iiAnswers ii-Key iienzyme iiis iicarbamoyl iiphosphate iisynthetase iiI.
iiRegulated iiby: ii+N-acetylglutamate ii(which iiis iithe iiCPS1 iicofactor)


fatty iiacid iisynthesis ii- iiAnswers ii-Key iienzyme iiis iiacetyl-coA iicarboxylase. iiRegulated
iiby: ii+insulin, ii+citrate, ii-glucagon, ii-palmitoyl iiCoA.


fatty iiacid iioxidation ii- iiAnswers ii-Key iienzyme iiis iicarnitine iiacyltransferase iiI.
iiRegulated iiby: ii-Malonyl iiCoA.