BIOC 385 D2Q-07 || very Flawless.
Which of the following is the net reaction of the urea cycle?
a. Urea + fumerate + 2 ADP + 2Pi + AMP + PPi --> NH+ + HCO3- + aspartate + 3 ATP
b. NH+ + HCO3- + aspartate + 2 ADP + 2 Pi + AMP + PPi --> urea + fumerate + 3 ATP
c. NH+ + HCO3- + fumerate + 3 ATP --> urea + aspartate + 2 ADP + 2 Pi + AMP + PPi
d. NH+ + HCO3- + aspartate + 3 ATP --> urea + fumerate + 2 ADP + 2 Pi + AMP + PPi correct
answers d. NH+ + HCO3- + aspartate + 3 ATP --> urea + fumerate + 2 ADP + 2 Pi + AMP +
PPi
[Phenylketonuria (1) / Albinism (2)] is characterized by white skin 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.
Choose the best underline word or phrase that correctly completes the sentence and record the
numbers.
a. 1, 4, 5, 7, 10
b. 2, 4, 6, 8, 9
c. 1, 3, 6, 7, 9
d. 2, 3, 5, 7, 10
e. 2, 4, 5, 8, 10 correct answers e. 2, 4, 5, 8, 10
Regulation of protein ubiquitination is most often mediated by modification of
________________.
a. target proteins and E1 ligases
b. the E2-ubiquitin-E3 complex
c. E1 and E2 ligases
d. target proteins and E3 ligases
e. E1 ubiquitin ligase complex correct answers d. target proteins and E3 ligases
Biochemical changes to ______________ regulate protein ubiquitination.
a. target proteins and E1 ligases
b. the E2-ubiquitin-E3 complex
c. target proteins and E3 ligases
d. E1 and E2 ligases correct answers c. target proteins and E3 ligases
, What molecule signals the endothelial cell to produce NO?
a. citrulline
b. phosphate
c. acetylcholine
d. dopamine correct answers c. acetylcholine
Animals cannot synthesize tyrosine from shikimate-3P because they lack EPSP synthase.
However, tyrosine is listed as a non-essential amino in most tables. What is the explanation?
a. tyrosine is essential until reaching puberty, and then after that, it is non-essential because of
hormones
b. tyrosine can be synthesized from phenylalanine, and since phenylalanine is essential, tyrosine
is not
c. most animals do actually contain the enzyme EPSP synthase it is just not expressed all of the
time
d. there are other pathways to synthesize tyrosine from shikimate-3P, so EPSP synthase is not
required
e. tyrosine is not essential because it can be synthesized from tryptophan, and tryptophan is
essential correct answers b. tyrosine can be synthesized from phenylalanine, and since
phenylalanine is essential, tyrosine is not
What is the biochemical explanation for why rapid weight loss is reported with protein-rich
diets?
a. the rapid weight loss is due to ketogenesis and the "melting" of fat away from the thighs and
upper body
b. amino acid degradation results in urea production to remove excess NH4+, so mostly water
weight loss
c. dieters usually over-estimate how much weight they actually lose on a diet and the data are
likely flawed.
d. a protein-rich diet is a high energy regimen that leads to nervous energy and a strong desire to
exercise correct answers b. amino acid degradation results in urea production to remove excess
NH4+, so mostly water weight loss
A person who has phenylketonuria will have an excess amount of ________________ in the cell.
a. phenylalanine
b. pyruvate
c. tyrosine
d. alanine correct answers a. phenylalanine
In the production of urea, the carbon atom comes from __________________.
a. water
b. carbamoyl phosphate
Which of the following is the net reaction of the urea cycle?
a. Urea + fumerate + 2 ADP + 2Pi + AMP + PPi --> NH+ + HCO3- + aspartate + 3 ATP
b. NH+ + HCO3- + aspartate + 2 ADP + 2 Pi + AMP + PPi --> urea + fumerate + 3 ATP
c. NH+ + HCO3- + fumerate + 3 ATP --> urea + aspartate + 2 ADP + 2 Pi + AMP + PPi
d. NH+ + HCO3- + aspartate + 3 ATP --> urea + fumerate + 2 ADP + 2 Pi + AMP + PPi correct
answers d. NH+ + HCO3- + aspartate + 3 ATP --> urea + fumerate + 2 ADP + 2 Pi + AMP +
PPi
[Phenylketonuria (1) / Albinism (2)] is characterized by white skin 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.
Choose the best underline word or phrase that correctly completes the sentence and record the
numbers.
a. 1, 4, 5, 7, 10
b. 2, 4, 6, 8, 9
c. 1, 3, 6, 7, 9
d. 2, 3, 5, 7, 10
e. 2, 4, 5, 8, 10 correct answers e. 2, 4, 5, 8, 10
Regulation of protein ubiquitination is most often mediated by modification of
________________.
a. target proteins and E1 ligases
b. the E2-ubiquitin-E3 complex
c. E1 and E2 ligases
d. target proteins and E3 ligases
e. E1 ubiquitin ligase complex correct answers d. target proteins and E3 ligases
Biochemical changes to ______________ regulate protein ubiquitination.
a. target proteins and E1 ligases
b. the E2-ubiquitin-E3 complex
c. target proteins and E3 ligases
d. E1 and E2 ligases correct answers c. target proteins and E3 ligases
, What molecule signals the endothelial cell to produce NO?
a. citrulline
b. phosphate
c. acetylcholine
d. dopamine correct answers c. acetylcholine
Animals cannot synthesize tyrosine from shikimate-3P because they lack EPSP synthase.
However, tyrosine is listed as a non-essential amino in most tables. What is the explanation?
a. tyrosine is essential until reaching puberty, and then after that, it is non-essential because of
hormones
b. tyrosine can be synthesized from phenylalanine, and since phenylalanine is essential, tyrosine
is not
c. most animals do actually contain the enzyme EPSP synthase it is just not expressed all of the
time
d. there are other pathways to synthesize tyrosine from shikimate-3P, so EPSP synthase is not
required
e. tyrosine is not essential because it can be synthesized from tryptophan, and tryptophan is
essential correct answers b. tyrosine can be synthesized from phenylalanine, and since
phenylalanine is essential, tyrosine is not
What is the biochemical explanation for why rapid weight loss is reported with protein-rich
diets?
a. the rapid weight loss is due to ketogenesis and the "melting" of fat away from the thighs and
upper body
b. amino acid degradation results in urea production to remove excess NH4+, so mostly water
weight loss
c. dieters usually over-estimate how much weight they actually lose on a diet and the data are
likely flawed.
d. a protein-rich diet is a high energy regimen that leads to nervous energy and a strong desire to
exercise correct answers b. amino acid degradation results in urea production to remove excess
NH4+, so mostly water weight loss
A person who has phenylketonuria will have an excess amount of ________________ in the cell.
a. phenylalanine
b. pyruvate
c. tyrosine
d. alanine correct answers a. phenylalanine
In the production of urea, the carbon atom comes from __________________.
a. water
b. carbamoyl phosphate
