Question 1

A known abnormality in a gene's sequence that can be linked to a genetic disease is called a(n)

Accepted Answer

A)   genetic profile.
B)   enzyme.
C)   genetic marker.
D)   DNA microarray.
E)   genomic DNA.

Question 2

A man with an X-linked recessive trait has a daughter with a woman who does not exhibit the trait. What is/are the possible genotype(s)  of the daughter?

Accepted Answer

A)   XbXb
B)   XBXB
C)   XBXb or XbXb
D)   XBXb
E)   XBXB or XBXb

Question 3

What is/are the possible genotypes of the individual marked with a * on this pedigree if the mode of inheritance is autosomal recessive?

Accepted Answer

A)   AA
B)   AA or Aa
C)   aa
D)   cannot be determined
E)   Aa

Question 4

A person with familial hypercholesterolemia is participating in an ex-vivo gene therapy trial. The procedure involves

Accepted Answer

A)   infecting a portion of the person's liver with a retrovirus containing a normal gene for a cholesterol receptor.
B)   spraying the normal gene for the cholesterol receptor into the nose.
C)   insertion of the cholesterol receptor gene into a virus, then injecting the virus into the person.
D)   removing a piece of the person's liver, infecting it with a retrovirus containing the normal cholesterol receptor gene, and replacing it after treatment.
E)   transplanting a normal liver into the individual.

Question 5

A female child with an unaffected father can exhibit an X-linked recessive disorder.

Accepted Answer

A) True 
 B)False

Question 6

Figure: 
-You are a genetic counselor, and a man with the translocation shown in the figure is your client. He and his partner (who has a normal karyotype)  wish to have children. You explain to him that the probability of having a child with an unbalanced translocation is ______.

Accepted Answer

A)   0%
B)   25%
C)   50%
D)   75%
E)   100%

Question 7

An embryo produced by in vitro fertilization (IVF)  may be tested for genetic disorders prior to implantation. How is this accomplished?

Accepted Answer

A)   Fetal cells are recovered from the mother's blood, and the DNA analyzed with a DNA microarray.
B)   Amniocentesis or chorionic villus sampling is performed, and a karyotype assembled.
C)   A polar body is isolated and its DNA amplified by PCR for analysis by DNA microarray.
D)   A single cell is removed from a 6 to 8-celled embryo, and its DNA analyzed with a DNA microarray.
E)   Blood is drawn from the embryo for genetic marker analysis.

Question 8

Which of the following syndromes is caused by a translocation?

Accepted Answer

A)   Alagille syndrome
B)   invdup 15 syndrome
C)   Williams syndrome
D)   Cri-du-chat syndrome
E)   Turner syndrome

Question 9

Inversions are chromosomal mutations that

Accepted Answer

A)   always result in a syndrome.
B)   neither increase nor decrease the amount of genetic material in the cell.
C)   rarely cause deletions or duplications during gamete formation when crossing-over occurs.
D)   result from duplication of a portion of a chromosome.
E)   never disrupt gene regulation or cause physical abnormalities.

Question 10

A translocation chromosomal mutation is the exchange of segments between two homologous chromosomes.

Accepted Answer

A) True 
 B)False

Question 11

Chromosome 7 may lose an end piece resulting in Williams syndrome. This is an example of a(n)

Accepted Answer

A)   inversion.
B)   duplication.
C)   deletion.
D)   translocation.
E)   epigenetic inheritance.

Question 12

A child with bluish-purple skin is found to lack the enzyme diaphorase and is subsequently diagnosed with which genetic disorder?

Accepted Answer

A)   methemoglobinemia
B)   Duchenne muscular dystrophy
C)   Marfan syndrome
D)   sickle cell disease
E)   color blindness

Question 13

Amniocentesis may be preferred over chorionic villus sampling (CVS)  for karyotyping because

Accepted Answer

A)   CVS takes much longer to obtain a karyotype.
B)   CVS is a more invasive procedure.
C)   amniocentesis has a lower risk of miscarriage than CVS.
D)   amniocentesis can be performed more quickly than CVS.
E)   a larger amount of tissue may be obtained through amniocentesis.

Question 14

Down syndrome could not be treated by gene therapy because

Accepted Answer

A)   scientists do not know which faulty genes cause the syndrome.
B)   Down syndrome is caused by possessing extra copies of genes of an entire chromosome, and adding more genes would not help.
C)   liposomes and nasal sprays cannot be used due to abnormalities in the respiratory tract of Down syndrome individuals.
D)   there are too many genes involved in the syndrome.
E)   the gene therapy treatment could not be performed on an adult individual.

Question 15

Chromosomes for karyotyping are often obtained from a blood sample. Red blood cells, however, cannot be used for this purpose because

Accepted Answer

A)   they are too small.
B)   they lack nuclei.
C)   white blood cells are much more common.
D)   they have abnormal chromosomes.
E)   they are difficult to isolate.

Question 16

A genetic profile includes

Accepted Answer

A)   the location of all known genes in the human genome.
B)   the entire base sequence of an individual's genome.
C)   all of an individual's normal genes.
D)   an individual's complete genotype, including mutations.
E)   all of an individual's genetic markers.

Question 17

A man carrying a translocation may appear normal, but runs the risk of having children with a syndrome because his children

Accepted Answer

A)   may inherit both abnormal chromosomes from the father and would thus carry a deletion.
B)   may inherit one abnormal chromosome with one normal one from the father, and would carry a deletion or duplication.
C)   will inherit one abnormal chromosome from both the mother and father.
D)   may inherit both normal chromosomes from the father and an abnormal one from the mother.
E)   carry the same translocation as the father.

Question 18

Which of the following diseases are caused by an autosomal dominant allele?

Accepted Answer

A)   cystic fibrosis and Marfan syndrome
B)   Marfan syndrome and Huntington disease
C)   Huntington disease and Duchenne muscular dystrophy
D)   alkaptonuria and Huntington disease
E)   sickle cell disease and Marfan syndrome

Question 19

To perform an in vivo gene therapy treatment, cells are removed from the patient's body, normal genes are added to them, and then the cells are returned to the patient's body.

Accepted Answer

A) True 
 B)False

Question 20

If the mode of inheritance for the pedigree shown here is X-linked dominant, what is/are the possible phenotype(s)  of the individual marked with a *? BXB B)  XBXb C)  XbXb D)  XBXB or XBXb E)  cannot be determined" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   XBXB
B)   XBXb
C)   XbXb
D)   XBXB or XBXb
E)   cannot be determined

Exam 13: Genetic Counseling

A known abnormality in a gene's sequence that can be linked to a genetic disease is called a(n)

Correct AnswerverifiedShow Answer

A genetic profile includes

Correct AnswerverifiedShow Answer

A female child with an unaffected father can exhibit an X-linked recessive disorder.

Correct AnswerverifiedShow Answer

Which of the following diseases are caused by an autosomal dominant allele?

Correct AnswerverifiedShow Answer

A person with familial hypercholesterolemia is participating in an ex-vivo gene therapy trial. The procedure involves

Correct AnswerverifiedShow Answer

If the mode of inheritance for the pedigree shown here is X-linked dominant, what is/are the possible phenotype(s) of the individual marked with a *?

Correct AnswerverifiedShow Answer

An embryo produced by in vitro fertilization (IVF) may be tested for genetic disorders prior to implantation. How is this accomplished?

Correct AnswerverifiedShow Answer

A man carrying a translocation may appear normal, but runs the risk of having children with a syndrome because his children

Correct AnswerverifiedShow Answer

To perform an in vivo gene therapy treatment, cells are removed from the patient's body, normal genes are added to them, and then the cells are returned to the patient's body.

Correct AnswerverifiedShow Answer

Figure: -You are a genetic counselor, and a man with the translocation shown in the figure is your client. He and his partner (who has a normal karyotype) wish to have children. You explain to him that the probability of having a child with an unbalanced translocation is ______.

Correct AnswerverifiedShow Answer

Inversions are chromosomal mutations that

Correct AnswerverifiedShow Answer

A man with an X-linked recessive trait has a daughter with a woman who does not exhibit the trait. What is/are the possible genotype(s) of the daughter?

Correct AnswerverifiedShow Answer

What is/are the possible genotypes of the individual marked with a * on this pedigree if the mode of inheritance is autosomal recessive?

Correct AnswerverifiedShow Answer

A translocation chromosomal mutation is the exchange of segments between two homologous chromosomes.

Correct AnswerverifiedShow Answer

Which of the following syndromes is caused by a translocation?

Correct AnswerverifiedShow Answer

A child with bluish-purple skin is found to lack the enzyme diaphorase and is subsequently diagnosed with which genetic disorder?

Correct AnswerverifiedShow Answer

Chromosomes for karyotyping are often obtained from a blood sample. Red blood cells, however, cannot be used for this purpose because

Correct AnswerverifiedShow Answer

Down syndrome could not be treated by gene therapy because

Correct AnswerverifiedShow Answer

Chromosome 7 may lose an end piece resulting in Williams syndrome. This is an example of a(n)

Correct AnswerverifiedShow Answer

Amniocentesis may be preferred over chorionic villus sampling (CVS) for karyotyping because

Correct AnswerverifiedShow Answer

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