1
MCAT Test #6
NEWLY FORMATTED DOCUMENT
Which of the following is D. While increased serum glucose is associated with
LEAST likely to the
electrolyte balance for most DKA patients,
contribute to the
there is no evidence presented in the
incidence of cerebral
passage or the literature from which it is
edema?
drawn to suggest that it contributes to the
A. Increased incidence of cerebral edema (choice D is not
cerebral blood causative and thus correct). Cerebral
flow edema would be influenced by processes
B. Increased increasing fluid delivery to or retention of
cerebrospinal fluid
C. Increased
fluid in the brain (choices A, B, and C will
neuronal contribute to cerebral edema and are
intracellular wrong).
fluid
D. Increased serum
glucose
an atom absorbs an
electron and combines it
with one of its protons to
electron capture (type
of decay) make a neutron
so proton # goes down by 1
but neutron # goes up by one
,2
diabetic D. Based on the description in the passage, the
ketoacidosis (DKA) biochemical
process which gives rise to diabetic
occurs as a result of a
ketoacidosis in the context of severe insulin
lack of insulin. This
deficiency is ketogenesis following the
state gives rise to
breakdown of triglycerides in adipose tissue, release
increased release of of free fatty
acids into the blood, and subsequent β-
glucagon from the oxidation of those free fatty acids. Thus the
most direct effect of the administration of
pancreas which spurs insulin would be to reduce the breakdown
of adipose triglycerides (choice D is correct).
the liver to produce While the rate of ketogenesis would decrease
and release glucose upon administration of insulin to a DKA
patient, all of the steps of ketogenesis in
via glycogenolysis Figure 1 would be affected
and gluconeogenesis. downstream from the decrease in
Lipolysis also triglyceride breakdown (decreased rate of
increases in adipose the ketogenic steps described in answer
tissue, releasing free choices A, B, and C would be indirect
fatty acids (FFAs) into effects of insulin administration; thus, these
the bloodstream. answer choices are incorrect).
These FFAs are
broken down by the
liver into acetyl-CoA
which is, in turn,
converted to
acetoacetate
and β-hydroxybutyrate,
the
latter of which can be
utilized by most tissues
in the body as an
energy source. The
conversion
of acetyl-CoA to β-
hydroxybutyric acid is
,3
shown in Figure 1
The administration of
insulin to a patient with
diabetic
ketoacidosis will have
the most direct effect
on which of the
following reactions?
Combination of two
A.
acetyl-
CoA
molecules
into
acetoacetyl-
CoA
B. Conversion of
acetoacetyl- CoA to
HMG-CoA
C. Breakdown of
acetoacetate
into acetone and D-β-
hydroxyb
Which of the following C. Item I is false: Due to the lack of insulin,
metabolic cells will experience a shortage of
derangements are intracellular glucose due to a lack of
most likely to be expression of GLUT4 channels which are
found in Diabetic responsible for transporting
ketoacidosis? extracellular glucose in to the intracellular
compartment (choices A and D are wrong).
Accumulation of Item II is true: the passage states that a lack of
intracellular glucose insulin leads to increase lipolysis and
, 4
Increased plasma release of free fatty acids into the
fatty acid bloodstream (choice B can be eliminated
concentration and choice C is correct). Note that Item III is
Decrease in plasma pH also true: the "acidosis" part of
"ketoacidosis" implies a decreased plasma
A. I only
pH.
B. III only
C. II and III only
D. I, II, and III
MCAT Test #6
NEWLY FORMATTED DOCUMENT
Which of the following is D. While increased serum glucose is associated with
LEAST likely to the
electrolyte balance for most DKA patients,
contribute to the
there is no evidence presented in the
incidence of cerebral
passage or the literature from which it is
edema?
drawn to suggest that it contributes to the
A. Increased incidence of cerebral edema (choice D is not
cerebral blood causative and thus correct). Cerebral
flow edema would be influenced by processes
B. Increased increasing fluid delivery to or retention of
cerebrospinal fluid
C. Increased
fluid in the brain (choices A, B, and C will
neuronal contribute to cerebral edema and are
intracellular wrong).
fluid
D. Increased serum
glucose
an atom absorbs an
electron and combines it
with one of its protons to
electron capture (type
of decay) make a neutron
so proton # goes down by 1
but neutron # goes up by one
,2
diabetic D. Based on the description in the passage, the
ketoacidosis (DKA) biochemical
process which gives rise to diabetic
occurs as a result of a
ketoacidosis in the context of severe insulin
lack of insulin. This
deficiency is ketogenesis following the
state gives rise to
breakdown of triglycerides in adipose tissue, release
increased release of of free fatty
acids into the blood, and subsequent β-
glucagon from the oxidation of those free fatty acids. Thus the
most direct effect of the administration of
pancreas which spurs insulin would be to reduce the breakdown
of adipose triglycerides (choice D is correct).
the liver to produce While the rate of ketogenesis would decrease
and release glucose upon administration of insulin to a DKA
patient, all of the steps of ketogenesis in
via glycogenolysis Figure 1 would be affected
and gluconeogenesis. downstream from the decrease in
Lipolysis also triglyceride breakdown (decreased rate of
increases in adipose the ketogenic steps described in answer
tissue, releasing free choices A, B, and C would be indirect
fatty acids (FFAs) into effects of insulin administration; thus, these
the bloodstream. answer choices are incorrect).
These FFAs are
broken down by the
liver into acetyl-CoA
which is, in turn,
converted to
acetoacetate
and β-hydroxybutyrate,
the
latter of which can be
utilized by most tissues
in the body as an
energy source. The
conversion
of acetyl-CoA to β-
hydroxybutyric acid is
,3
shown in Figure 1
The administration of
insulin to a patient with
diabetic
ketoacidosis will have
the most direct effect
on which of the
following reactions?
Combination of two
A.
acetyl-
CoA
molecules
into
acetoacetyl-
CoA
B. Conversion of
acetoacetyl- CoA to
HMG-CoA
C. Breakdown of
acetoacetate
into acetone and D-β-
hydroxyb
Which of the following C. Item I is false: Due to the lack of insulin,
metabolic cells will experience a shortage of
derangements are intracellular glucose due to a lack of
most likely to be expression of GLUT4 channels which are
found in Diabetic responsible for transporting
ketoacidosis? extracellular glucose in to the intracellular
compartment (choices A and D are wrong).
Accumulation of Item II is true: the passage states that a lack of
intracellular glucose insulin leads to increase lipolysis and
, 4
Increased plasma release of free fatty acids into the
fatty acid bloodstream (choice B can be eliminated
concentration and choice C is correct). Note that Item III is
Decrease in plasma pH also true: the "acidosis" part of
"ketoacidosis" implies a decreased plasma
A. I only
pH.
B. III only
C. II and III only
D. I, II, and III
