Epigenetics and Genetics

A __________ gene is one that produces an effect only in the homozygous state. recessive hemizygous sex-linked dominant

1

A child is diagnosed with cystic fibrosis. History reveals that the child's parents are siblings. Cystic fibrosis was most likely the result of: consanguinity. genomic imprinting. obligate carriers. X-inactivation.

1

A nurse is reviewing the pedigree chart. When checking for a proband, what is the nurse looking for? The person who is first diagnosed with a genetic disease. The codominance. The phenotype of genetic material. The individual who has a disease gene but is phenotypically normal.

1

A patient wants to know the risk factors for Down syndrome. What is the nurse's best response? Pregnancy in women over age 35 Fetal exposure to mutagens in the uterus Family history of Down syndrome Increased paternal age

1

Which genetic test result would indicate Klinefelter syndrome? 47, X 45, X 45, XXY 47, XXY

4

Which percentage of genes are imprinted? 10 25 50 1

4 About 1% of genes are known to be imprinted.

When considering abnormal epigenetic modifications, what factor is currently being viewed as strongly associated with the development of some cancers? Family genetics Emotional coping skills Environmental stressors Lifestyle choices

3

When discussing DNA replication, which enzyme is most important? RNA polymerase Messenger RNA DNA polymerase Transfer RNA

3

Which information would a nurse practitioner include in an educational session on the process of epigenetics? DNA deoxygenation Folate acetylation DNA methylation Folate deacetylation

3

Which of the following disorders is manifested primarily in males? Neurofibromatosis Klinefelter syndrome Muscular dystrophy Cystic fibrosis

3

Housekeeping genes are vital to the function and maintenance of all the body's cells. What characteristic is associated with these genes? They lack encoding histones. Ribosomal RNA genes are absent. They are transcriptionally active. Epigenetic silencing has occurred.

3

Mutations in the encoding of histone-modifying proteins have been shown to influence the development of what congenial condition? Cleft palate Acephalous Heart disease Webbed digits

3

Research has demonstrated that neural stem cells have an impaired ability to differentiate into functional neurons when subjected to: poor oxygenation. insufficient nutrients. ethanol. marijuana.

3

The condition in which an extra portion of a chromosome is present in each cell is called: inversion. reciprocal translocation. partial trisomy. Down syndrome

3

Which statement indicates a correct understanding of mutations? "Mutations always lead to genetic disease." "Mutations will always lead to death of the individual." "Mutations are any inherited alteration of genetic material." "Mutations are enzymes that travel along the DNA."

3

What information should parents be given about the consequences of phenylketonuria (PKU)? High dietary tyramine may help induce enzyme production. PKU is commonly associated with other congenital anomalies. Failure to treat properly results in progressive mental disability. Mental disability is inevitable.

3

What is the diagnosis of a 13-year-old female who has a karyotype that reveals an absent homologous X chromosome with only a single X chromosome present? Her features include a short stature, widely spaced nipples, and a reduced carrying angle at the elbow. Cri du chat syndrome Klinefelter syndrome Turner syndrome Down syndrome

3

A patient, age 9, is admitted to a pediatric unit with Duchenne muscular dystrophy. When planning care, the nurse recalls the patient inherited this condition through a trait that is: X-linked recessive. X-limited. X-influenced. X-linked dominant.

1

Epigenetics is the field of science that evaluates: mechanism of activation and deactivation of genes. changes in underlying DNA sequence. single nucleotide polymorphism development. copy number variant development.

1

The nurse practitioner observes poor muscle tone, short stature, and intellectual disability in the medical history of a 32-year-old patient with leukemia. Which would the health care provider consider as the cause of the findings? Trisomy of chromosome 21 Trisomy of chromosome 16 Aneuploidy of the X chromosome Aneuploidy of the Y chromosome

1

What genetic disorder is the result if an individual possesses an XXY chromosome configuration? Klinefelter Fragile X Turner Down

1

What is a possible reason for increased risk for chromosomal abnormalities with older maternal age? The older ova are more likely to have errors during meiosis Ova are continuously produced thereby increasing the chance of creating defective ova. Ova meiosis is complete by the time a girl is born thereby making them less likely to divide properly. Older ova are more likely to have p53 gene mutations.

1

Which epigenetic modification is the common site for DNA methylation that renders the gene silent during the transcriptional process? Cytosines that are followed by a guanine base Cytosines that are followed by a thymine base Cytosines that are followed by a uracil base Cytosines that are followed by an adenine base

1

Which individual would be identified as having a disease resulting from an autosomal recessive genetic transmission? A female with cystic fibrosis A male with Huntington disease A female with Turner syndrome A male with Klinefelter syndrome

1

Which individual would be identified as having an X-linked recessive disease? A child with Duchenne muscular dystrophy A man with Huntington disease A woman with breast cancer An infant with cri du chat syndrome

1

Which of the following mutations have the most significant effect on protein synthesis? Frameshift mutations Base pair substitutions Silent mutations Intron mutations

1

A woman of advanced maternal age undergoes genetic testing during her pregnancy. If the fetus has Down syndrome, how many chromosomes would the test identify? 47 47 45 23

1 23 is the normal number of chromosomes seen in sex cells (ova and sperm). 45 chromosomes would indicate a missing chromosome and can be the cause of chromosomal diseases other than Down syndrome. 46 is the normal number of chromosomes seen in cells. 47 The typical child with Down syndrome has 3 copies of the 21st chromosome, which results in a total of 47 chromosomes found in each cell.

A newborn child is noted to have malodorous, musty urine and later shows signs of developmental delay and seizures. Which disorder presents with these characteristics? Phenylketonuria Muscular Dystrophy Sickle Cell Marfan Syndrome

1 Sickle cell causes painful crises, avascular necrosis, and anemia. Phenylketonuria leads to buildup of toxic phenylalanine. This can be neurotoxic, causing brain damage, developmental delay, and seizures. There is also a characteristic musty odor to the urine. Marfan syndrome presents with long limbs and fingers and potentially serious aortic disease. Muscular dystrophy causes muscle weakness and wasting and cardiomyopathy.

What is the probability of having a child with cystic fibrosis if one parent has the disease and the other is a carrier? 50% 100% 75% 25%

1 This would be the case if both parents were carriers. The probability is 50% because the affected parent will pass on the gene to all children and the other has a 50% chance of passing on the gene. This is the probability of an unaffected child if both parents were carriers. This would be the case if both parents had the disease.

When considering abnormal epigenetic modifications, what factor is currently being viewed as strongly associated with the development of some cancers? Family genetics Lifestyle choices Environmental stressors Emotional coping skills

3

Which statement indicates an accurate understanding of the inheritance characteristics of an individual's autosomal recessive disease? Select all that apply. "Males and females are affected equally." "The disease may be seen in siblings of affected individuals." "The child expressing the genetic phenotype is heterozygous." "Approximately 50% of children express the genetic phenotype." "Parents consistently display the genetic phenotype."

1,2

Which statement(s) indicate a need for correction regarding the concept of epigenetics? Select all that apply. "The diverse physical features associated with genetic modifications include changes in the nucleotide sequence." "Epigenetic modification is a change in the gene expression that is a result of mutations in the DNA." "Epigenetic modification is a contributor for the human diversity of physical features." "Gene regulation by epigenetic processes can occur at the level of either transcription or translation." "Epigenetic mechanisms include chemical modifications to DNA and associated histones."

1,2

Which factors may lead to epigenetic modification? Select all that apply. DNA methylation Gene imprinting Histone modification Warm temperatures during conception

1,2,3

Screening tools that are epigenetically based have shown promise in diagnosing which types of cancer? (Select all that apply.) Breast Bladder Colon Skin Prostate

1,2,3,5

A 70-year-old man and his 45-year-old wife have a child who is found to have a genetic disorder. What signs and symptoms are likely to be seen in this child born to parents of advanced maternal and paternal age? Leukemia Congenital Heart Defects Gowers Sign Visual Problems Hearing Disorders

1,2,4,5

Which probabilities are associated with a man with hemophilia A having a child with a woman who does not have the disease and who is not a carrier? None of his sons will be affected. None of his daughters will be carriers. All of his daughters will be carriers. All of his sons will be affected.

1,3 None of his sons would be affected because they receive only the Y chromosome from him, and all of his daughters will be carriers. All of his daughters will be carriers, and none of his sons would be affected because they receive only the Y chromosome from him.

A child is born with a genetic disorder and is found to have 46 chromosomes. Which type of disorder could have caused the genetic disorder? Select all that apply Autosomal Recessive Disorder Chromosomal Disorder Single Gene Disorder Polygenic Disorder Autosomal Dominant Disorder

1,3,4,5 Polygenic disorders are characterized by changes in multiple genes, but the number of chromosomes remains the normal 46. Single disorders are characterized by changes in one gene, but the number of chromosomes remains the normal 46. Chromosomal disorders usually result in abnormal numbers of chromosomes. Autosomal recessive disorders are characterized by changes in single genes, but the number of chromosomes remains the normal 46. Autosomal dominant disorders are characterized by changes in single genes, but the number of chromosomes remains the normal 46.

When the nurse is teaching the staff about X-linked recessive disorders, which information should the nurse include? (Select all that apply.) The trait is never transmitted from father to son. The trait is seen much more often in females than in males. The gene can be transmitted through a series of carrier females. The trait never skips generations. The gene is passed from an affected father to all his daughters.

1,3,5

Which manifestations can be seen in deletion of a region of the long arm of chromosome 15 that is maternally derived? Select all that apply Severe Intellectual Impairment Hypotonia Ataxia Hypogonadism Seizures

1,3,5 Ataxia, seizures, and severe intellectual impairment can be seen in Angelman's syndrome, which is the result of deletion of a region of the long arm of chromosome 15 that is maternally derived. Short stature, hypotonia, small hands and feet, obesity, mild to moderate intellectual impairment, and hypogonadism can all be seen in Prader-Willi syndrome, which is the result of deletion of a region of the long arm of chromosome 15 that is paternally derived.

Which disorders have a known chromosomal inheritance pattern? Turner Syndrome Marfan Syndrome Edwards Syndrome Fragile X Syndrome Down Syndrome

1,3,5 Examples of chromosomal abnormalities include Down, Turner, and Edwards syndromes. Examples of chromosomal abnormalities include Down, Turner, and Edwards syndromes. Marfan syndrome has an autosomal dominant inheritance pattern. Fragile X syndrome has an X-linked inheritance pattern. Examples of chromosomal abnormalities include Down, Turner, and Edwards syndromes.

Research has provided support for the theory that epigenetic modifications can result from deficient in utero nutrition causing which chronic disease? (Select all that apply.) Cardiovascular disease Asthma Crohn's disease Obesity Diabetes

1,4,5

A DNA strand has a region with the sequence ATCGGAT. Which of the following would be a complementary strand? UAGCCUAG TAGCCTAG TUGCCTUG CGATACGT

2

A couple has three offspring: one child has an autosomal dominant disease trait and the other two children do not have the trait. The father is affected by the autosomal dominant disease, but the mother does not have the disease gene. What is the recurrence risk of this autosomal dominant disease for their next child? 25% 50% 33% Unable to determine

2

A normal male and a female carrier for red-green color blindness want to have children. Given that red-green color blindness is an X-linked recessive trait, what information should be given to the parents? 25% males affected Males mostly affected; females mostly carriers Females mostly affected; no males affected 50% females affected

2

A patient will be receiving stem cells obtained from a donor's blood (allogenic transplant) for leukemia (abnormal white blood cells). These stem cells are categorized as multipotent because they can make: differentiated cells that can become any cell. all types of blood cells. only white blood cells. multiple types of cells in the body.

2

An aide asks the nurse why people who have neurofibromatosis will show varying degrees of the disease. Which genetic principle should the nurse explain to the aide? Penetrance Expressivity Dominance Recessiveness

2

The gradual increase in height among the human population over the past 100 years is an example of: a polygenic trait. a multifactorial trait. crossing over. recombination.

2

What is the most common cause of Down syndrome? Maternal translocations Maternal nondisjunction Paternal nondisjunction Paternal translocations

2

What is the role of inactive MLH1 in the development of some forms of inherited colon cancer? Abnormalities of chromosome 11p15.5 that lead to downregulation of IGF2. DNA damage is left unrepaired. Deletion of a nucleotide repeat in the DUX4 gene. Expansion in the number of cytosine-guanine (CG) dinucleotide.

2

What type of mutation does not change the amino acid sequence and thus has no observable consequence? Frameshift Silent Spontaneous Missense

2

Which genetic abnormality may lead to Angelman syndrome? Presence of active IGF2 gene in a double dose Deletion of part of chromosome 15 inherited from mother Imprinting abnormalities of chromosome 11 Deletion of part of chromosome 15 inherited from father

2

Which information from staff indicates successful teaching by the nurse practitioner about sickle cell disease? Sickle cell disease is most common in people of European descent Sickle cell disease means a person has abnormal hemoglobin S (HB S) Sickle cell disease is solely the heterozygous form Sickle cell disease directly affects leukocytes.

2

Which statement regarding a gene is correct? "Genes are one of the 23 paired strands of genetic material in a nucleus." "Genes are composed of sequences of deoxyribonucleic acid." "Genes are chains of ribonucleic acid." "Genes are sperm and egg cells."

2

Which disease is found to have an abnormal methylation of tumor-suppressor genes as part of the progression? Fragile X Syndrome Barrett's Esophagus Depression Fetal Alcohol Syndrome

2 Abnormal methylation of tumor-suppressor genes is not found in depression, fragile X syndrome, or fetal alcohol syndrome. Abnormal methylation of tumor-suppressor genes is common in the progression of Barrett's esophagus.

An 18-year-old presents with a history of hip pain and is found to have avascular necrosis. Which genetic disorder may be present? Tay-Sachs Disease Sickle Cell Disease Edwards Syndrome Cystic Fibrosis

2 Cystic fibrosis primarily affects the lungs and pancreas. Sickle cell disease is characterized by avascular necrosis, frequent painful crises, and acute chest syndrome. Tay-Sachs disease is a metabolic disorder not associated with avascular necrosis. Edwards syndrome is a chromosomal abnormality associated with severe defects that do not include avascular necrosis.

Which gene is responsible for the increase in tumors seen in Beckwith-Wiedemann syndrome? HNPCC IGF2 MLH1 RB1

2 RB1 is associated with retinoblastoma, not Beckwith-Wiedemann syndrome. Beckwith-Wiedemann syndrome causes increased IGF2, which increases growth and certain tumors. MLH1 is associated with colorectal cancer, not Beckwith-Wiedemann syndrome. Hereditary nonpolyposis colorectal cancer is a form of inherited colon cancer, which is not associated with Beckwith-Wiedemann syndrome.

What is the probability of having a child with cystic fibrosis if one parent has the disease and the other is a carrier? 100% 50% 25% 75%

2 This would be the case if both parents were carriers. The probability is 50% because the affected parent will pass on the gene to all children and the other has a 50% chance of passing on the gene. This is the probability of an unaffected child if both parents were carriers. This would be the case if both parents had the disease.

A newlywed couple has an ultrasound that shows that they are having a boy. Which genetic disorders are more likely in their child? Huntington Disease Hemophilia A Fragile X Syndrome PKU Duchenne Muscular Dystrophy

2,3,5 PKU is an autosomal recessive disease; therefore males and females are equally affected. Hemophilia A is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur. Fragile X syndrome is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur. Huntington disease is an autosomal dominant disease; therefore males and females are equally affected. Duchenne muscular dystrophy is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur.

Which chromosomal abnormalities result in a form of Down syndrome? Select all that apply Monosomy X Translocation Trisomy 21 Trisomy 18 Polysomy X

2,3 Trisomy 21 relates to Down syndrome because there are three chromosomes, rather than the normal two, in the 21 position. Trisomy 18 relates to Edwards syndrome. Down syndrome is most often characterized by three chromosomes, rather than the normal two, in the 21 position. This is also known as trisomy 21. Klinefelter syndrome is characterized by an extra X chromosome, which is also known as polysomy X. Turner syndrome is characterized by only one X chromosome being present, which is also known as monosomy X. Some forms of Down syndrome may have part of a chromosome 21 attached to another chromosome, which is an example of translocation.

Which characteristics can be seen when there is a deletion of a region of the long arm of chromosome 15 that is paternally derived? Select all that apply Seizures Hypotonia Obesity Hypogonadism Short Stature Severe Intellectual Impairment

2,3,4,5 Short stature, hypotonia, small hands and feet, obesity, mild to moderate intellectual impairment, and hypogonadism can all be seen in Prader-Willi syndrome, which is the result of deletion of a region of the long arm of chromosome 15 that is paternally derived. Prader-Willi syndrome is the result of deletion of a region of the long arm of chromosome 15 that is paternally derived. Seizures are not normally seen in Prader-Willi syndrome. Seizures are a prominent feature of Angelman's syndrome. Short stature, hypotonia, small hands and feet, obesity, mild to moderate intellectual impairment, and hypogonadism can all be seen in Prader-Willi syndrome, which is the result of deletion of a region of the long arm of chromosome 15 that is paternally derived. Prader-Willi syndrome is the result of deletion of a region of the long arm of chromosome 15 that is paternally derived is associated with mild to moderate (not severe) intellectual impairment. The same deletion, when inherited from the mother, causes Angelman's syndrome, which does feature severe intellectual impairment.

Which structures are responsible for making DNA more compact?Select all that apply MicroRNAs Protamines Oncomirs Housekeeping Genes Histones

2,4,5

Which structures are responsible for making DNA more compact?Select all that apply Oncomirs Protamines MicroRNAs Histones Housekeeping Genes

2,4,5 Both histones and protamines make DNA more compact, whereas housekeeping genes code for these as well as other products. Oncomirs are miRNAs that stimulate cancer development and progression. MicroRNAs are involved in regulation of transcription and replication. Both histones and protamines make DNA more compact, whereas housekeeping genes code for these as well as other products. Both histones and protamines make DNA more compact, whereas housekeeping genes code for these as well as other products.

Which genetic disorders can be understood using Punnett squares? Polygenic Disorder Single Gene Disorder Chromosomal Disorder Autosomal Dominant Disorder Autosomal Recessive Disorder

2,4,5 Single gene disorders are characterized by changes in one gene and can be understood using Punnett squares. Chromosomal disorders usually result in abnormal numbers of chromosomes and cannot be understood using Punnett squares. Autosomal recessive disorders are characterized by changes in single genes and can be understood using Punnett squares. Autosomal dominant disorders are characterized by changes in single genes and can be understood using Punnett squares. Polygenic disorders are characterized by changes in multiple genes, so they cannot be understood using Punnett squares.

An individual is found to have growth retardation, proportionate short stature, leg length discrepancy, and a triangular face. Which genetic condition would be associated with these characterizations? Prader-Willi syndrome Angelman syndrome Russell-Silver syndrome Beckwith-Wiedemann syndrome

3

During which stage of human development does the role of epigenetics have the greatest impact on the development of epigenetic abnormalities? Puberty Infancy In utero Middle age

3

A child is born with a genetic disorder and is found to have 46 chromosomes. Which type of disorder could have caused the genetic disorder? Select all that apply Chromosomal Disorder Polygenic Disorder Autosomal Dominant Disorder Autosomal Recessive Disorder Single Gene Disorder

2-4 Polygenic disorders are characterized by changes in multiple genes, but the number of chromosomes remains the normal 46. Single disorders are characterized by changes in one gene, but the number of chromosomes remains the normal 46. Chromosomal disorders usually result in abnormal numbers of chromosomes. Autosomal recessive disorders are characterized by changes in single genes, but the number of chromosomes remains the normal 46. Autosomal dominant disorders are characterized by changes in single genes, but the number of chromosomes remains the normal 46.

. __________ syndrome occurs in males when there is an extra X chromosome. Turner Triple X Klinefelter XYY

3

A nurse recalls the basic components of DNA are: codons, oxygen, and cytosine. pentose sugars and four phosphate bases. a phosphate molecule, deoxyribose, and four nitrogenous bases. adenine, guanine, and purine.

3

Which response is most appropriate when the parents (both heterozygotes) of a child born with cystic fibrosis ask the probability of future pregnancies resulting in a child inheriting the disease? 100% 50% 25% 75%

3 A child that inherits an autosomal recessive disorder must receive the affected gene from both parents. Using a Punnett square, the probability can be seen to be 25%. 50% would be the inheritance pattern of an autosomal dominant disease where one parent is affected. 75% would be the probability of having a child who does not have cystic fibrosis. All children born to two parents who have an autosomal recessive disease will have the disease; this would equate to 100% of the offspring

Which type of DNA segment is bound tightly to its associated histones? Chromatin Nucleosomes Heterochromatic Euchromatic

3 Chromatin is the combination of DNA and its associated histones and RNA molecules. A euchromatic segment of DNA is only loosely bound to associated histones. A nucleosome is a set of histones and the segment of DNA wound around them. Heterochromatic segments are bound tightly to their associated histones.

A newly discovered disease features DNA methylation at cytosines outside of the CpG context. Which cells were most likely involved in this disease process? Adult Sex Cells Adult Somatic Cells Embryonic Stem Cells Embryonic Sex Cells

3 DNA methylation in adult sex cells, adult somatic cells, and embryonic sex cells occurs principally at cytosines that are followed by a guanine base (sometimes known as cytosines in "CpG dinucleotides"). In human embryonic stem cells, methylation can occur at cytosines outside of the CpG context.

Which statement describes the circumstances of fragile S-associated primary ovarian insufficiency? Genetic changes cause the phenomenon Neither epigenetic nor genetic changes are present Epigenetic changes are occurring Epigenetic changes are coincidental with genetic changes

4

What is the diagnosis of a 13-year-old female who has a karyotype that reveals an absent homologous X chromosome with only a single X chromosome present? Her features include a short stature, widely spaced nipples, and a reduced carrying angle at the elbow. Down syndrome Cri du chat syndrome Klinefelter syndrome Turner syndrome

4

Which epigenetic mechanisms alter the charges of the histone proteins? Select all that apply Noncoding RNAs MicroRNAs DNA Methylation DNA Hydroxymethylation Genomic Imprinting

3,4

Which diseases are linked to epigenetics? Select all that apply Diabetes Alcoholism Depression Posttraumatic Stress Disorder (PTSD) Autism-Spectrum Disorder Coronary Artery Disease

3,4,5 Diabetes, coronary artery disease, and alcoholism are multifactorial but is not linked to epigenetic factors. Fetal alcohol syndrome, depression, posttraumatic stress disorder (PTSD), and autism-spectrum disorder all have links to epigenetics.

A newlywed couple has an ultrasound that shows that they are having a boy. Which genetic disorders are more likely in their child? PKU Huntington Disease Hemophilia A Fragile X Syndrome Duchenne Muscular Dystrophy

3,4,5 PKU is an autosomal recessive disease; therefore males and females are equally affected. Hemophilia A is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur. Fragile X syndrome is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur. Huntington disease is an autosomal dominant disease; therefore males and females are equally affected. Duchenne muscular dystrophy is an X-linked disease. Because the couple is having a boy, this disease is more likely to occur.

What is the result of homologous chromosomes failing to separate during meiosis? Polyploidy Conjoined twins Neurofibromatosis Nondisjunction

4

Which genetic test result would indicate Klinefelter syndrome? 45, X 45, XXY 47, X 47, XXY

4

A 12-year-old male is diagnosed with Klinefelter syndrome. His karyotype would reveal which of the following? XY XX XYY XXY

4

A 15-year-old female is diagnosed with Prader-Willi syndrome. This condition is an example of: an autosomal recessive trait. a sex-linked trait. an autosomal dominant trait. genomic imprinting.

4

A 20-year-old pregnant female gives birth to a stillborn child. Autopsy reveals that the fetus has 92 chromosomes. What term may be on the autopsy report to describe this condition? Triploidy Aneuploidy Biploidy Tetraploidy

4

A 5-year-old male presents with mental retardation and is diagnosed with Fragile X syndrome. When the parents ask what caused this, the nurse practitioner responds with: mutation in the transmembrane conductance regulator. nondisjunction of chromosome 21 translocation of the Philadelphia chromosome. expansion of cytosine-guanine-guanine (CGG) repeats 200.

4

A biologist is explaining how RNA directs the synthesis of protein. Which process is the biologist describing? Termination Translocation Transcription Translation

4

A cell that does not contain a multiple of 23 chromosomes is called a _____ cell. diploid haploid euploid polyploid

4

A nurse practitioner observes a child with short stature, hypotonia, intellectual disability, and a body mass index of 35. Which would the nurse practitioner identify as the possible syndrome exhibited in the child? Beckwith-Wiedemann syndrome Fragile X syndrome Angelman Russell-Silver syndrome Prader-Willi syndrome

4

A patient, age 9, is admitted to a pediatric unit with Duchenne muscular dystrophy. When planning care, the nurse recalls the patient inherited this condition through a trait that is: X-limited. X-linked dominant. X-influenced. X-linked recessive.

4

The average length of microRNAs (miRNAs) consists of how many nucleotides? 88 11 44 22

4

The base components of DNA are: P, G, C, and T. X, XX, XY, and YY. A, G, C, and U. A, G, C, and T.

4

The gradual increase in height among the human population over the past 100 years is an example of: recombination. crossing over. a polygenic trait. a multifactorial trait.

4

The regions of the heterogeneous nuclear RNA that must be spliced out to form functional RNA are called: anticodon. promoter sites. exons. introns.

4

To express a polygenic trait: penetrance must occur. multiple mutations must occur in the same family. genes must interact with the environment. several genes must act together.

4

An area of the genome that is normally densely methylated is found to be largely devoid of DNA methylation. What would be the effect on expression of the associated genes in this area? There would be a decrease in their expression. Expression would be the same. They would be not expressed at all. There would be an increase in their expression.

4 DNA methylation decreases the expression of genes in an area; it does not completely stop the expression of those genes. Because DNA methylation decreases gene expression, areas where there is less DNA methylation would have an increase in expression. Expression in this scenario would be increased and not the same. There would not be a decrease in expression. There would be an increase because areas largely devoid of DNA methylation are more accessible and able to be expressed.

A newly discovered disease features DNA methylation at cytosines outside of the CpG context. Which cells were most likely involved in this disease process? Adult Somatic Cells Adult Sex Cells Embryonic Sex Cells Embryonic Stem Cells

4 DNA methylation in adult sex cells, adult somatic cells, and embryonic sex cells occurs principally at cytosines that are followed by a guanine base (sometimes known as cytosines in "CpG dinucleotides"). In human embryonic stem cells, methylation can occur at cytosines outside of the CpG context.

Which disease is known to have a strong familial association, attributed to several different genes, and requires early and increased screening? Hemophilia A Marfan Syndrome Cystic Fibrosis Colon Cancer

4 Several genes have been identified that confer an increased risk for colon cancer, so earlier and increased screening may be considered based on history of a first degree relative. As an autosomal recessive disorder, a single gene causes cystic fibrosis, not several genes. As an X-linked recessive disorder, a single gene causes hemophilia A, not several genes. As an autosomal dominant disorder, a single gene causes Marfan syndrome, not several genes.

Which sources are most likely responsible for the presence of large numbers of Tet enzymes in sample cells? Select all that apply Sperm Heart Liver Tumor Embryo

4,5 The heart is an example of an organ that has cells that have already differentiated. Tet enzymes are found around the time of implantation well before organs form. The liver is an example of an organ that has cells that have already differentiated. Tet enzymes are found around the time of implantation well before organs form. The DNA of sperm would be quite tightly packed and therefore not contain an abundance of Tet enzymes. Tet enzymes are known to be responsible for the translocations found in certain types of leukemias. During implantation of the embryo, there is an abundance of methylation loss that is mediated by the Tet enzyme.

Which processes are known as mechanisms of epigenetics? Select all that apply Chromosomal Deletion Hydroxymethylation RNA-Based Mechanisms DNA Methylation Chemical Modifications that Alter the Charges of the Histone Proteins

5 DNA methylation and hydroxymethylation, chemical modifications that alter the charges of the histone proteins, and RNA-based mechanisms are all mechanisms of epigenetics. Chromosomal deletion is responsible for cri du chat syndrome and other disorders, and it is not an example of an epigenetic mechanism because this affects the genotype as well as the phenotype.