Genetics test #1 B UPDATED ACTUAL
Exam Questions and CORRECT Answers
Which feature is common among people who have Klinefelter syndrome (47,XXY) or a
karyotype with 47,XXX but not among people who have Down syndrome or Edward syndrome?
A. Severely reduced cognition
B. Cleft palate
C. Tall stature
D. Infertility - CORRECT ANSWER - C. Tall stature
Which single physical feature is most often associated with a 47,XXX karyotype?
A. Infertility
B. Large breasts
C. Female-pattern baldness
D. Height greater than siblings - CORRECT ANSWER - D. Height greater than siblings
What is the risk for a man with a 47,XYY karyotype to produce a child with a 47,XYY
karyotype?
A. 100%
B. 50%
C. 25%
D. 0% - CORRECT ANSWER - B. 50%
Why is the incidence of an extra Y chromosome in the general population unknown?
A. The phenotype is that of a normal male.
B. Most conceptions with 47,XYY are spontaneously aborted.
C. The life expectancy for males with 47,XYY is often short.
D. The majority of males with this sex chromosome abnormality are institutionalized. -
CORRECT ANSWER - A. The phenotype is that of a normal male.
,A male patient is tall and has some gynecomastia along with a low sperm count. During
infertility testing, he was found to have a 47,XXY karyotype. Which disorder is consistent with
these findings?
A. Normal male
B. Turner syndrome
C. Klinefelter syndrome
D. Testicular feminization syndrome - CORRECT ANSWER - C. Klinefelter syndrome
Which health screening activity is most important for girls and women with Turner syndrome?
A. Mammography
B. Test for osteoarthritis
C. Blood pressure screening
D. Pulmonary function testing - CORRECT ANSWER - C. Blood pressure screening
What is the most likely mechanism for a 45,X karyotype?
A. Anticipation
B. Nondisjunction
C. Expansion
D. Heteroplasmy - CORRECT ANSWER - B. Nondisjunction
Which of the following definitions accurately represents the concept of expansion?
A.The phenotype of a genetic condition is expressed with greater severity and at earlier ages with
succeeding generations.
B.The number of trinucleotide repeat sequences within the noncoding region of a specific gene
allele is increased.
C.The number of copies of a specific gene allele is amplified on one chromosome of a
homologous pair.
, D.A specific gene allele has at least two copies of every exon within the gene. - CORRECT
ANSWER - B. The number of trinucleotide repeat sequences within the noncoding region
of a specific gene allele is increased.
What is the function of the FMR1 gene?
A. Promoting brain development and maintaining neuronal synapses
B. Ensuring the expression of all other genes present on the X chromosome
C. Preventing amyloid plaque deposits and formation of neuronal tangles in the brain
D. Maintaining the structural integrity of the histone proteins surrounding the X chromosome -
CORRECT ANSWER - A. Promoting brain development and maintaining neuronal
synapses
At what specific location on an X chromosome is a break most likely to occur in fragile X
syndrome?
A. The centromere
B. End of the p arm
C. End of the q arm
D. Within the nucleosome - CORRECT ANSWER - C. End of the q arm
Which of the following mechanisms in fragile X syndrome (FXS) leads to expression of the
disorder?
A. Trinucleotide repeat sequences interspersed with the exons of the FMR1 gene, resulting in the
production of an abnormal protein
B. Trinucleotide repeat sequences causing methylation of the FMR1 gene, thus silencing its
expression
C. Increased production of microRNA molecules that interfere with the transcription of the
FMR1 gene
D. Increased production of microRNA molecules that interfere with the translation of the FMR1
gene - CORRECT ANSWER - B. Trinucleotide repeat sequences causing methylation of
the FMR1 gene, thus silencing its expression
Which condition or health problem is more common in women who have an FMR1 mutation?
Exam Questions and CORRECT Answers
Which feature is common among people who have Klinefelter syndrome (47,XXY) or a
karyotype with 47,XXX but not among people who have Down syndrome or Edward syndrome?
A. Severely reduced cognition
B. Cleft palate
C. Tall stature
D. Infertility - CORRECT ANSWER - C. Tall stature
Which single physical feature is most often associated with a 47,XXX karyotype?
A. Infertility
B. Large breasts
C. Female-pattern baldness
D. Height greater than siblings - CORRECT ANSWER - D. Height greater than siblings
What is the risk for a man with a 47,XYY karyotype to produce a child with a 47,XYY
karyotype?
A. 100%
B. 50%
C. 25%
D. 0% - CORRECT ANSWER - B. 50%
Why is the incidence of an extra Y chromosome in the general population unknown?
A. The phenotype is that of a normal male.
B. Most conceptions with 47,XYY are spontaneously aborted.
C. The life expectancy for males with 47,XYY is often short.
D. The majority of males with this sex chromosome abnormality are institutionalized. -
CORRECT ANSWER - A. The phenotype is that of a normal male.
,A male patient is tall and has some gynecomastia along with a low sperm count. During
infertility testing, he was found to have a 47,XXY karyotype. Which disorder is consistent with
these findings?
A. Normal male
B. Turner syndrome
C. Klinefelter syndrome
D. Testicular feminization syndrome - CORRECT ANSWER - C. Klinefelter syndrome
Which health screening activity is most important for girls and women with Turner syndrome?
A. Mammography
B. Test for osteoarthritis
C. Blood pressure screening
D. Pulmonary function testing - CORRECT ANSWER - C. Blood pressure screening
What is the most likely mechanism for a 45,X karyotype?
A. Anticipation
B. Nondisjunction
C. Expansion
D. Heteroplasmy - CORRECT ANSWER - B. Nondisjunction
Which of the following definitions accurately represents the concept of expansion?
A.The phenotype of a genetic condition is expressed with greater severity and at earlier ages with
succeeding generations.
B.The number of trinucleotide repeat sequences within the noncoding region of a specific gene
allele is increased.
C.The number of copies of a specific gene allele is amplified on one chromosome of a
homologous pair.
, D.A specific gene allele has at least two copies of every exon within the gene. - CORRECT
ANSWER - B. The number of trinucleotide repeat sequences within the noncoding region
of a specific gene allele is increased.
What is the function of the FMR1 gene?
A. Promoting brain development and maintaining neuronal synapses
B. Ensuring the expression of all other genes present on the X chromosome
C. Preventing amyloid plaque deposits and formation of neuronal tangles in the brain
D. Maintaining the structural integrity of the histone proteins surrounding the X chromosome -
CORRECT ANSWER - A. Promoting brain development and maintaining neuronal
synapses
At what specific location on an X chromosome is a break most likely to occur in fragile X
syndrome?
A. The centromere
B. End of the p arm
C. End of the q arm
D. Within the nucleosome - CORRECT ANSWER - C. End of the q arm
Which of the following mechanisms in fragile X syndrome (FXS) leads to expression of the
disorder?
A. Trinucleotide repeat sequences interspersed with the exons of the FMR1 gene, resulting in the
production of an abnormal protein
B. Trinucleotide repeat sequences causing methylation of the FMR1 gene, thus silencing its
expression
C. Increased production of microRNA molecules that interfere with the transcription of the
FMR1 gene
D. Increased production of microRNA molecules that interfere with the translation of the FMR1
gene - CORRECT ANSWER - B. Trinucleotide repeat sequences causing methylation of
the FMR1 gene, thus silencing its expression
Which condition or health problem is more common in women who have an FMR1 mutation?
