NBCE BOARDS PART 1 –
BIOCHEMISTRY PRACTICE EXAM
2023-2024
_______ is the precursor to all steroids & is the most abundant _______ in humans,
derived from Acetyl-CoA - Answer-Cholesterol
Sterol
Rate limiting enzyme of cholesterol synthesis - Answer-HMG-CoA reductase
HMG-CoA reductase is inhibited by _________ therefore slowing production of
cholesterol. - Answer-Cholesterol
Rate limiting enzyme of Steroid biosynthesis - Answer-Desmolase
Cholesterol is converted to _________ via desmolase, then further to ________ and
then all other steroids. - Answer-Pregnenolone
Progesterone
Cholesterol is eliminated in _________ because fiber binds to _______ to increase
cholesterol elimination. - Answer-Feces
Bile salts
HMG-CoA Synthase is the rate limiting enzyme of ______________. - Answer-Ketone
body synthesis
Lipoproteins transport ____________ in the blood. - Answer-Lipids
Lipoproteins are comprised of _____________ and surround hydrophobic core
containing _______________. - Answer-Monolayer shell of polar lipids & proteins
Cholesterol esters &/or triglycerides
Chylomicrons are produced & secreted by ____________ and are produced in
response to ___________. They carry triacylglycerols to _________. - Answer-Intestinal
mucosal cells
Dietary intake of fats
Peripheral tissues
Chylomicrons carry both ________ & _________. - Answer-Dietary fats
Cholesterol
Largest Lipoprotein - Answer-VLDL
,VLDL is synthesized & secreted from the _________, and transports triacylglycerols to
__________. - Answer-Liver
Peripheral tissues
VLDL transports ____________. - Answer-Endogenous TAGs
LDL is derived from ________ and its function is to transport cholesterol from the
________ to the ___________. It contains the greatest amount of ________. - Answer-
VLDL
Liver
Peripheral tissues
Cholesterol
HDL is synthesized & secreted from the ________ and its function is to transport
cholesterol from the __________ to the _______. It is the _______ lipoprotein. -
Answer-Liver
Peripheral tissues
Liver
Smallest
Increased plasma levels of LDL create an increased risk for _______. - Answer-Heart
disease
Increased HDL indicates decreased risk of ________. - Answer-Heart disease
Lipoprotein Lipase - Answer-required for uptake of triglycerides/FAs carried by VLDL &
chylomicrons
DNA & RNA are composed of ____________, a ____________, and a
________________. - Answer-Phosphate
Pentose sugar (ribose & deoxyribose)
Nitrogenous base
Purines - Answer-Adenine
Guanine
"Pure As Gold"
Purine nitrogen is derived from which amino acids? - Answer-Aspartate
Glycine
Glutamine
Intermediates in purine metabolism (2) - Answer-Hypoxanthine
Xanthine
, Xanthine leads to __________, and ____________ is the rate limiting enzyme of purine
breakdown. - Answer-Uric acid
xanthine oxidase
Pyrimidines - Answer-Thymine (DNA)
Uracil (RNA)
Cytosine
"king TUC lives in a pyramid"
Nucleosides = _______ + ___________ - Answer-Pentose sugar
Nitrogenous base
Nucleotides = ___________ + ____________ + ___________ - Answer-Pentose sugar
Nitrogenous base
Phosphate
Base pairs of DNA - Answer-A-T
G-C
Uracil replaces _______ in RNA - Answer-Thymine
A-U
Single stranded RNA has no __________ - Answer-Base pairs
Phosphodiester bonds in DNA & RNA are between the _______ & _______ of another
sugar. These are ________bonds. - Answer-3' C
5' C
Covalent
H+ bonds are present only in _________. - Answer-DNA
Replication occurs at the __________ during the ______ phase of the cell cycle. -
Answer-Nucleus
S-phase
Replication occurs in the __________ direction - Answer-5' to 3'
Replication is anti-____________ & non-____________. - Answer-Parallel
Comparable
Enzyme of replication - Answer-DNA polymerase
Transcription is the process of DNA transcribing to ________ and occurs at the
__________ in the 5' to 3' direction. - Answer-mRNA
Nucleus
BIOCHEMISTRY PRACTICE EXAM
2023-2024
_______ is the precursor to all steroids & is the most abundant _______ in humans,
derived from Acetyl-CoA - Answer-Cholesterol
Sterol
Rate limiting enzyme of cholesterol synthesis - Answer-HMG-CoA reductase
HMG-CoA reductase is inhibited by _________ therefore slowing production of
cholesterol. - Answer-Cholesterol
Rate limiting enzyme of Steroid biosynthesis - Answer-Desmolase
Cholesterol is converted to _________ via desmolase, then further to ________ and
then all other steroids. - Answer-Pregnenolone
Progesterone
Cholesterol is eliminated in _________ because fiber binds to _______ to increase
cholesterol elimination. - Answer-Feces
Bile salts
HMG-CoA Synthase is the rate limiting enzyme of ______________. - Answer-Ketone
body synthesis
Lipoproteins transport ____________ in the blood. - Answer-Lipids
Lipoproteins are comprised of _____________ and surround hydrophobic core
containing _______________. - Answer-Monolayer shell of polar lipids & proteins
Cholesterol esters &/or triglycerides
Chylomicrons are produced & secreted by ____________ and are produced in
response to ___________. They carry triacylglycerols to _________. - Answer-Intestinal
mucosal cells
Dietary intake of fats
Peripheral tissues
Chylomicrons carry both ________ & _________. - Answer-Dietary fats
Cholesterol
Largest Lipoprotein - Answer-VLDL
,VLDL is synthesized & secreted from the _________, and transports triacylglycerols to
__________. - Answer-Liver
Peripheral tissues
VLDL transports ____________. - Answer-Endogenous TAGs
LDL is derived from ________ and its function is to transport cholesterol from the
________ to the ___________. It contains the greatest amount of ________. - Answer-
VLDL
Liver
Peripheral tissues
Cholesterol
HDL is synthesized & secreted from the ________ and its function is to transport
cholesterol from the __________ to the _______. It is the _______ lipoprotein. -
Answer-Liver
Peripheral tissues
Liver
Smallest
Increased plasma levels of LDL create an increased risk for _______. - Answer-Heart
disease
Increased HDL indicates decreased risk of ________. - Answer-Heart disease
Lipoprotein Lipase - Answer-required for uptake of triglycerides/FAs carried by VLDL &
chylomicrons
DNA & RNA are composed of ____________, a ____________, and a
________________. - Answer-Phosphate
Pentose sugar (ribose & deoxyribose)
Nitrogenous base
Purines - Answer-Adenine
Guanine
"Pure As Gold"
Purine nitrogen is derived from which amino acids? - Answer-Aspartate
Glycine
Glutamine
Intermediates in purine metabolism (2) - Answer-Hypoxanthine
Xanthine
, Xanthine leads to __________, and ____________ is the rate limiting enzyme of purine
breakdown. - Answer-Uric acid
xanthine oxidase
Pyrimidines - Answer-Thymine (DNA)
Uracil (RNA)
Cytosine
"king TUC lives in a pyramid"
Nucleosides = _______ + ___________ - Answer-Pentose sugar
Nitrogenous base
Nucleotides = ___________ + ____________ + ___________ - Answer-Pentose sugar
Nitrogenous base
Phosphate
Base pairs of DNA - Answer-A-T
G-C
Uracil replaces _______ in RNA - Answer-Thymine
A-U
Single stranded RNA has no __________ - Answer-Base pairs
Phosphodiester bonds in DNA & RNA are between the _______ & _______ of another
sugar. These are ________bonds. - Answer-3' C
5' C
Covalent
H+ bonds are present only in _________. - Answer-DNA
Replication occurs at the __________ during the ______ phase of the cell cycle. -
Answer-Nucleus
S-phase
Replication occurs in the __________ direction - Answer-5' to 3'
Replication is anti-____________ & non-____________. - Answer-Parallel
Comparable
Enzyme of replication - Answer-DNA polymerase
Transcription is the process of DNA transcribing to ________ and occurs at the
__________ in the 5' to 3' direction. - Answer-mRNA
Nucleus
