1
BIOC 385 EXAC 3 LATEST UPDATES -2025/2026- ACTUAL
QUESTIONS WITH VERIFIED ANSWERS ALREADY GRADED A+
GUARANTEED SUCCESS
After food enters the stomach, gastrin triggers the release of __________ and
secretion of __________.
gastric juices; pepsinogen
What is the biochemical explanation for why rapid weight loss is reported with
protein-rich diets?
Amino acid degradation results in urea production to remove excess NH4+, so
mostly water weight loss.
Which of the following amino acids are required in the first step of heme
biosynthesis?
Glycine
What is the regulatory mechanism by which arginine stimulates flux through the
urea cycle?
Arginine stimulates the production of the allosteric activator N-acetylglutamate
A person who has alkaptonuria is easily diagnosed from their black urine. What
causes the black color?
Oxidation of homogentisate
Aspartate is a(n) ________ amino acid, so if a person had a diet that contained no
aspartate then ________.
Nonessential; aspartate could be synthesized from other intermediates
What is the mechanism by which glyphosate, the active ingredient in Roundup,
kills plants?
, 2
Glyphosate is a competitive inhibitor of plant EPSP synthase.
Phenylketonuria (1) / Albinism (2) is characterized by white skin due to a defect in
the enzyme tyrosinase, which leads to a block in the pathway needed to
synthesize adrenaline (3) / melanin (4). Animals with this condition have an
increased risk of skin cancer (5) / mental illness (6). The genetic disease albinism
(7) / phenylketonuria (8) is caused by a defect in the enzyme phenylalanine
hydroxylase, which leads to the accumulation of tyrosine (9) / phenylalanine (10)
derivatives that are toxic metabolites
2, 4, 5, 8, 10
What molecule signals the endothelial cell to produce NO?
acetylcholine
Angina patients sometimes carry nitroglycerine pills with them___________
as a rapid source of NO for blood vessel dilation
Biochemical changes to _______________ regulate protein ubiquitination.
target proteins and E3 ligases
Compare the function of pepsin with that of secretin.
Pepsin cleaves polypeptides, whereas secretin neutralizes pH back to 7.
The shikimate pathway involves the ________________.
condensation of phosphoenolpyruvate and erythrose-4-phosphate.
It is important that proteolytic enzymes in the lysosome are optimized to work at
low pH because low pH_____________.
enhances protein denaturing.
What nitrogen source is used to produce carbamoyl phosphate?
ammonia
Regulation of protein ubiquitination is most often mediated by modification of
___________.
Target proteins and E3 ligases.
, 3
Nitrogen obtained from dietary proteins is incorporated into the urea cycle
_______.
Through conversion to aspartate
Alanine, cysteine, glycine, and serine are all considered _____ amino acids.
Glucogenic
A negative nitrogen balance in a person would be an indicator of ________.
Starvation.
Arginine, leucine, and lysine are all essential amino acids. This means that they
are____________.
Only available from dietary sources
Why does it make sense that tadpoles (which live in water) have low levels of the
enzyme arginase, but after metamorphosis into frogs (which live on land), their
arginase levels increase?
Tadpoles living in water can excrete ammonia directly, but once on land, they
need to excrete urea.
We have an expert-written solution to this problem!
Which of the following is the reaction for nitric oxide synthase?
L-arginine + 1.5 NADPH + H+ + 2O2 → citrulline + NO + 1.5 NADP+
Nitrogen in biological compounds ultimately comes from ___________.
Nitrogen gas
In the production of urea, the carbon atom comes from______________.
The citrate cycle
Why is ingesting large amounts of L-arginine a viable treatment for
argininosuccinase deficiency?
Arginine is converted to ornithine, which provides urea cycle intermediates Which
of the following chemical moieties compost tetrahydrofolate needed for nitrogen
removal.
BIOC 385 EXAC 3 LATEST UPDATES -2025/2026- ACTUAL
QUESTIONS WITH VERIFIED ANSWERS ALREADY GRADED A+
GUARANTEED SUCCESS
After food enters the stomach, gastrin triggers the release of __________ and
secretion of __________.
gastric juices; pepsinogen
What is the biochemical explanation for why rapid weight loss is reported with
protein-rich diets?
Amino acid degradation results in urea production to remove excess NH4+, so
mostly water weight loss.
Which of the following amino acids are required in the first step of heme
biosynthesis?
Glycine
What is the regulatory mechanism by which arginine stimulates flux through the
urea cycle?
Arginine stimulates the production of the allosteric activator N-acetylglutamate
A person who has alkaptonuria is easily diagnosed from their black urine. What
causes the black color?
Oxidation of homogentisate
Aspartate is a(n) ________ amino acid, so if a person had a diet that contained no
aspartate then ________.
Nonessential; aspartate could be synthesized from other intermediates
What is the mechanism by which glyphosate, the active ingredient in Roundup,
kills plants?
, 2
Glyphosate is a competitive inhibitor of plant EPSP synthase.
Phenylketonuria (1) / Albinism (2) is characterized by white skin due to a defect in
the enzyme tyrosinase, which leads to a block in the pathway needed to
synthesize adrenaline (3) / melanin (4). Animals with this condition have an
increased risk of skin cancer (5) / mental illness (6). The genetic disease albinism
(7) / phenylketonuria (8) is caused by a defect in the enzyme phenylalanine
hydroxylase, which leads to the accumulation of tyrosine (9) / phenylalanine (10)
derivatives that are toxic metabolites
2, 4, 5, 8, 10
What molecule signals the endothelial cell to produce NO?
acetylcholine
Angina patients sometimes carry nitroglycerine pills with them___________
as a rapid source of NO for blood vessel dilation
Biochemical changes to _______________ regulate protein ubiquitination.
target proteins and E3 ligases
Compare the function of pepsin with that of secretin.
Pepsin cleaves polypeptides, whereas secretin neutralizes pH back to 7.
The shikimate pathway involves the ________________.
condensation of phosphoenolpyruvate and erythrose-4-phosphate.
It is important that proteolytic enzymes in the lysosome are optimized to work at
low pH because low pH_____________.
enhances protein denaturing.
What nitrogen source is used to produce carbamoyl phosphate?
ammonia
Regulation of protein ubiquitination is most often mediated by modification of
___________.
Target proteins and E3 ligases.
, 3
Nitrogen obtained from dietary proteins is incorporated into the urea cycle
_______.
Through conversion to aspartate
Alanine, cysteine, glycine, and serine are all considered _____ amino acids.
Glucogenic
A negative nitrogen balance in a person would be an indicator of ________.
Starvation.
Arginine, leucine, and lysine are all essential amino acids. This means that they
are____________.
Only available from dietary sources
Why does it make sense that tadpoles (which live in water) have low levels of the
enzyme arginase, but after metamorphosis into frogs (which live on land), their
arginase levels increase?
Tadpoles living in water can excrete ammonia directly, but once on land, they
need to excrete urea.
We have an expert-written solution to this problem!
Which of the following is the reaction for nitric oxide synthase?
L-arginine + 1.5 NADPH + H+ + 2O2 → citrulline + NO + 1.5 NADP+
Nitrogen in biological compounds ultimately comes from ___________.
Nitrogen gas
In the production of urea, the carbon atom comes from______________.
The citrate cycle
Why is ingesting large amounts of L-arginine a viable treatment for
argininosuccinase deficiency?
Arginine is converted to ornithine, which provides urea cycle intermediates Which
of the following chemical moieties compost tetrahydrofolate needed for nitrogen
removal.
