UNE BIOCHEMISTRY 1005 FINAL EXAM
(800 QUESTIONS AND ANSWERS)
LATEST UPDATED 20242025 GRADED
A+.
Control of Fatty Acid Synthesis vs. Oxidation - Answer When Insulin is
HIGH --> fatty acid synthesis occurs
When Glucagon is HIGH --> lipolysis, fatty acid B-oxidation, ketogenesis
occur
**These never happen at the same time!
Lipolysis - Answer Process of releasing free fatty acids from
triacylglycerols stored in the adipose IN THE FASTED STATE
Steps of lipolysis - Answer 1) Hormone Sensitive Lipase: activated by
glucagon and epinephrine
TAGs are hydrolyzed into FFAs and glycerol (inhibited by insulin)
2) Long chain FFAs travel bound to albumin to peripheral tissues to be
used as energy source
3) Glycerol travels to liver to be used as gluconeogenesis substrate
4) Acyl-CoA Synthetase: can reconvert FFAs to acyl-CoA to be used for re-
esterification in the adipose (continuous cycle of lipolysis & re-esterification)
Beta Oxidation - Answer Process of generating acetyl-CoA, NADH, and
FADH2 from the oxidation of FFAs taken up by peripheral tissues (mostly
liver & skel. muscle tissue).
Happens in mitochondria. Long chain FFAs cannot cross the mito
membrane, so a transport system is in place.
Ketogenesis - Answer Process of generating ketones from excess acteyl-
CoA produced from Beta-Oxidation
Mitochondrial pathway
,Ketones can be used as fuel by other tissues but cannot be oxidized by... -
Answer The liver.
Skeletal muscle can oxidize ketones.
The brain will oxidize ketones when starving.
Ketogenesis is regulated by... - Answer 1) Activity of lipolysis
2) Cytosolic levels of malonyl-CoA (which inhibit CPTI)
3) Flux through the TCA depending on NADH levels & concentration of
intermediates (especially OAA)
Ketoacidosis can occur from prolonged ketogenesis, such as... - Answer
During starvation and uncontrolled diabetes
Important connections between Beta-Oxidation and other pathways -
Answer 1) It supplies high levels of ATP in the fasted state
2) ATP is required for both process of glucose synthesis via
gluconeogenesis & nitrogen disposal via the urea cycle
3) deficiencies in beta-oxidation can result in hypoglycemia due to inability
to support glucose synthesis (such as CPTI deficiency, or medium chain
acyl-dehydrogenase deficiency)
Fatty Acid Synthesis: Activators & Inhibitors - Answer Activated by insulin
Inhibited by glucagon
Fatty acid synthesis takes place in the... - Answer Cytosol
Fatty acid synthesis: what occurs in the mitochondria? - Answer
Substrates need to be shuttled out of the mitochondria
In the mito:
-Acetyl-CoA and OAA in the mito --> citrate
-Tricarboxylate transporter --> removes excess citrate from the mito
Fatty acid elongation - Answer Requires malonyl-CoA, fatty acyl-CoA and
NADPH.
,This pathway determines the chain length for fatty acids (medium, long,
etc.)
Fatty acid synthesis connection to the PPP - Answer PPP provides
glycerol (for TAG synthesis) and NADPH (for fatty acid synthesis)
Fate of newly synthesized fatty acids - Answer -Fatty acids are NOT stored
in the liver
-instead, they're packaged into VLDL particles as TAGs (along with
cholesterol) and are transported to adipose for storage
HDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Liver
Primary Apo Protein: ApoA
Composition: Cholesterol and Cholesteryl Ester > Triacylglycerol (C and
CE > TG)
Primary Role: reverse cholesterol transport
*HDL is the most dense
LDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Maturation of VLDL
Primary Apo Protein: ApoB100
Composition: Cholesterol and Cholesteryl Ester > Triacylglycerol (C and
CE > TG)
Primary role: cholesterol transport from the liver
VLDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Liver
Primary Apo Protein: ApoB100
Composition: Triacylglycerol > Cholesterol and Cholesteryl Ester (TG > C
and CE)
Primary role: carries newly synthesized TAG from the liver to the adipose
Chylomicron:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Intestine
, Primary Apo Protein: ApoB48
Composition: Triacylglycerol > > Cholesterol > Cholesteryl Ester (TG > > C
> CE)
Primary Role: carries dietary lipids to the adipose for storage
*Chylomicrons are the least dense
ACAT - Answer Acyl-coenzyme A acetyltransferase
Esterifies cholesterol within the cell
LCAT or PCAT - Answer Lecithin cholesterol acyl transferase
Esterifies cholesterol in the plasma when moving in and out of HDL
particles
ABCG1/ABCA1 Transporter - Answer on the cell surface and is
responsible for active transport of cholesterol and lipids out of the cell into
the HDL particle
LDL Receptor - Answer Binds ApoB100 on LDL particles and facilitates the
uptake of LDL particles
SR1 - Answer Scavenger receptor, on liver cells and function in HDL
particle uptake
LPL - Answer Lipoprotein lipase
On vascular epithelium; Cleaves TAGs into glycerol and FFAs to be stored
in the adipose after being reformed into TAGs
ApoE - Answer Apoprotein on chylomicrons and VLDL used for uptake by
the liver
*Transferred to chylomicrons and VLDL from HDL particles
ApoCII - Answer Interacts with LPL (lipoprotein lipase) to activate the
enzyme
*Transferred to chylomicrons and VLDL from HDL particles
(800 QUESTIONS AND ANSWERS)
LATEST UPDATED 20242025 GRADED
A+.
Control of Fatty Acid Synthesis vs. Oxidation - Answer When Insulin is
HIGH --> fatty acid synthesis occurs
When Glucagon is HIGH --> lipolysis, fatty acid B-oxidation, ketogenesis
occur
**These never happen at the same time!
Lipolysis - Answer Process of releasing free fatty acids from
triacylglycerols stored in the adipose IN THE FASTED STATE
Steps of lipolysis - Answer 1) Hormone Sensitive Lipase: activated by
glucagon and epinephrine
TAGs are hydrolyzed into FFAs and glycerol (inhibited by insulin)
2) Long chain FFAs travel bound to albumin to peripheral tissues to be
used as energy source
3) Glycerol travels to liver to be used as gluconeogenesis substrate
4) Acyl-CoA Synthetase: can reconvert FFAs to acyl-CoA to be used for re-
esterification in the adipose (continuous cycle of lipolysis & re-esterification)
Beta Oxidation - Answer Process of generating acetyl-CoA, NADH, and
FADH2 from the oxidation of FFAs taken up by peripheral tissues (mostly
liver & skel. muscle tissue).
Happens in mitochondria. Long chain FFAs cannot cross the mito
membrane, so a transport system is in place.
Ketogenesis - Answer Process of generating ketones from excess acteyl-
CoA produced from Beta-Oxidation
Mitochondrial pathway
,Ketones can be used as fuel by other tissues but cannot be oxidized by... -
Answer The liver.
Skeletal muscle can oxidize ketones.
The brain will oxidize ketones when starving.
Ketogenesis is regulated by... - Answer 1) Activity of lipolysis
2) Cytosolic levels of malonyl-CoA (which inhibit CPTI)
3) Flux through the TCA depending on NADH levels & concentration of
intermediates (especially OAA)
Ketoacidosis can occur from prolonged ketogenesis, such as... - Answer
During starvation and uncontrolled diabetes
Important connections between Beta-Oxidation and other pathways -
Answer 1) It supplies high levels of ATP in the fasted state
2) ATP is required for both process of glucose synthesis via
gluconeogenesis & nitrogen disposal via the urea cycle
3) deficiencies in beta-oxidation can result in hypoglycemia due to inability
to support glucose synthesis (such as CPTI deficiency, or medium chain
acyl-dehydrogenase deficiency)
Fatty Acid Synthesis: Activators & Inhibitors - Answer Activated by insulin
Inhibited by glucagon
Fatty acid synthesis takes place in the... - Answer Cytosol
Fatty acid synthesis: what occurs in the mitochondria? - Answer
Substrates need to be shuttled out of the mitochondria
In the mito:
-Acetyl-CoA and OAA in the mito --> citrate
-Tricarboxylate transporter --> removes excess citrate from the mito
Fatty acid elongation - Answer Requires malonyl-CoA, fatty acyl-CoA and
NADPH.
,This pathway determines the chain length for fatty acids (medium, long,
etc.)
Fatty acid synthesis connection to the PPP - Answer PPP provides
glycerol (for TAG synthesis) and NADPH (for fatty acid synthesis)
Fate of newly synthesized fatty acids - Answer -Fatty acids are NOT stored
in the liver
-instead, they're packaged into VLDL particles as TAGs (along with
cholesterol) and are transported to adipose for storage
HDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Liver
Primary Apo Protein: ApoA
Composition: Cholesterol and Cholesteryl Ester > Triacylglycerol (C and
CE > TG)
Primary Role: reverse cholesterol transport
*HDL is the most dense
LDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Maturation of VLDL
Primary Apo Protein: ApoB100
Composition: Cholesterol and Cholesteryl Ester > Triacylglycerol (C and
CE > TG)
Primary role: cholesterol transport from the liver
VLDL:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Liver
Primary Apo Protein: ApoB100
Composition: Triacylglycerol > Cholesterol and Cholesteryl Ester (TG > C
and CE)
Primary role: carries newly synthesized TAG from the liver to the adipose
Chylomicron:
Origin, Primary Apo Protein, Composition, Primary Role - Answer Origin:
Intestine
, Primary Apo Protein: ApoB48
Composition: Triacylglycerol > > Cholesterol > Cholesteryl Ester (TG > > C
> CE)
Primary Role: carries dietary lipids to the adipose for storage
*Chylomicrons are the least dense
ACAT - Answer Acyl-coenzyme A acetyltransferase
Esterifies cholesterol within the cell
LCAT or PCAT - Answer Lecithin cholesterol acyl transferase
Esterifies cholesterol in the plasma when moving in and out of HDL
particles
ABCG1/ABCA1 Transporter - Answer on the cell surface and is
responsible for active transport of cholesterol and lipids out of the cell into
the HDL particle
LDL Receptor - Answer Binds ApoB100 on LDL particles and facilitates the
uptake of LDL particles
SR1 - Answer Scavenger receptor, on liver cells and function in HDL
particle uptake
LPL - Answer Lipoprotein lipase
On vascular epithelium; Cleaves TAGs into glycerol and FFAs to be stored
in the adipose after being reformed into TAGs
ApoE - Answer Apoprotein on chylomicrons and VLDL used for uptake by
the liver
*Transferred to chylomicrons and VLDL from HDL particles
ApoCII - Answer Interacts with LPL (lipoprotein lipase) to activate the
enzyme
*Transferred to chylomicrons and VLDL from HDL particles
