MCB 450 EXAM 4 PRACTICE QUESTIONS
AND ANSWERS 2026 A+ GUARANTEED
1. Fatty acyl CoA Synthetase - ANSWER -activates fatty acids by attachment
to CoA
2. -product is referred to as fatty acyl-CoA
3. CPT1 - ANSWER -transporting fatty acids into the mitochondria
-Swaps CoA for carnitine on Fatty acyl-CoA
4. CACT - ANSWER Translocase transporting fatty acyl-carnitine into
mitochondria.
5. CPTII - ANSWER Converts carnitine bound FA back to fatty acyl-CoA for
beta oxidation
6. Propionyl CoA - ANSWER -Produced during the oxidation of odd-chain
fatty acids
- Adds with ATP, biotin, Coenzyme B12, and enzymes to form
Succinyl CoA -> TCA
7. HMG CoA Lyase - ANSWER breaks down HMG CoA into acetoacetate to
ketone body synthesis
8. Alcohol Dehydrogenase - ANSWER -acetaldehyde to ethanol and vise versa
-regenerates NAD+ for glycolysis
-Main one is ADH1
9. Pyruvate Decarboxylase - ANSWER -pyruvate to acetaldehyde from alcohol
fermentation
-uses TPP like E1
10.Aldehyde Dehydrogenase - ANSWER Enzyme that metabolizes
acetaldehyde to acetate
1
,11.Acetyl CoA Synthetase - ANSWER combines acetate, ATP, and coenzyme
A to make acetyl-CoA
12.Glycerol - ANSWER -Substrate for gluconeogenesis
- Glycerol -> Glycerol 3P -> DHAP
- Can produce TG with FA
13.Glycerol Kinase - ANSWER glycerol to glycerol 3-phosphate
14.Lactate - ANSWER -Can convert to pyruvate in gluconeogenesis
- Created from muscles working out and can be sent to the liver to be
turned into glucose
-Pyruvate can be converted into lactate (not favorable)
15.Amino Acids (AA) - ANSWER -Can be made into pyruvate or join the TCA
cycle for gluconeogenesis
-From the degradation of muscle
-AA metabolism generates urea
-Forms adducts with acetaldehyde
16.Aminotransferase and PLP - ANSWER Turns amino acids into pyruvate
17.Aldolase - ANSWER combines DHAP and glyceraldehyde 3P into Fructose
1,6 BP
18.PDC - ANSWER -Converts pyruvate into Acetyl-CoA and makes NADH
during glycolysis
-Inactive (phosphorylated) during gluconeogenesis as Acetyl-CoA and
NADH levels are high and are inhibitory
-Has substrate channeling: passes substrate/intermediates between enzymes
and never leave the complex
19.E1 - ANSWER -Enzyme: Pyruvate dehydrogenase
-Thiamine Pyrophosphate (TPP) prosthetic group
-Turns pyruvate into hydroxyethyl TPP
20.E2 - ANSWER -Enzyme: Dihydrolipoyl transacetylase
-Lipoic acid prosthetic group
-dihydrolipoamide is created
21.E3 - ANSWER -Enzyme: Dihydrolipoyl dehydrogenase
2
, -FAD prosthetic group
-Transfers e- to make NADH
22.Pyruvate Carboxylase - ANSWER -converts pyruvate to oxaloacetate
-bypasses pyruvate kinase together with pyruvate carboxylase
-Has biotin as a cofactor
-Homo-tetramer
23.Phosphoenolpyruvate carboxykinase (PEPCK) - ANSWER -converts
oxaloacetate (OAA) to phosphoenolpyruvate (PEP), which requires GTP
-bypasses pyruvate kinase together with pyruvate carboxylase
-Regulated at the transcription level
-Contains an Arg finger and Mn2+ that e- withdraws
24.Biotin - ANSWER -Cofactor that is covalently attached to Pyruvate
Carboxylase
-Reacts with CO2 in site 1 and carries it to site 2 to add to pyruvate -> OAA
25.Pyruvate Kinase - ANSWER -Inactivated (phosphorylated) by glucagon and
PKA, so PEP doesn't go to pyruvate in gluconeogenesis
-Activated by Insulin signaling PP
26.Fructose 1,6-bisphosphatase - ANSWER fructose 1,6-bisphosphate to
fructose 6-phosphate
27.Fructose 2,6 Bisphosphate - ANSWER -F2,6BP inhibits of FBP-1 which
prevents F 1,6BP from becoming F6P
-Inhibiting powers are reduced by a high glucagon/insulin ratio and increase
gluconeogenesis
28.Glucose 6 Phosphatase - ANSWER Enzyme converting glucose-6-phosphate
to glucose.
29.Von Gierke's Disease - ANSWER -glycogen storage disease
-Glucose 6-phosphatase deficiency
-hypoglycemia since glucose cannot go into the blood
30.Fox01 - ANSWER -Prevents uptake of glucose
-Can be inhibited by insulin, so glucose can be brought in from the blood
-T2D: insulin fails to inhibit so glucose stays in blood = hyperglycemia
3
, 31.Arsenite (mercury) - ANSWER -Inhibits PDC by inactivating E2
32.Acetyl-CoA sources - ANSWER -FA palmitate
-Ketone bodies
-Pyruvate
-Ethanol
33.Citrate Synthase - ANSWER -Oxaloacetate + Acetyl CoA --> Citrate
-aldol condensation
34.Aconitase - ANSWER -citrate to isocitrate by isomerization
-Starts via deprotonation
35.Isocitrate Dehydrogenase - ANSWER -isocitrate to alpha-ketoglutarate
36.-Makes first NADH and releases first CO2
37.a-ketoglutarate dehydrogenase - ANSWER -a-ketoglutarate to succinyl-CoA
-3 enzyme complex like pDC
-second NADH and CO2
38.Succinyl CoA Synthetase - ANSWER -succinyl-CoA to succinate and GTP
39.Succinate Dehydrogenase - ANSWER -succinate to fumarate
-FAD is reduced to FADH2 (2 e- 2H)
-Complex III ETC
40.Fumarase - ANSWER fumarate to malate
41.Malate Dehydrogenase - ANSWER -malate to oxaloacetate
-Third and final NADH and CO2
-OAA is depleted by citrate synthase rxn to make citrate
42.Cholesterol - ANSWER -amphipathic lipid w/ hydrophilic OH and
hydrophobic tail
-B face is methyls that will associate with proteins and the a face associates
with acyl chains
-Moderate fluidity
4
AND ANSWERS 2026 A+ GUARANTEED
1. Fatty acyl CoA Synthetase - ANSWER -activates fatty acids by attachment
to CoA
2. -product is referred to as fatty acyl-CoA
3. CPT1 - ANSWER -transporting fatty acids into the mitochondria
-Swaps CoA for carnitine on Fatty acyl-CoA
4. CACT - ANSWER Translocase transporting fatty acyl-carnitine into
mitochondria.
5. CPTII - ANSWER Converts carnitine bound FA back to fatty acyl-CoA for
beta oxidation
6. Propionyl CoA - ANSWER -Produced during the oxidation of odd-chain
fatty acids
- Adds with ATP, biotin, Coenzyme B12, and enzymes to form
Succinyl CoA -> TCA
7. HMG CoA Lyase - ANSWER breaks down HMG CoA into acetoacetate to
ketone body synthesis
8. Alcohol Dehydrogenase - ANSWER -acetaldehyde to ethanol and vise versa
-regenerates NAD+ for glycolysis
-Main one is ADH1
9. Pyruvate Decarboxylase - ANSWER -pyruvate to acetaldehyde from alcohol
fermentation
-uses TPP like E1
10.Aldehyde Dehydrogenase - ANSWER Enzyme that metabolizes
acetaldehyde to acetate
1
,11.Acetyl CoA Synthetase - ANSWER combines acetate, ATP, and coenzyme
A to make acetyl-CoA
12.Glycerol - ANSWER -Substrate for gluconeogenesis
- Glycerol -> Glycerol 3P -> DHAP
- Can produce TG with FA
13.Glycerol Kinase - ANSWER glycerol to glycerol 3-phosphate
14.Lactate - ANSWER -Can convert to pyruvate in gluconeogenesis
- Created from muscles working out and can be sent to the liver to be
turned into glucose
-Pyruvate can be converted into lactate (not favorable)
15.Amino Acids (AA) - ANSWER -Can be made into pyruvate or join the TCA
cycle for gluconeogenesis
-From the degradation of muscle
-AA metabolism generates urea
-Forms adducts with acetaldehyde
16.Aminotransferase and PLP - ANSWER Turns amino acids into pyruvate
17.Aldolase - ANSWER combines DHAP and glyceraldehyde 3P into Fructose
1,6 BP
18.PDC - ANSWER -Converts pyruvate into Acetyl-CoA and makes NADH
during glycolysis
-Inactive (phosphorylated) during gluconeogenesis as Acetyl-CoA and
NADH levels are high and are inhibitory
-Has substrate channeling: passes substrate/intermediates between enzymes
and never leave the complex
19.E1 - ANSWER -Enzyme: Pyruvate dehydrogenase
-Thiamine Pyrophosphate (TPP) prosthetic group
-Turns pyruvate into hydroxyethyl TPP
20.E2 - ANSWER -Enzyme: Dihydrolipoyl transacetylase
-Lipoic acid prosthetic group
-dihydrolipoamide is created
21.E3 - ANSWER -Enzyme: Dihydrolipoyl dehydrogenase
2
, -FAD prosthetic group
-Transfers e- to make NADH
22.Pyruvate Carboxylase - ANSWER -converts pyruvate to oxaloacetate
-bypasses pyruvate kinase together with pyruvate carboxylase
-Has biotin as a cofactor
-Homo-tetramer
23.Phosphoenolpyruvate carboxykinase (PEPCK) - ANSWER -converts
oxaloacetate (OAA) to phosphoenolpyruvate (PEP), which requires GTP
-bypasses pyruvate kinase together with pyruvate carboxylase
-Regulated at the transcription level
-Contains an Arg finger and Mn2+ that e- withdraws
24.Biotin - ANSWER -Cofactor that is covalently attached to Pyruvate
Carboxylase
-Reacts with CO2 in site 1 and carries it to site 2 to add to pyruvate -> OAA
25.Pyruvate Kinase - ANSWER -Inactivated (phosphorylated) by glucagon and
PKA, so PEP doesn't go to pyruvate in gluconeogenesis
-Activated by Insulin signaling PP
26.Fructose 1,6-bisphosphatase - ANSWER fructose 1,6-bisphosphate to
fructose 6-phosphate
27.Fructose 2,6 Bisphosphate - ANSWER -F2,6BP inhibits of FBP-1 which
prevents F 1,6BP from becoming F6P
-Inhibiting powers are reduced by a high glucagon/insulin ratio and increase
gluconeogenesis
28.Glucose 6 Phosphatase - ANSWER Enzyme converting glucose-6-phosphate
to glucose.
29.Von Gierke's Disease - ANSWER -glycogen storage disease
-Glucose 6-phosphatase deficiency
-hypoglycemia since glucose cannot go into the blood
30.Fox01 - ANSWER -Prevents uptake of glucose
-Can be inhibited by insulin, so glucose can be brought in from the blood
-T2D: insulin fails to inhibit so glucose stays in blood = hyperglycemia
3
, 31.Arsenite (mercury) - ANSWER -Inhibits PDC by inactivating E2
32.Acetyl-CoA sources - ANSWER -FA palmitate
-Ketone bodies
-Pyruvate
-Ethanol
33.Citrate Synthase - ANSWER -Oxaloacetate + Acetyl CoA --> Citrate
-aldol condensation
34.Aconitase - ANSWER -citrate to isocitrate by isomerization
-Starts via deprotonation
35.Isocitrate Dehydrogenase - ANSWER -isocitrate to alpha-ketoglutarate
36.-Makes first NADH and releases first CO2
37.a-ketoglutarate dehydrogenase - ANSWER -a-ketoglutarate to succinyl-CoA
-3 enzyme complex like pDC
-second NADH and CO2
38.Succinyl CoA Synthetase - ANSWER -succinyl-CoA to succinate and GTP
39.Succinate Dehydrogenase - ANSWER -succinate to fumarate
-FAD is reduced to FADH2 (2 e- 2H)
-Complex III ETC
40.Fumarase - ANSWER fumarate to malate
41.Malate Dehydrogenase - ANSWER -malate to oxaloacetate
-Third and final NADH and CO2
-OAA is depleted by citrate synthase rxn to make citrate
42.Cholesterol - ANSWER -amphipathic lipid w/ hydrophilic OH and
hydrophobic tail
-B face is methyls that will associate with proteins and the a face associates
with acyl chains
-Moderate fluidity
4
