Metabolism Flashcards
a) What is necessary for oxidative phosphorylation in mitochondrial bioenergetics
b) What is both a substrate and an allosteric inhibitor of PFK
c) What activates triacylglycerol hydrolysis
d) What is able to be converted to glucose
e) What sort of reaction is the citric acid cycle CAC
a) An ATP synthase and a proton pumping system located in the same sealed membrane are necessary
b) ATP
c) Activated by hormones that use cyclic AMP as a second messenger
d) Both glycerol and fatty acids released from triacylglycerols can be converted to glucose
e) It is exclusively catabolic, and no intermediates can be used for biosynthesis
a) What does the oxidation of one molecule of succinate by (1/2)O2 result in
b) How is PMF established
c) What is the reaction ADP + Pi → ATP + H2O catalysed by, and what drives the reaction
d) What is the uptake of phosphate by the matrix driven by
e) In rapidly contracting muscle, what is formed overall when one molecule of glucose is converted to two lactate molecules
a) Results in transfer of 6 protons across the inner mitochondrial membrane (IMM)
b) Established by pumping protons across the IMM from the matrix
c) Catalysed by the F1 ATP synthase, driven by the transport of 3 protons across the IMM
d) Driven by the pH gradient across the IMM
e) Overall formation of 2 ATP
a) What is activated by insulin and inhibited by glucagon
b) What does the biosynthesis of triacylglycerols require
c) Where does fatty acid biosynthesis occur
d) What is the first committed step in fatty acid biosynthesis
e) What does ammonia released from amino acids enter the urea cycle as
a) Acetyl-CoA carboxylase
b) Requires fatty acyl-CoA donors, not free fatty acids
c) Occurs in the cytoplasm, not in mitochondria
d) Involves carboxylation of acetyl-CoA
e) Enters urea cycle as carbamoyl phosphate
a) What is the precursor of ketone bodies
b) In mitochondrial bioenergetics, what does complex II require
c) In the citric acid cycle, what can calcium ions activate
d) When would you use inhibitors of phosphotyrosine phosphatases
e) What are the metabolic intermediates in the tricarboxylic acid cycle (8)
a) acetyl-CoA
b) Requires FAD to oxidise succinate
c) Can activate oxidation of acetyl-CoA by the cycle
d) Useful in the treatment of hyperglycaemia and diabetes
e) Citrate, Isocitrate, α-ketoglutarate, Succinyl-CoA, Succinate, Fumarate, Malate, Oxaloacetate
a) What can phosphorylate glycogen synthase and so lower its activity
b) What does pyruvate conversion in liver start with
c) What is the main initial source of acetyl-CoA
d) Where does the carboxylation of acetyl-CoA to malonyl-CoA occur
e) What reducing coenzyme is required for fatty acid biosynthesis
a) Protein kinase A
b) Starts with its carboxylation to oxaloacetate
c) Pyruvate dehydrogenase
d) Occurs in the cytoplasm
e) NADPH
a) If antimycin was added to mitochondria that were using O2 to oxidise NADH, what would happen to cytochrome c and FMN in complex III
b) Where do the H+ ions enter from when driving the synthesis of ATP from ADP and Pi in the mitochondrial matrix
c) Give a metabolic conversion that doesn’t involve cleavage of a phosphoanhydride bond
d) What is alanine a precursor for
e) What is alanine a major carrier of
a) Cytochrome c becomes more oxidised and FMN becomes more reduced
b) H+ ions from the intermembrane space
c) β-oxidation of fatty acyl-CoA molecules
d) Gluconeogenesis
e) Major carrier of nitrogen from muscle to the liver
a) How are ammonium ions made from glutamate
b) What sort of enzymes does the urea cycle involve
c) What activates pyruvate carboxylase
d) What happens to Gibbs free energy across the overall pathway of glycolysis
e) When is the glycolytic pathway especially important
a) Glutamate is oxidatively deaminated to yield ammonium ions
b) Involves cytoplasmic and mitochondrial enzymes
c) Acetyl-CoA
d) There is a decrease in Gibbs free energy
e) For energy production in fast twitch muscle during sprinting
a) What can Ca2+ activate in the citric acid cycle
b) What inhibits isocitrate dehydrogenase
c) What happens to the activity of pyruvate dehydrogenase following its phosphorylation
d) What reduces the activity of α-ketoglutarate dehydrogenase
e) What complex of the redox transport chain in mitochondria is part of the citric acid cycle
a) Activates both pyruvate dehydrogenase and α-ketoglutarate dehydrogenase
b) Inhibited by a high NADH/NAD+ ratio in the cell
c) Activity is decreased
d) Activity is reduced by increased concentrations of succinyl-CoA
e) Complex II
a) What is cytochrome c loosely associated with
b) What complexes have iron-sulphur proteins
c) What is the reducing potential to drive electron transport derived from
d) What is a component with two haem prosthetic groups that recycles electrons in complex III
e) What is an electron shuttle that does not diffuse within the inner mitochondrial membrane
a) Loosely associated with the outer surface of the mitochondria
b) Complexes I, II and III
c) Derived from NADH and FADH2 production
d) Cytochrome b
e) Cytochrome c
a) What is a cofactor that passes reducing equivalents to iron-sulphur centres in complex I
b) What is an enzyme that is needed for long chain fatty acids to be oxidised by mitochondrial β-oxidation and is inhibited by malonyl-CoA
c) What enzyme is needed for complete oxidation of glucose and for biosynthesis of fatty acids from glucose, which is inhibited by acetyl-CoA and activated by insulin
d) What enzyme is needed exclusively for fatty acid biosynthesis that is activated by insulin and inhibited by glucagon
e) What substrate is needed for the synthesis of cyclic 3’5’-AMP
a) NADH
b) Carnitine acyltransferase
c) Pyruvate dehydrogenase
d) Acetyl-CoA carboxylase
e) ATP
a) What substrate is required for the conversion of oxaloacetate to phosphoenolpyruvate
b) What substrate is required for the elongation of glycogen chains
c) What inhibits the transfer of electrons from FeS to ubiquinone
d) What has succinate dehydrogenase activity
e) What passes electrons to cytochrome a
a) GTP
b) UDP-glucose
c) Rotenone
d) Complex II
e) Cytochrome c
a) What biochemical process is inhibited by chloramphenicol
b) What is a respiratory uncoupler
c) What blocks aminoacyl-tRNA binding to the ribosome
d) What has the capacity to pump H+ across the inner mitochondrial membrane
e) Which substance specifically inhibits complex III in the respiratory chain
a) Translation
b) Dinitrophenol
c) Tetracycline
d) NADH-Q reductase complex (complex I)
e) Antimycin A
a) Which substance is taken up by mitochondria as a consequence of the pumping of H+ ions
b) What is the most effective inhibitor of ATP-sensitive potassium channels in the plasma membrane of pancreatic β-cells
c) What is the most effective inhibitor of cyclic AMP phosphodiesterase
d) What is the most effective inhibitor of protein synthesis in prokaryotes
e) What is the number of acetyl-CoA molecules produced by the β-oxidation of steric acid (a saturated fatty acid containing 18 carbon atoms)
a) Phosphate
b) Sulphonylureas (eg glibenclamide)
c) Methylxanthines (eg caffeine)
d) Tetracycline
e) 9
a) What is the number of carbon atoms in one molecule of citric acid
b) What is the net number of molecules of ATP formed when a glucose residue is removed from glycogen by phosphorylase and converted to lactate
c) What enzyme of glycolysis is inhibited by citrate as well as ATP
d) What enzyme present in the mitochondrial matrix is inhibited by phosphorylation and whose activity rises in response to insulin
e) What enzyme’s activity in the liver is lowered in response to glucagon and is inhibited by alanine
a) 6
b) 3
c) Phosphofructokinase
d) Pyruvate dehydrogenase
e) Pyruvate kinase
a) What is an allosteric modulator that regulates the balance between glycolysis and gluconeogenesis acting at phosphofructokinase-1
b) What is an intermediate in both the citric acid cycle and gluconeogenesis
c) What hormone promotes glucose uptake by brain cells
a) Fructose-2,6-bisphosphate
b) Oxaloacetate
c) Adrenaline
