(Inheritance W1) You have received chromosome results back on the products of conception from your patient who has had a miscarriage. The karyotype is designated 92,XXXY. Which term below describes the karyotype?
Haploid
Aneuploid
Triploid
Tetraploid
(Inheritance W1) Polycystic kidney disease is a significant cause of renal failure that presents from early infancy to adulthood. Early-onset cases tend to affect one family member or siblings, whereas adult-onset cases often show a vertical pattern in the pedigree with affected family members in each generation. Which of the following provides the BEST explanation of these observations?
Pleitropy
Variable expressivity
Locus heterogeneity
Allelic heterogeneity
(Cytogenetics W1) A standard chromosome analysis is ordered for a child with heart defects, developmental delay, and an unusual facial appearance. The results are normal. A clinical geneticist colleague with whom you consult suspects Williams syndrome and recommends that fluorescent in situ hybridization (FISH) be performed on the patient's chromosomes using a probe for chromosome 7. Only one signal is seen for the chromosome 7 probe in each chromosome spread examined. Which of the following statements best summarizes the analyses?
A microdeletion is present on one of the patient's chromosomes 7.
This is a normal result.
The initial karyotype results are inconsistent with the FISH results.
FISH is only helpful when the initial karyotype results are abnormal.
(Cytogeneics W1) Which of the following features distinguishes meiosis from mitosis?
Separation of sister chromatids.
DNA replication in preceding interphase
Missegregation of chromosomes, which may lead to aneuploidy.
Synapsis of homologs during prophase I.
(DNA Replication W1) A one-year old child was treated in the emergency department for severe sunburn. According to the parents, the child had minimal sun exposure. No other abnormalities were noted in the physical exam except for freckling. You suspect:
Possible defect in nucleotide excision repair
Parental neglect
Possible defect in DNA mismatch repair
A defect in the process that controls the initiation of DNA replication
(DNA Replication W1) A patient with Xeroderma pigmentosum has a defect in the XPA gene leading to a defect in nucleotide excision repair (NER). Cell extracts are prepared from this patient's cells and tested for the ability to perform nucleotide excision repair on DNA damage resulting from exposure to UV light. What outcome would you predict?
Extracts remove lesions too fast but there is no lasting defect
Cell extracts perform NER within normal limits
Cell extracts cannot repair UV damaged DNA
Exposure to UV light does not result in the specific DNA damage that is repaired by NER
(DNA Replicatoin W1) The replication of genomic DNA is a tightly-controlled fundamental process. The beginning or initiation of chromosomal replication is initiated where?
No proteins are involved in initiation, only DNA is required.
From the centromere of each chromosome
At an origin
At the telomeres
(DNA Replication) Many drugs target the DNA replication process by altering the DNA template, inhibiting crucial enzyme activity, or blocking replication elongation. Drugs that inhibit bacterial Type II Topoisomerases (quinolone related) are very effective in antibacterial chemotherapy. What function of topoisomerase during replication are quinolones targeting?
Unwinding of the Okazaki fragment by the replicative helicase
Resolution of supercoiling created by DNA strand separation by the moving replication fork
Primer loading at the origin of replication by the sliding clamp protein
Loading of the Okazaki fragments in the leading strand
(CSL) In systole, which valves are open and which valves are closed?
Open: mitral, tricuspid; Closed: aortic, pulmonic
Open: pulmonic, tricuspid; Closed: aortic, mitral
Open: aortic, pulmonic; Closed: mitral, tricuspid
Open: aortic, mitral; Closed: pulmonic, tricuspid
(Anatomy) Which type of imaging uses no radiation?
PET scan
CT scan
MRI
Plain X-ray
(Anatomy) Which one of the following types of anatomical planes would divide the body into a left half and a right half?
Sagittal
Horizontal
Frontal
Transverse
(Anatomy) A 15-year-old girl is suspected of having meningitis. To obtain a sample of cerebrospinal fluid by lumbar puncture, the tip of the needle must be placed in which of the following locations?
Between arachnoid mater and dura mater
Between pia mater and arachnoid mater
Deep to pia mater
Superficial to dura mater
(Anatomy) The ventral (anterior) roots of the spinal nerves contain axons of somatic___________?
afferent and somatic efferent neurons
afferent and visceral afferent neurons
afferent neurons
efferent neurons
(Cell Bio) Small unrestrained particles such as proteins in an aqueous solution are in constant riotous motion due to thermal energy. Which of the following is a defining property of thermally-driven Brownian motion in the cell?
The thermally-driven Brownian motion of a protein or protein complex is independent of its mass.
The thermally-driven Brownian motion of a protein or protein complex in the cell results from collisions of the particle with water molecules.
The path of a single protein molecule exhibiting thermally-driven Brownian motion in the cell would fill the cell's volume uniformly in an instant.
The combined paths of millions of protein molecules exhibiting thermally-driven Brownian motion in the cell would eventually fill the cell's volume more or less uniformly.
(Metabolism) During an enzymatically catalyzed reaction, what do the enzymes stabilize?
Product
Substrate
Transition state
Reverse reaction
(Early Embryology) The amniotic cavity first forms by cavitation within which layer of cells?
Extraembryonic mesoderm
Epiblast
Hypoblast
Syncytiotrophoblast
(Embryology) Certain factors delay the transport of the cleavage stage embryo through the uterine tube (oviduct). This delay may cause which of the following?
Extrauterine pregnancy
Failure in fertilization
Failure in zona reaction
Formation of twins
(Embryology) Which of the following types of cells will specifically form the embryo?
Trophoblast
Cytotrophoblast
ICM
Follicle
(Genome organization) What functionally separates neighbouring Topologically Associated Domains (TADs) from each other?
Genes
Boundaries
Enhancers
Segmental duplications
(CSL) A heart murmur is caused by:
Rapid deceleration of blood during early diastole
Rapid deceleration of blood during late diastole
Turbulent blood flow across a valve or septal defect
An inflamed pericardial surfaces rubbing against each other
(Biochem) Please use the attached image to answer the following: Some amino acids have ionizable side chains. Which amino acid would have the titration curve shown in the attached figure?
Alanine
Glycine
Histidine
Leucine
(Biochem) The concentration of H+ ions in a solution at pH 6 compared to pH 7 is:
Twice as high
Twice as low
Ten times higher
ten times lower
(Biochem) Although all protein structures are unique, there are common structural building blocks that are referred to as regular secondary structures. Some proteins have a helices, some have B sheets, and still others have a combination of both. Which of the features below is most responsible for enabling proteins to have these common structural elements?
Specific amino acid sequences
Side-chain interactions
The hydrophobic-core interactions
Hydrogen bonds along the protein backbone
(Genome Organization) The Philadelphia chromosome was a landmark because it was the first consistent chromosome abnormality found in any kind of malignancy. What kind of chromosomal rearrangement creates the Philadelphia chromosome?
inversion
translocation
deletion
duplication
In judging the quality of a physician, which of the following factors is noted as being most important to patients?
The physician's use of advanced medical technology
The physician's amount of time spent on the physical exam of the patient
The physician's ability to build rapport and communicate empathetically
The perceived age and gender of a physician
A physician's active listening is a key part of communication between physician and patient. Active listening includes accurately summarizing the patient's story and responding empathetically. Another indicator of active listening is:
Repeating back the patient's words verbatim to show you have paid careful attention
Paraphrasing the patient's words to demonstrate understanding
To start taking notes right away to show you don't want to miss a word
Immediately opening the patient's EMR to demonstrate you are aware of their history
(Genetic Variation) In reference to genetic variation, a mutation is best characterized as:
A permanent change in the nucleotide sequence or arrangement of DNA, ranging from a single nucleotide to alterations of an entire chromosome
Any change in the DNA sequence which results in disease
An alternate genotype in the population of which the rarer allele has a frequency of at least 1%
Any common variant in the population that increases susceptibility to disease
(Genetic Variation) Your 8 y.o. patient and his parents undergo genome sequencing. The report shows that your patient has a variant, c.100delAG in a gene associated with his phenotype. This variant is not found in either of his parents nor in any population database or the literature. What is your best interpretation?
This is a benign missense variant that, without other evidence, does not explain this patient's clinical presentation.
This is a variant of unknown significance since it has never been reported in a patient.
This is a likely pathogenic missense variant but it requires confirmation by a functional assay
This is a de novo, novel likely pathogenic variant that produces a frameshift and results in disease.
(Inheritance and pedigree) Use the attached image to answer the following: The attached pedigree shows segregation of a rare genetic disease through a family. Filled in symbols represent family members with the disease phenotype. What is the MOST LIKELY mode of inheritance?
AR
AD
XLD
Mitochondrial
(Metabolism) Please use the attached image to answer the following: In the attached graph of an enzyme-catalyzed reaction, what is indicated by the letter "X"?
The change in Gibbs Free Energy, ∆G10
The equilibrium constant, K'eq
The Michaelis-Menton constant, Km
the maximal velocity, Vmax
(Protein Structure) Of the following amino acids, which one can be phosphorylated on its side chain?
alanine
glutamic acid
lysine
tyrosine
(Proteins) Studies conducted with a lysozyme mutant that contains an Asp->Asn change at position 52 and a Glu->Gln change at position 35 exhibited almost a complete loss in enzymatic activity. What is the most likely explanation for the decrease in enzyme activity in the mutant?
Increased affinity for substrate
Absence of negative charges in the active site
Change in the active-site scaffold
Larger amino acids in the active site decreases the affinity for substrate
(Proteins) Polypeptides are synthesized from amino acid building blocks. The condensation reaction between the growing polypeptide chain and the next amino acid to be added involves the combined loss of ________________ from the newly formed peptide.
a water molecule
an amino group
a carbon atom
a carboxylic acid group
(Pedigree) Use the attached image to answer the following: Attached is the pedigree of a family in which a genetic disease is segregating. Affected family members are in black. The MOST LIKELY mode of inheritance is:
XLR
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