Question 1
Question
Biochemistry
Binding of which of the following molecules increases the affinity of hemoglobin for O2?
Question 2
Question
Biochemistry
What does oxygen bind to in myoglobin and hemoglobin?
Answer
-
Fe2+ in the heme
-
Fe3+ in the heme
-
Proximal histidine
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Distal histidine
Question 3
Question
When should you wash your hands rather than use hand sanitizer?
Answer
-
After touching a patient.
-
After taking care of a patient with MRSA.
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After taking care of a patient with clostridia difficile or norovirus.
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After taking care of a patient with tuberculosis.
Question 4
Question
What is the auscultatory gap?
Answer
-
The silent area between the mitral and tricuspid valve areas.
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A gap between the 4th and 5th Korotkoff sounds.
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A year spent abroad listening to hearts.
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A silent gap after the first Korotkoff sounds that may be found in elderly patients, thus giving a falsely low BP reading.
Question 5
Question
Sickle Cell Workshop
What is the molecular base of sickle cell disease?
Answer
-
Lack of expression of the B-globin gene, resulting in the formation of incorrect hemoglobin tetramers
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Point mutation (Glu 6--> Val6) in the B-chain of hemoglobin
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Persistent expression of fetal hemoglobin (HbF)
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Decreased production of a-hemoglobin chains
Question 6
Question
Embryology- Gastrulation
A 25-year old woman gives birth to her first child, after having had prenatal ultrasounds that revealed no obvious defects. However,
the attending physician discovers a small protruding mass extending from the coccyx region (tailbone) that is palpable and may
affect normal defecation. However, the infant appears to have normal neuronal function (no paralysis or spasms) and is otherwise
healthy. What is the most likely cause of this abnormality?
Answer
-
Spina Bifida Occulta
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gastroschisis
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Sacroccygeal teratoma
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Neuroenteric Cyst
Question 7
Question
Embryology: gastrulation
Persistence of which of the following embryonic structures or tissues is MOST likely to give rise to a teratoma on the posterior
surface of the coccyx (tailbone) region?
Answer
-
Lateral plate mesoderm
-
Primitive streak
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Axial mesoderm
-
Neural tube
Question 8
Question
Intro to Histology
Which type of tissue is characterized by considerable extracellular space?
Answer
-
Connective tissue
-
epithelium
-
muscle
-
nervous
Question 9
Question
Intro to Histology
Which type of tissue is characterized by polarized cells with distinct apical and basal surfaces?
Answer
-
connective tissue
-
epithelium
-
muscle
-
nervous
Question 10
Question
Intro to Histology
Why is tissue fixation used in histology?
Answer
-
To attach coverslips to slides
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To bind tissues to microscope slides
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To preserve tissue structure
-
To reduce loss of stain over time
Question 11
Question
Biochemistry
What are enzymes with slightly different molecular structures/sequences but perform identical reactions called?
Answer
-
Holoenzymes
-
Coenzymes
-
Apoenzymes
-
Isoenzymes
Question 12
Question
Enzymes
A drug that is a reversible noncompetitive inhibitor of an enzyme is more potent than a competitive inhibitor because the drug:
Answer
-
Binds and inhibits the reaction whether or not substrate is bound
-
Inactivates the enzyme by forming a covalent bond
-
Is metabolized by the enzyme to a more potent product
-
Prevents substrate binding
Question 13
Question
Enzymes
What effect does an uncompetitive inhibitor have on an enzyme?
Question 14
Question
Enzymes
Many enzymes, membrane transporters, and other proteins can be quickly activated or inactivated by phosphorylation of specific
amino acid residues catalyzed by which of the following?
Answer
-
Kinases
-
Kinesins
-
Proteases
-
Zymogens
Question 15
Question
Enzymes
Hydrolases are a class of enzyme that catalyze reactions involving which of the following?
Question 16
Question
Epidemiology
In a cross-sectional study the reported mean BMI in a sample of 1,024 fourteen-year-old adolescents was 24.2 with a Standard Deviation of 6.4, and a Standard Error of [(6.4)/(Sqrt 1034)] = 6.4/32 = 0.2. Assuming a symmetric distribution, the range of BMIs that
would capture ~95% of fourteen-year-old adolescents in this population is best described by which of the following?
Answer
-
Mean BMI +/- 2*SD = 24.2 +/- 12.8 = (11.4, 37)
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Mean BMI +/- 1*SD = 24.2 +/- 6.4 = (17.8, 30.6)
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Mean BMI +/- 1*SE = 24.2 +/- 0.2 = (24.0, 24.4)
-
Mean BMI +/- 2*SE = 24.2 +/- 0.4 = (23.8, 24.6)
Question 17
Question
Epidemiology
The table from class that compares V02 max in males and females with different characteristics showed that for males, those with recent vigorous physical activity had a V02 max = 47.1 mL/kg/min and those without recent vigorous physical activity had a V02 max = 44.7, with a p-value < 0.001. The correct interpretation of this p-value would be which of the following?
Answer
-
Males with recent vigorous physical activity have a significantly higher V02 max than those who do not have recent vigorous physical activity.
-
The comparison of males with and without vigorous physical activity has such a small p-value that we can be certain that the V02 max values are
different.
-
Males with recent vigorous physical activity have a statistically significantly higher V02 max compared to those without recent vigorous physical
activity.
-
The probability that the null hypothesis is true is well below 0.05 allowing us to reject the null hypothesis.
Question 18
Question
Galactosemia
A 5-month old boy presents in your office with hypoglycemia after eating baby fruits such as strained plums. He has a history of
nausea and vomiting, abdominal discomfort and hypoglycemia after consuming fruit juice or baby fruits. The symptoms are
consistent with hereditary fructose intolerance or aldolase B deficiency. Why does this child with aldolase B deficiency develop low
blood glucose after consumption of fructose?
Answer
-
The accumulation of fructose in the blood stream induces insulin secretion from the pancreas leading to reactive hypoglycemia.
-
High fructose intake that cannot be converted to ATP because of aldolase B deficiency results in reliance on glucose as an energy substrate with
increased glucose uptake into tissue and oxidation to ATP leading to hypoglycemia.
-
Upon exposure to fructose there is an accumulation of fructose 1-phosphate that inhibits glycogen phosphorylase and thus reduces glucose
mobilization from glycogen. Rapid formation of fructose-1-phosphate by fructokinase sequesters inorganic phosphate, which impacts gluconeogenesis
an ATP dependent process.
-
Aldolase B deficiency impairs both fructose and glucose absorption in the intestine which contributes to the hypoglycemia as well as the vomiting
and abdominal discomfort after eating fructose observed with this child.
Question 19
Question
Galactosemia (Gillingham)
A 5-day-old female infant presents with vomiting, diarrhea, bloating, jaundice and failure to thrive. She was 5 lb 2 oz. at birth with
apgar score of 9 and was discharged to home on DOL 2. Mom has been breastfeeding this infant but she has had increasing
symptoms of feeding intolerance and decreased intake. Upon exam, her lens has an oil drop appearance to them. Which of the following is the most likely diagnosis?
Answer
-
Galactokinasedeficiency(GALK)
-
Galactose 1-phosphate uridyl transferase (GALT) deficiency
-
Uridyl diphosphate 4-epimerase (GALE) deficiency
-
Fructose 1,6, biphosphatase deficiency
Question 20
Question
Gastrulation
Which of the following processes requires the formation of the notochord?
Answer
-
Segmentation of the paraxial mesoderm
-
Migration of primitive streak-derived cells into the hypoblast layer
-
Induction of the endocardial heart tubes
-
Induction of the nervous system
Question 21
Question
Glycolysis
For each molecule of glucose, glycolysis results in the net production of which of the following?
Answer
-
4 ADP
-
2 inorganic phosphates
-
2 NADH
-
1 pyruvate
Question 22
Question
Glycolysis
The glycolysis pathway committing step enzyme phosphofructokinase (PFK-1) is inhibited by:
Question 23
Question
Histology
Which chemical compounds found in tissues are stained by the PAS (periodic acid Schiff) method?
Answer
-
Sphingolipids
-
Ceramides
-
Carbohydrates
-
Proteins
Question 24
Question
Imatinib
The fusion of the BCR (breakpoint cluster region) gene with the N-terminus of Abl kinase results in a BCR-Abl kinase fusion protein.
What change in the kinase caused by the fusion event keeps the enzyme constitutively active?
Answer
-
Decreased KM which allows enzyme to remain active at low substrate concentrations
-
Increased catalytic efficiency
-
Loss of a regulatory domain
-
Overproduction of the fusion protein
Question 25
Question
Imatinib (Gleevec) inhibits Abl tyrosine kinase activity by serving as a:
Answer
-
Competitive inhibitor of ATP
-
Competitive inhibitor of tyrosine
-
Non-competitive inhibitor of the enzyme
-
Suicide inhibitor of the enzyme
Question 26
Question
Membranes
The lipid bilayer is formed spontaneously because:
Answer
-
In biological membranes there is a specific ratio of phospholipids and cholesterol.
-
Lipids with two fatty acyl chains of lipids are too bulky to fit into the interior of a micelle
-
The presence of protein in biological membranes facilitates bilayer formation.
-
The acyl chains of lipids are shorter than the acyl chains of detergents.
Question 27
Question
Misfolding
Amyloid formation, the hallmark of several neurodegenerative diseases, is dictated by which of the following ?
Answer
-
Side chain interactions
-
Main chain interactions
-
Hydrophobic interactions
-
pi-pi interactions
Question 28
Question
Misfolding
After exposure to stress such as excessive heat, chaperone proteins function by:
Answer
-
Providing a protective environment in which proteins can fold properly
-
Degrading proteins that have folded improperly
-
Providing a template for how the protein should fold
-
Rescuing proteins that folded incorrectly and allowing them to re-fold into a proper configuration
Question 29
Question
Pentose/Gluconeogenesis
Glucagon is a peptide hormone produced by alpha cells of the pancreas and stimulates which of the following?
Answer
-
Dephosphorylation of phosphofructokinase-2/fructose 2,6-bisphosphatase-2 (PFK-2/FBP-2)
-
Fructose 2,6-bisphosphate synthesis
-
Gluconeogenesis
-
Insulin Synthesis
Question 30
Question
Pentose/Gluconeogenesis (Farrell)
Glucose 6-phosphate dehydrogenase deficiency in the pentose phosphate pathway results in which of the following?
Answer
-
Increased production of glutathione
-
Increased susceptibility to malaria
-
A compulsive need to eat fava beans
-
Hemolytic anemia
Question 31
Question
PyrDH/TCA
Which of the following pathways occurs entirely within the mitochondria?
Question 32
Question
PyrDH/TCA (Farrell)
Pyruvate dehydrogenase activity is inhibited by which of the following?
Question 33
Question
Translation
Please use the attached image to answer the following: After translation initiation, during ongoing protein synthesis, tRNAs carrying an amino acid first bind to the ribosome at which of the sites shown below?
Question 34
Question
Translation (Mayinger)
During translation, the peptidyl transferase catalyzes which one of the following reactions?
Answer
-
Transfer of a phosphate group
-
Amino acid activation
-
Peptide bond formation between adjacent amino acids
-
Binding of ribosome subunits to mRNA
Question 35
Question
Epidemiology
The Iowa Women's Health cohort study examined the relationship between cigarette smoking and the risk (incidence) of different
histological types of lung cancer. For adenocarcinoma, it estimated the annual incidence to be 46/100,000 in light smokers (1-
19/day) with (95% CI: 31, 61). The correct interpretation for this Confidence Interval would be:
Answer
-
We're 95% confident that the true annual Incidence in these women is between 31/100,000 and 61/100,000 per-year).
-
We're 95% confident that the observed annual Incidence is between 31/100,000 and 61/100,000.
-
The probability is 0.95 (95%) that the true annual Incidence in this population is between 31/100,000 and 61/100,000.
-
Because this CI does not include the null value or 1.0, this finding is statistically significant.