BIOCHEM 384
BIOC 384 EXAM 3 QUESTIONS AND
ANSWERS 2025
irreversible inhibitor - Lecture 7: Acetylcholinesterase is an importance enzyme in the
nervous system. Acetylcholinesterase activity is blocked by the nerve agent sarin gas,
which forms a covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n)
Uncompetitive - Lecture 7: An inhibitor that binds only to the ES complex and not free
enzyme is known as a(n) _______ inhibitor.
Tyr --> Phe - Lecture 7: An enzyme undergoes a mutation that causes it to lose the ability
to be regulated via phosphorylation. Which of the following mutations may lead to this
loss of regulation? Assume that the overall structure is not altered by the mutation.
B. Glutamine binding to the uridylytransferase
C. Deuridylation of the glutamine synthetase adenylyltransferase
A. Adenylation of the glutamine synthetase - Lecture 7: Put the following steps in the
correct order describing inhibition of glutamine synthetase by a metabolite allosteric
effector
D. first messenger
C. receptor protein
A. upstream signaling protein
B. second messenger
F. downstream signaling protein
E. target proteins - Lecture 7: Put the following signal transduction pathway steps in the
correct order.
BIOCHEM 384
,BIOCHEM 384
Stimulator of cGMP phosphodiesterase - Lecture 7: Muscle relaxation in response to
neuronal stimulation and nitric oxide signaling would be reduced if a(n) ______ was
present.
Activate adenylate cyclase - Lecture 7: The Gs-alpha subunit of trimeric G proteins can
function to
the intrinsic pseudosubstrate peptide is bound to the active site - Lecture 7: When protein
kinase A (PKA) is inactive, which of the following is true?
C. ligand binding, receptor dimerization, and kinase activation
A.phosphorylation of RTK cytoplasmic tails
D. protein binding to RTK phosphotyrosines and phosphorylation of target proteins
B. activation of downstream signaling pathways - Lecture 8: Place the following steps
describing receptor tyrosine kinase (RTK) signaling in proper order
Glucose uptake rates increase and lower blood glucose levels - Lecture 8: Which of the
following processes occurs after activation of the PI-3K pathways by insulin signaling?
PIP3 - Lecture 8: A new protein is discovered that contains a pleckstrin homology
domain. Which of the following is likely to bind to the protein?
FADD - Lecture 8: Which protein is part of the TNF receptor-activated programmed cell
death signaling pathway?
It is activated by auto-cleavage - Lecture 8: Which of the following statements is true of
procaspase 8?
BIOCHEM 384
, BIOCHEM 384
Only one of the cell types expresses the cognate steroid receptor - Lecture 8: Cultures of
two different human cell types are exposed to the same steroid signaling molecule.
Analysis of gene expression shows that only one of the cell types activated gene
expression characteristic of the steroid signaling pathway. Which of the following is the
most likely explanation for this difference?
arthritis, asthma, and dermatitis - Lecture 8: Which human disease states are treated by
glucocorticoids based on the anti-inflammatory response of cells to glucocorticoid
treatment?
Metabolites - Lecture 8: Flux is defined as the rate at which ______ is/are interconverted.
Biochemical reactions that convert chemical energy into work - Lecture 8: Metabolism is
best defined as a collection of
strongly favored in the forward direction - Lecture 8: In the reaction A --> B, what can be
said about the directionality of the reaction if when starting with equal concentrations of
A and B at time zero (To), you find that at equilibrium 30 minutes (t30) later, that [B] >>
[A]?
Link it to a favorable reaction - Lecture 8: How can an unfavorable reaction (deltaG' > 0)
still occur in a metabolic pathway?
Fructose is a 5-membered ring and glucose is a 6-membered ring - Lecture 9: Glucose
and fructose are both C6H12O6. What is the structural difference between them?
Lactose; Gal(beta 1 -->4)Glc - Lecture 9: Name the following disaccharide using the
common name and the descriptive nomenclature.
BIOCHEM 384
BIOC 384 EXAM 3 QUESTIONS AND
ANSWERS 2025
irreversible inhibitor - Lecture 7: Acetylcholinesterase is an importance enzyme in the
nervous system. Acetylcholinesterase activity is blocked by the nerve agent sarin gas,
which forms a covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n)
Uncompetitive - Lecture 7: An inhibitor that binds only to the ES complex and not free
enzyme is known as a(n) _______ inhibitor.
Tyr --> Phe - Lecture 7: An enzyme undergoes a mutation that causes it to lose the ability
to be regulated via phosphorylation. Which of the following mutations may lead to this
loss of regulation? Assume that the overall structure is not altered by the mutation.
B. Glutamine binding to the uridylytransferase
C. Deuridylation of the glutamine synthetase adenylyltransferase
A. Adenylation of the glutamine synthetase - Lecture 7: Put the following steps in the
correct order describing inhibition of glutamine synthetase by a metabolite allosteric
effector
D. first messenger
C. receptor protein
A. upstream signaling protein
B. second messenger
F. downstream signaling protein
E. target proteins - Lecture 7: Put the following signal transduction pathway steps in the
correct order.
BIOCHEM 384
,BIOCHEM 384
Stimulator of cGMP phosphodiesterase - Lecture 7: Muscle relaxation in response to
neuronal stimulation and nitric oxide signaling would be reduced if a(n) ______ was
present.
Activate adenylate cyclase - Lecture 7: The Gs-alpha subunit of trimeric G proteins can
function to
the intrinsic pseudosubstrate peptide is bound to the active site - Lecture 7: When protein
kinase A (PKA) is inactive, which of the following is true?
C. ligand binding, receptor dimerization, and kinase activation
A.phosphorylation of RTK cytoplasmic tails
D. protein binding to RTK phosphotyrosines and phosphorylation of target proteins
B. activation of downstream signaling pathways - Lecture 8: Place the following steps
describing receptor tyrosine kinase (RTK) signaling in proper order
Glucose uptake rates increase and lower blood glucose levels - Lecture 8: Which of the
following processes occurs after activation of the PI-3K pathways by insulin signaling?
PIP3 - Lecture 8: A new protein is discovered that contains a pleckstrin homology
domain. Which of the following is likely to bind to the protein?
FADD - Lecture 8: Which protein is part of the TNF receptor-activated programmed cell
death signaling pathway?
It is activated by auto-cleavage - Lecture 8: Which of the following statements is true of
procaspase 8?
BIOCHEM 384
, BIOCHEM 384
Only one of the cell types expresses the cognate steroid receptor - Lecture 8: Cultures of
two different human cell types are exposed to the same steroid signaling molecule.
Analysis of gene expression shows that only one of the cell types activated gene
expression characteristic of the steroid signaling pathway. Which of the following is the
most likely explanation for this difference?
arthritis, asthma, and dermatitis - Lecture 8: Which human disease states are treated by
glucocorticoids based on the anti-inflammatory response of cells to glucocorticoid
treatment?
Metabolites - Lecture 8: Flux is defined as the rate at which ______ is/are interconverted.
Biochemical reactions that convert chemical energy into work - Lecture 8: Metabolism is
best defined as a collection of
strongly favored in the forward direction - Lecture 8: In the reaction A --> B, what can be
said about the directionality of the reaction if when starting with equal concentrations of
A and B at time zero (To), you find that at equilibrium 30 minutes (t30) later, that [B] >>
[A]?
Link it to a favorable reaction - Lecture 8: How can an unfavorable reaction (deltaG' > 0)
still occur in a metabolic pathway?
Fructose is a 5-membered ring and glucose is a 6-membered ring - Lecture 9: Glucose
and fructose are both C6H12O6. What is the structural difference between them?
Lactose; Gal(beta 1 -->4)Glc - Lecture 9: Name the following disaccharide using the
common name and the descriptive nomenclature.
BIOCHEM 384
