B/B Uworld MCAT GRADE A+ Q&A
Increase Ventricular filling -> Increased Stroke volume -> Increase cardiac input ->
_____ Vascular Resistance - (correct answer)Decreased
*Same for reversed
Reduced ventricular filling would lead to LESS blood being expelled from the ventricle
with each contraction and ______ CO. - (correct answer)Decreased
Compared with healthy individual's ECG, the patient's ECG shows _____ waves of AV
depolarization over the same time period.
*increased # of APs fired from patient's SA and AV nodal cells, lead to ___ frequent
atrial and ventricular contraction
*depolarization and AP generation depend on Na+, Ca+ influx into cells -- more rapid
influx of (+++) ions into SA nodal cells lead to ___ APs firing from SA node and ___
frequent atrial contraction - (correct answer)more,
more,
increased, more
CO2+H2O⇋H2CO3⇋HCO−3+H+
The patient is noted to have decreased pulmonary gas exchange. Given this, which of
the following is most likely to occur in the patient's blood if this condition is left
untreated? - (correct answer)More H2CO3 will be produced and blood pH will decrease.
Excess fluid in the patient's lungs is most likely caused by which of the following at the
pulmonary sites of gas exchange?
,A.Increased protein concentration in the blood flowing through pulmonary capillaries
B.Decreased osmotic pressure in the interstitial fluid surrounding the pulmonary
capillaries
C.Increased hydrostatic pressure within pulmonary capillaries
D.Decreased volume of blood flowing through the pulmonary capillaries - (correct
answer)C. Increased hydrostatic pressure within pulmonary capillaries
*Pulmonary edema
* increase in hydrostatic pressure exerted on capillary walls -> High hydrostatic
pressure would increase the rate of fluid leakage into the interstitial space surrounding
pulmonary capillaries, causing excess fluid accumulation in the lungs.
The genetic code is said to be degenerate because there are 64 different codons, but
translation produces only 20 unique amino acids. The degeneracy of the genetic code is
due to which mechanism?
A.Exclusion of protein coding regions from mature mRNA
B.Errors during tRNA charging
C.Ambiguity of the tRNA for the amino acid
D.Nontraditional base pairing of the anticodon with the third base of the codon - (correct
answer)D.Nontraditional base pairing of the anticodon with the third base of the codon
,*This hypothesis states that the first two nucleotides on the mRNA codon require
traditional (Watson-Crick) base pairing with their complementary nucleotides on the
tRNA anticodon, but third nucleotide on the codon may undergo less stringent
("wobble") base pairing in a non-Watson-Crick manner.
*Codon degeneracy is explained by nontraditional base pairing at the third position of
the codon and anticodon.
Juxtamedullary nephrons have ___ loops of Henle extending deep into the salty
medulla to ____ water reabsorption
*Cortical nephrons have ___ loops of Henle extending shorter distances into the
medulla, making them ___ efficient at water reabsorption. - (correct answer)-long,
maximize
-shorter, less
*Camels absorb more water in water-deficient environments -> camels have higher # of
juxtamedullary nephrons & lower # of cortical nephrons
juxtamedullary nephrons - (correct answer)nephrons with well-developed loops of Henle
that extend deeply into the renal medulla
cortical nephrons - (correct answer)85% of all nephrons
short nephron loops
efferent arterioles branch into peritubular capillaries around PCT and DCT
What is the size of the pSKII plasmid after it is digested by EcoRI and XhoI and the
cldnk gene is inserted?
*Given:
, pSKII= 2958 bp; ECORI -> Xhol= 32 bp; cldnk= 915bp - (correct answer)2958 (pSKII)
plasmid− 32 (Xhol) digested + 915 (cldnK) inserted = 3841 bp
If cldnk mRNA is found in the same cells as the mRNA, then cldnk must be expressed in
oligodendrocytes.
*if probe that is complementary to cldnk mRNA hybridizes to cells that also express
plp1A, then cldnk is expressed in oligodendrocytes. - (correct answer)...
A scientist proposed that ectopic endometrial cells contain extra copies of the VEGF
gene. Given this information, which of the following techniques can be used to analyze
VEGF gene count?
I. DNA sequencing
II. Northern blot
III. Southern blot
"... An enzyme-linked immunosorbent assay (ELISA) was used to characterize the
concentration of VEGF protein present within these samples..." - (correct answer)I, III.
DNA sequencing, Southern blot
-Southern blot: detect a particular sequence of DNA
-DNA sequencing and Southern blotting are ____ assays are used to assess relative
quantity of genes between tissue types.
-Northern blotting is an _____ assay used to assess gene expression in different
tissues. - (correct answer)DNA,
RNA
Increase Ventricular filling -> Increased Stroke volume -> Increase cardiac input ->
_____ Vascular Resistance - (correct answer)Decreased
*Same for reversed
Reduced ventricular filling would lead to LESS blood being expelled from the ventricle
with each contraction and ______ CO. - (correct answer)Decreased
Compared with healthy individual's ECG, the patient's ECG shows _____ waves of AV
depolarization over the same time period.
*increased # of APs fired from patient's SA and AV nodal cells, lead to ___ frequent
atrial and ventricular contraction
*depolarization and AP generation depend on Na+, Ca+ influx into cells -- more rapid
influx of (+++) ions into SA nodal cells lead to ___ APs firing from SA node and ___
frequent atrial contraction - (correct answer)more,
more,
increased, more
CO2+H2O⇋H2CO3⇋HCO−3+H+
The patient is noted to have decreased pulmonary gas exchange. Given this, which of
the following is most likely to occur in the patient's blood if this condition is left
untreated? - (correct answer)More H2CO3 will be produced and blood pH will decrease.
Excess fluid in the patient's lungs is most likely caused by which of the following at the
pulmonary sites of gas exchange?
,A.Increased protein concentration in the blood flowing through pulmonary capillaries
B.Decreased osmotic pressure in the interstitial fluid surrounding the pulmonary
capillaries
C.Increased hydrostatic pressure within pulmonary capillaries
D.Decreased volume of blood flowing through the pulmonary capillaries - (correct
answer)C. Increased hydrostatic pressure within pulmonary capillaries
*Pulmonary edema
* increase in hydrostatic pressure exerted on capillary walls -> High hydrostatic
pressure would increase the rate of fluid leakage into the interstitial space surrounding
pulmonary capillaries, causing excess fluid accumulation in the lungs.
The genetic code is said to be degenerate because there are 64 different codons, but
translation produces only 20 unique amino acids. The degeneracy of the genetic code is
due to which mechanism?
A.Exclusion of protein coding regions from mature mRNA
B.Errors during tRNA charging
C.Ambiguity of the tRNA for the amino acid
D.Nontraditional base pairing of the anticodon with the third base of the codon - (correct
answer)D.Nontraditional base pairing of the anticodon with the third base of the codon
,*This hypothesis states that the first two nucleotides on the mRNA codon require
traditional (Watson-Crick) base pairing with their complementary nucleotides on the
tRNA anticodon, but third nucleotide on the codon may undergo less stringent
("wobble") base pairing in a non-Watson-Crick manner.
*Codon degeneracy is explained by nontraditional base pairing at the third position of
the codon and anticodon.
Juxtamedullary nephrons have ___ loops of Henle extending deep into the salty
medulla to ____ water reabsorption
*Cortical nephrons have ___ loops of Henle extending shorter distances into the
medulla, making them ___ efficient at water reabsorption. - (correct answer)-long,
maximize
-shorter, less
*Camels absorb more water in water-deficient environments -> camels have higher # of
juxtamedullary nephrons & lower # of cortical nephrons
juxtamedullary nephrons - (correct answer)nephrons with well-developed loops of Henle
that extend deeply into the renal medulla
cortical nephrons - (correct answer)85% of all nephrons
short nephron loops
efferent arterioles branch into peritubular capillaries around PCT and DCT
What is the size of the pSKII plasmid after it is digested by EcoRI and XhoI and the
cldnk gene is inserted?
*Given:
, pSKII= 2958 bp; ECORI -> Xhol= 32 bp; cldnk= 915bp - (correct answer)2958 (pSKII)
plasmid− 32 (Xhol) digested + 915 (cldnK) inserted = 3841 bp
If cldnk mRNA is found in the same cells as the mRNA, then cldnk must be expressed in
oligodendrocytes.
*if probe that is complementary to cldnk mRNA hybridizes to cells that also express
plp1A, then cldnk is expressed in oligodendrocytes. - (correct answer)...
A scientist proposed that ectopic endometrial cells contain extra copies of the VEGF
gene. Given this information, which of the following techniques can be used to analyze
VEGF gene count?
I. DNA sequencing
II. Northern blot
III. Southern blot
"... An enzyme-linked immunosorbent assay (ELISA) was used to characterize the
concentration of VEGF protein present within these samples..." - (correct answer)I, III.
DNA sequencing, Southern blot
-Southern blot: detect a particular sequence of DNA
-DNA sequencing and Southern blotting are ____ assays are used to assess relative
quantity of genes between tissue types.
-Northern blotting is an _____ assay used to assess gene expression in different
tissues. - (correct answer)DNA,
RNA
