Geneticx MB3
With respect to X-chromosome inactivation in females, which, if any, of the following statements is incorrect?
The process involves epigenetic silencing of each gene on one of the two X chromosomes, either the maternal X chromosome or the paternal X chromosome
The term phenotype can be applied to a wide range of manifestations. Which of the following properties, if any, do not constitute a phenotypic manifestation?
The sequence of a person's beta globin gene.
The term phenotype an be applied to a wide range of manifestations. Which of the following properties, if any, do not constitute a phenotypic mutation
The sequence of a persons beta globin gene
With reference to imprinting disorders, which, if any, of the following statements is false?
With the exception of abnormal chromosome segregation, imprinting disorders always result from a deletion or inactivating mutation within, or spanning the imprinted gene cluster.
With respect to X-linked dominant inheritance, which, if any, of the following statements is false?
Each daughter born to an affected father has a risk of 1 in 2 of being affected.
With respect to autosomal recessive inheritance, which, if any, of the following statements is incorrect?
Heterozygotes are always asymptomatic carriers
Which of the following is a disease whose molecular basis is due to the unstable expansion of CAG repeats encoding polyglutamine
Huntington disease
Which of the following amino acid substitutions would be considered to be a conservative substitution if the original amino acid was Arg?
Lysine (Arg), (R)
Gain of function missense mutations in the RET gene which encodes a tyrosine kinase protein result in
Medullary thyroid carcinoma or multiple endocrine neoplasia
With respect to mosaicism, which, if any, of the following statements, is false?
Mosaicism is the inevitable consequence of germline mutations.
With respect to noncoding RNA (ncRNA) , which, if any, of the following statements, is false?
Most regulatory long ncRNAs work as trans-acting regulators
Concerning transport of genes into human (or animal) cells, which, if any, of the following statements is false?
None
Which of the following statements, if any, is false? a) Monoclonal antibodies are made by identical immune cells and so will recognize and bind just one specific epitope on a target molecule. b) Monoclonal antibodies of rodent origin are far from ideal therapeutic agents because of their short half-life in human serum and the potential for immune responses by the recipient. c) Humanized antibodies are hybrid antibodies that have constant regions of human origin but variable regions of rodent origin. d) An intrabody is an artificial constructs with just a single chain that is linked to variable domains and, unlike regular antibodies with four polypeptide chains, has the potential to work inside cells
c) Humanized antibodies are hybrid antibodies that have constant regions of human origin but variable regions of rodent origin.
With respect to histone modifications, which, if any, of the following statements, is true?
histone acetylation always means adding an acetyl group to the side chain of a lysine residue.
With regard to the molecular pathogenesis of facioscapulohumeral dystrophy, which, if any, of the following can be implicated in the pathogenesis?
increased heterochromatin.
Assisted reproductive technology studies modeled in mice have demonstrated
intracytoplasmic sperm injection induces primary epimutations
Which, if any, of the following is incorrect? When used in genetics, the term character
may apply to any intracellular property, such as the sodium ion concentration of a cell or the mitochondrial DNA sequence.
A nonsense mutation would be expected to result in
production of a polypeptide shorter than normally expected
Which, if any, of the following descriptions is false? a) Genomic imprinting in mammals really means that a very few genes are expressed from one allele only, according to the sex of the parent. b) Imprinted genes are often found in clusters of genes, many of which are imprinted. c) means that in a diploid cell two copies of the same chromosome are inherited from one parent d) Within an imprinted gene cluster, all genes on one of the two parental chromosomes are silenced, but the equivalent genes on the other parental chromosome are not subject to silencing.
Within an imprinted gene cluster, all genes on one of the two parental chromosomes are silenced, but the equivalent genes on the other parental chromosome are not subject to silencing
With respect to X-linked recessive inheritance, which, if any, of the following statements is false?
Women are always asymptomatic.
A pathogenic mutation that is unstable at mitosis and meiosis and can result in progressively severe phenotypes
a dynamic mutation
A class of mutation that is quite frequently associated with a gain of function
a missense mutation
A type of mutation that results in genetic mosaicism
a post-zygotic (somatic) mutation
A mutation that does not cause a disease but that is unstable at mitosis and meiosis and can change into pathogenic mutation
a premutation
Regarding chromosome abnormalities, which of the following statements, if any, is false?
a) A Robertsonian translocation is a common example of an aneuploidy. c) Triploidy is most commonly caused by fertilization of an egg by a diploid sperm.
With respect to microRNAs, which, if any, of the following statements, is false?
a) MicroRNA is a generic term that covers all tiny RNAs, ones that are less than 35 nucleotides long when mature. b) MicroRNAs usually work as transcription factors. c) MicroRNAs regulate target genes by binding to complementary sequences on one DNA strand of the target gene. d) MicroRNAs normally regulate the expression of just a single target gene.
With respect to autosomal dominant inheritance in human genetics, which, if any, of the following statements is incorrect?
a) One of the parents of an affected person will be affected. b) Both parents of an affected person may be unaffected, but one of them at least will carry the mutant allele in all of their nucleated cells. d) The term dominant applies equally to the phenotype of affected individuals with one mutant allele (heterozygotes) and individuals with two mutant alleles because in practice the phenotypes are essentially identical.
MicroRNAs are important gene regulators, but the miRNAs are also regulated in turn by other RNAs. Which, if any, of the following classes of RNA are known to contain RNAs that regulate miRNAs?
a) Pseudogene RNA c) Long noncoding RNA d) Circular RNA
Concerning stem cells, which of the following statements is incorrect?
a) Stem cells occur frequently in our bodies.
Which, if any, of the following is incorrect? When used in human genetics, the term hemizygous is a property that
a) applies to all loci on the X chromosome in males. c) applies to loci on mitochondrial DNA because they are exclusively maternally inherited
Which, if any, of the following is incorrect? When used in human genetics, the term allele
a) describes any individual gene variant. b) refers to a nuclear gene at a locus on a single chromosome
Which of the following descriptions, if any, is false? A person's ability to absorb or metabolize a drug that is intended to treat a genetic disorder
a) is entirely due to genetic factors. c) is not modified by having a bacterial infection. d) is independent of a person's diet.
Depending on the base position within as codon, the percentage of base changes that alter the interpretation of the codon vary remarkably. Which of the following statements, if any, is true?
b) 100% of all possible changes to the second base cause an altered interpretation for the codon. c) About 30% of all possible changes to the third base cause an altered interpretation for the codon.
Which, if any, of the following can be classified as a type of augmentation therapy?
b) A bone marrow transplant. d) Insulin treatment in diabetes.
Purifying selection results in which of the following
removes harmful alleles from the population
Which, if any, of the following is incorrect when used in human genetics,
the terms dominant and recessive apply equally to alleles and phenotypes
Which, if any, of the following is incorrect? When used in human genetics
the terms dominant and recessive apply equally to alleles and phenotypes
With respect to epimutations, which, if any, of the following statements, is false, from a practical viewpoint?
A "chromatin disease" is a disorder that is consistently caused by a primary epimutation.
Interpret the folowing chromosome: 46,XX,del(15)(q11q13)
A female with an interstitial deletion on the long arm of chromosome 15 with breakpoints at q11 and q13
Which, if any, of the following statements is false? a) Gain-of-function mutations are often missense mutations. b) A missense mutation that has a dominant-negative effect can often produce a greater loss of protein function than a null mutation. c) Pathogenic gain-of-function and loss-of-function mutations in the same gene produce different phenotypes . d) A mutant protein that antagonizes the wild type protein produced from the normal allele is known as a hypomorph.
A mutant protein that antagonizes the wild type protein produced from the normal allele is known as a hypomorph.
Which, if any, of the following is not regularly an epigenetic phenomenon that depends on DNA methylation or chromatin modification?
A position effect in which a gene is silenced by an inversion where both breakpoints occur within a euchromatic environment.
With respect to how miRNAs work, which, if any, of the following statements, is false?
A single miRNA normally binds to transcripts from just one target gene
In cystic fibrosis, the p.Phe580del mutation leads to
Aberrant protein folding, leading to protein miss-folding and improper cellular localization
Concerning the efficacy of small molecule drugs, which, if any, of the following statements is true?
At the level of clinical trials drugs can vary widely in how effective they are.
Which of the following nomenclature delineates a reciprocal translocation
46,XX,t(2;6)(q35;p21.3)
Which of the following autosomal trisomies are not compatible with life
46XY+16
Which of the following is a disease whose molecular basis is an unstable expansion of short noncoding tandem repeats
Fragile X syndrome
What type of stain is traditionally used to visualize metaphase chromosomes in preparing a karyotype?
Giemsa
Which, if any, of the following descriptions is false? 8 Uniparental disomy a) means that in a diploid cell two copies of the same chromosome are inherited from one parent. b) is very rare. c) can be the outcome of a trisomic zygote that is unstable and ejects a chromosome from one parent, but keeps two copies of the same chromosome from the other parent. d) can occur when a sperm fertilizes an egg that lacks one chromosome, and the resulting unstable zygote is able to recover by duplicating the single chromosome.
None.
Which, if any, of the following statements is true? a) Autologous cell transplantation is involved in in vivo gene therapies: cells from an individual are genetically modified and then returned to that individual. b) Adenovirus vectors have the advantage that they offer very high level expression and are well suited to gene therapy for blood disorders. c) Adenovirus vectors have a better safety profile than adeno-associated virus vectors and have a larger insert size capacity. d) Adeno-associated virus vectors are well suited to gene therapy for blood disorders but have a low insert size capacity
None.
With respect to mitochondrial inheritance, which, if any, of the following statements is false? a) Affected individuals can be of either sex. b) Mitochondrial disorders are transmitted virtually exclusively through the maternal line. c) Both the sperm and the egg contribute mitochondrial DNA to the zygote. d) Clinical variability is a common feature of mitochondrial DNA disorders.
None.
With respect to the DNA methylation mechanism in mammalian cells, which of the following statements, if any, is true?
None.
With regard to drug metabolism, which, if any, of the following statements, is true? a) The therapeutic window is simply the range of plasma drug concentrations in which the drug has therapeutic benefit. b) Each individual drug molecule is metabolized by a specific drug-metabolizing enzyme that is dedicated to the metabolism of that drug. c) An ultrafast metabolizer is a person who metabolizes a drug too quickly and so is at risk of an overdose d) A poor metabolizer is a person who cannot metabolize a drug properly and is at risk of an underdose.
None. All are false
Which of the following is a disease whose molecular basis is caused by a gene-pseudo gene sequence exchange
Steroid 21-hydroxylase deficiency
Regarding mutations, which of the following statements, if any, is false? a) A de novo mutation is one that has occurred post-zygotically. b) Each of us has multiple genes where both the maternal and paternal alleles have inactivating mutations. c) The vast majority of mutations in our DNA do not adversely affect gene expression. d) The mitochondrial genome has a very high gene density and accordingly the mutation frequency in mtDNA is low.
a) A de novo mutation is one that has occurred post-zygotically. d) The mitochondrial genome has a very high gene density and accordingly the mutation frequency in mtDNA is low.
With respect to microRNAs, which, if any, of the following statements, is false?
a) A microRNA normally works by binding to perfectly complementary sequences within an RNA transcript, usually an mRNA. d) A nuclear endoribonuclease called dicer cleaves the miRNA precursor so that it forms a stem-loop RNA
With regard to treatment of inborn errors of metabolism (IEM), which of the following statements, if any, is false?
a) IEMs are all single gene disorders that have been studied for many decades, leading to the development of successful treatment in all cases.
Which, if any, of the following statements is incorrect? a) In X-chromosome inactivation the inactivated X chromosome is epigenetically silenced by a transcript, the XIST RNA, that is produced from the active X chromosome. b) The XIST RNA works by coating most of the X chromosome that is to be inactivated and then recruiting Polycomb proteins to condense the chromosome. c) The inactivated X chromosome carries the kinds of histone modification that are typical of heterochromatin. 9 d) The pattern of X-chromosome inactivation is made randomly but once it has been established the same pattern of X-inactivation is propagated through all mitotic and meiotic cell divisions.
a) In X-chromosome inactivation the inactivated X chromosome is epigenetically silenced by a transcript, the XIST RNA, that is produced from the active X chromosome. d) The pattern of X-chromosome inactivation is made randomly but once it has been established the same pattern of X-inactivation is propagated through all mitotic and meiotic cell divisions.
With respect to microRNAs, which, if any, of the following statements, is true?
a) MicroRNA genes often occur in gene clusters within introns of protein-coding genes and are usually transcribed by RNA polymerase II. b) Like an mRNA a miRNA is initially produced as a larger precursor RNA that, like the great majority of mRNAs, usually has a 5' cap and a poly(A) tail. d) An miRNA is initially produced as a duplex RNA but in order to work it needs to be converted into a single-strand RNA.
With respect to X-chromosome inactivation, which, if any, of the following statements are not correct ?
b) In humans all diploid cells that carry two normal X-chromosomes are subject to a random pattern of X-inactivation. d) The inactivated X chromosome becomes a highly condensed Barr body in which genes are silenced across the length of the chromosome.
Concerning gene transfer into human cells, which, if any, of the following statements is false?
b) Most integrating viruses insert their DNA into a specific location within the genome. d) Because non-integrating viruses cannot insert their DNA into the chromosomes of a cell, the transduced DNA is quickly destroyed by enzymes within the host cell.
Concerning making animal models of human disease, which, if any, of the following statements is false?
b) Pronuclear microinjection is best suited to modelling recessively inherited single gene disorders. d) Gene targeting using embryonic stem cells in mice is a popular way of modelling disease phenotypes that result from a gain-of-function.
Concerning animal models of human disease, which, if any, of the following statements is false?
b) Rats have been the preferred disease models because they offer the best balance between rapid breeding, size and the cost of maintaining colonies. c) Rodent models are especially suited to modelling neuropsychiatric disorders.
An individual single gene disorder can show different levels of genetic heterogeneity, and different mutations in a single gene can sometimes result in a very wide range of different phenotypes. Which, if any, of the following statements, is false?
b) Sickle cell anemia is an outstanding example of allelic heterogeneity. c) Locus heterogeneity means that a disease phenotype is manifest only as a result of the additive contributions of genetic variants at multiple loci.
Which, if any, of the following statements is true? a) A person is said to be a chimera if he or she has two or more genetically different cells. b) The diversity of immunoglobulins made by a person is due to genetic mosaicism. c) Having cells that inactivate the paternal X and cells that inactivate the maternal X is an example of genetic mosaicism in female mammals. d) A person with cell populations that are genetically different because they originated from two different zygotes is described as a genetic mosaic.
b) The diversity of immunoglobulins made by a person is due to genetic mosaicism
Which, if any, of the following statements is false? a) The great majority of clinical gene therapy trials have had limited success b) The only successful gene therapies have been for recessive blood disorders. 9 c) The only successful gene therapies have been ex vivo gene therapies. d) Gene therapy for inherited disorders represents a minority of clinical gene therapy trials.
b) The only successful gene therapies have been for recessive blood disorders. c) The only successful gene therapies have been ex vivo gene therapies.
Concerning disorders resulting from unstable expansion of tandem oligonucleotide repeats, which, if any of the following statements is false
b) The repeats are of a variable number of nucleotides (from three to six) in both coding DNA and noncoding DNA. d) The expanded arrays in noncoding DNA always result in loss of function of the host gene or of a neighboring gene.
Which, if any, of the following statements is false? a) Genome editing means making a predetermined change to the nucleotide sequence at just one locus within an intact cell. b) The specificity of genome editing depends on an initial site-specific cleavage of double stranded DNA following base pairing with specifically designed nucleotide sequences. 10 c) Genome editing has the potential to permit specific "gene correction" in which a mutant sequence in a cell is restored to the normal sequence. d) Genome editing might also have therapeutic potential by specifically inactivating a gene in some cases.
b) The specificity of genome editing depends on an initial site-specific cleavage of double stranded DNA following base pairing with specifically designed nucleotide sequences.
Which, if any, of the following descriptions is false? a) Zinc fingers are elements of protein secondary structure in which the polypeptide chain folds back upon itself after co-ordination of a Zn2+ ion with selected amino acids, often a pair of cysteines and a pair of histidines. b) Zinc finger nucleases are natural proteins containing a sequence of zinc fingers that can bind to specific sequences in DNA. c) After zinc finger nucleases bind to both DNA strands at a specific DNA sequence they attract cellular DNA cleavage enzymes, inducing them to make a double-stranded break at just that one position in the genome. d) The CRISPR-Cas system also allows genome editing but in this case the target DNA sequences are recognized by guide RNA sequences rather than proteins.
b) Zinc finger nucleases are natural proteins containing a sequence of zinc fingers that can bind to specific sequences in DNA. c) After zinc finger nucleases bind to both DNA strands at a specific DNA sequence they attract cellular DNA cleavage enzymes, inducing them to make a double-stranded break at just that one position in the genome.
Which, if any, of the following is incorrect? When used in human genetics, the term heterozygote
b) consistently applies to Y-specific loci because men must be heterozygotes at these loci, having a very different sequence on the X chromosome. d) does not apply to loci on the X chromosome in women because in each of a woman's cells one X chromosome is inactivated.
With respect to CpG islands in our genomic DNA, which, if any, of the following descriptions do not apply?
b) long DNA sequences (typically from 10 kb to 100 kb in length). c) low CG dinucleotide frequency.
Which of the following statements, if any, is false? a) Gene therapy involves the direct genetic modification of the cells of a person (or animal model) to achieve a therapeutic goal. b) Current gene therapy is directed at modifying somatic cells. c) The only successful gene therapies are those in which cells are removed from a patient, genetically modified, and then returned to the patient. d) Gene therapy successes have largely involved treatment of recessively inherited disorders.
c) The only successful gene therapies are those in which cells are removed from a patient, genetically modified, and then returned to the patient.
Which, if any, of the following statements is false? a) Hematopoietic stem cells are multipotent because they can give rise to a variety of different cell types. b) Mammalian embryonic stem cell lines are pluripotent because they can give rise to all types of cell in the body. c) Transdifferentiation is a type of epigenetic reprogramming in which a differentiated cell is induced to become pluripotent. d) A transit amplifying cell is a cell produced by asymmetric division of a stem cell and has the potential to give rise to differentiated cells.
c) Transdifferentiation is a type of epigenetic reprogramming in which a differentiated cell is induced to become pluripotent.
Which, if any, of the following statements is false? a) Transdifferentiation means reprogramming of a differentiated cell so that it acquires the characteristics of another type of differentiated cell. b) In dedifferentiation a differentiated cell is artificially reprogrammed so that it behaves as a pluripotent cell. c) Human induced pluripotent stem (iPS) cell lines are usually generated by artificial dedifferentiation of readily accessible human cells, such as skin cells. 8 d) Human iPS cell technologies do not offer clinical applications but they are of value for studying pathways of cellular differentiation
d) Human iPS cell technologies do not offer clinical applications but they are of value for studying pathways of cellular differentiation
Which, if any, of the following statements is false? a) RNA interference (RNAi) is a cellular defense mechanism that is triggered by the presence in cells of unnatural double-stranded RNA, as can occur after viral infections. b) RNAi therapy is a type of RNA-targeted therapy in which specific double-stranded RNA constructs are engineered to appear in diseased cells in order to incite the cells to destroy any RNA that contains the same sequence. c) By destroying RNAs that are related to a specifically introduced genetic construct, artificial RNAi is effectively a type of gene-specific silencing. d) RNAi therapy is best suited to silencing genes so as to replicate a phenotype caused by loss-of-function mutations.
d) RNAi therapy is best suited to silencing genes so as to replicate a phenotype caused by loss-of-function mutations.
Which, if any, of the following statements is false? a) A null allele is one where the gene has been deleted or received an inactivating mutation causing complete loss of gene function. b) Inactivating point mutations are a common cause of pathogenesis in recessively inherited disorders. c) Inactivating point mutations are a common cause of pathogenesis in dominantly inherited disorders. d) When a gain-of-function allele is known to be pathogenic in a single gene disorder, a heterozygote will always show disease symptoms.
d) When a gain-of-function allele is known to be pathogenic in a single gene disorder, a heterozygote will always show disease symptoms.
Which, if any, of the following descriptions is inaccurate? The epigenome
does not vary between cells of the same type
silent mutation
results in a mutated code that specifies the same amino acid as the original codon