UTA Exam 1 UPDATED ACTUAL Exam
Questions and CORRECT Answers
An individual's genetic makeup is referred to as his or her: - CORRECT ANSWER -
~Genotype
An individual's genotype is his or her genetic makeup.
Inserting bone marrow cells into an individual who produces abnormal erythrocytes is an
example of _____ therapy. - CORRECT ANSWER - ~Somatic Cell
Gene therapy can be applied in two ways. The less controversial approach is somatic cell
therapy, which consists of inserting normal genes into the cells of an individual who has a
genetic disease. In the approach, a particular tissue, such as bone marrow cells that produce
abnormal erythrocytes, is treated.
DNA replication requires the enzyme DNA polymerase to: - CORRECT ANSWER -
~Travel along the single DNA strand, adding the correct nucleotide to the new strand.
Rational:
The DNA polymerase enzyme travels along the single DNA strand, adding the correct nucleotide
to the free end of the new strand (see figure 4-2, B).
Transcription is best defined as a process by which: - CORRECT ANSWER - ~RNA is
synthesized from a DNA template.
Rational:
Transcription is the process by which RNA is synthesized from a DNA template. The correct
option is the only one that accurately defines the term transcription.
,The purpose of a staining technique of chromosomes such as Giemsa is to: - CORRECT
ANSWER - ~Allow for the numbering of chromosomes and the identification of
variations.
One of the most commonly used stains is Giemsa stain. By using banding techniques,
chromosomes can be unambiguously numbered, and individual variation in chromosome
composition can be studied. Missing or duplicated portions of chromosomes, which often result
in serious diseases, also can be readily identified.
An amniocentesis indicates a neural tube defect when an increase in which protein is evident? -
CORRECT ANSWER - ~Alpha fetoprotein
Other disorders can be detected with this procedure. These include most neural tube defects,
which cause an elevation of alpha fetoprotein in the amniotic fluid, and hundreds of diseases
caused by mutations of single genes.
An amniocentesis is recommended for pregnant women who: - CORRECT ANSWER -
~Have a family history of genetic disorders
Amniocentesis is recommended only for pregnancies known to have an elevated risk for a
genetic disease or in women older than 30 to 35 years of age.
The most clinically useful technique for prenatal diagnosis of chromosomal abnormalities at 3
months' (12 weeks') gestation is: - CORRECT ANSWER - ~Chorionic villus sampling
Chorionic villus sampling consists of extracting a small amount of villous tissue directly from
the chorion. This procedure can be performed at 10 weeks' gestation and does not require in vitro
culturing of cells; sufficient numbers are directly available in the extracted tissue. Thus the
procedure allows prenatal diagnosis at approximately 3 months' gestation rather than at nearly 5
months' gestation.
The term for an error in which homologous chromosomes fail to separate during meiosis or
mitosis is: - CORRECT ANSWER - ~Nondisjunction
,Aneuploidy is usually the result of nondisjunction, an error in which homologous chromosomes
or sister chromatids fail to separate normally during meiosis or mitosis.
Which clinical manifestations would be expected for a child who has complete trisomy of the
twenty-first chromosome? - CORRECT ANSWER - ~An IQ of 25 to 70, low nasal bridge,
protruding tongue, and flat, low-set ears
Individuals with this disease are mentally retarded, with IQs usually ranging from 25 to 70. The
facial appearance is distinctive and exhibits a low nasal bridge, epicanthal folds (which produce
a superficially Asian appearance), protruding tongue, and flat, low-set ears.
What is the most common cause of Down syndrome? - CORRECT ANSWER - ~Maternal
nondisjunction
Nondisjunction during the formation of one of the parent's gametes or during early embryonic
development occurs in approximately 97% of infants born with Down syndrome. In
approximately 90% to 95% of infants, the nondisjunction occurs in the formation of the mother's
egg cell.
What syndrome, characterized by an absent homologous X chromosome with only a single X
chromosome, exhibits features that include a short stature, widely spaced nipples, and webbed
neck? - CORRECT ANSWER - ~Turner syndrome
In Turner syndrome, a sex chromosome is missing, and the person's total chromosome count is
45. Characteristic signs include short stature, female genitalia, webbed neck, shield-like chest
with underdeveloped breasts and widely spaced nipples, and imperfectly developed ovaries.
A person with 47, XXY karyotype has the genetic disorder resulting in which syndrome? -
CORRECT ANSWER - ~Klinefelter syndrome
A disorder in the chromosome (47, XXY karyotype) results in a disorder known as Klinefelter
syndrome.
, What is the chromosomal variation that causes Klinefelter syndrome? - CORRECT
ANSWER - ~Nondisjunction of X chromosome in the mother
Nondisjunction of the X chromosomes in the mother causes Klinefelter syndrome in the majority
of infants, and the frequency of the disorder rises with maternal age.
What is the second most commonly recognized genetic cause of mental retardation? -
CORRECT ANSWER - ~Fragile X syndrome
Is the second most common genetic cause of mental retardation (after Down syndrome).
What is the blood type of a person who is heterozygous, having A and B alleles as codominant? -
CORRECT ANSWER - ~AB
When the heterozygote is distinguishable from both homozygotes, the locus is said to exhibit
codominance. An example is the ABO blood group, in which heterozygotes having the A and B
alleles express both of them as A and B antigens on their red cells (forming blood group AB).
A couple has two children diagnosed with an autosomal dominant genetic disease. What is the
probability that the next child will have the same genetic disease? - CORRECT
ANSWER - ~One half
Affected heterozygous individuals transmit the trait to approximately one half of their children;
however, because gamete transmission is subject to chance fluctuations, it is possible that all or
none of the children of an affected parent may have the trait. Nevertheless, when large numbers
of matings of this type are studied, the proportion of affected children closely approach one half.
When a child inherits a disease that is autosomal recessive, it is inherited from: - CORRECT
ANSWER - ~Both parents
In most cases of recessive disease, both parents of affected individuals are heterozygous carriers.
Questions and CORRECT Answers
An individual's genetic makeup is referred to as his or her: - CORRECT ANSWER -
~Genotype
An individual's genotype is his or her genetic makeup.
Inserting bone marrow cells into an individual who produces abnormal erythrocytes is an
example of _____ therapy. - CORRECT ANSWER - ~Somatic Cell
Gene therapy can be applied in two ways. The less controversial approach is somatic cell
therapy, which consists of inserting normal genes into the cells of an individual who has a
genetic disease. In the approach, a particular tissue, such as bone marrow cells that produce
abnormal erythrocytes, is treated.
DNA replication requires the enzyme DNA polymerase to: - CORRECT ANSWER -
~Travel along the single DNA strand, adding the correct nucleotide to the new strand.
Rational:
The DNA polymerase enzyme travels along the single DNA strand, adding the correct nucleotide
to the free end of the new strand (see figure 4-2, B).
Transcription is best defined as a process by which: - CORRECT ANSWER - ~RNA is
synthesized from a DNA template.
Rational:
Transcription is the process by which RNA is synthesized from a DNA template. The correct
option is the only one that accurately defines the term transcription.
,The purpose of a staining technique of chromosomes such as Giemsa is to: - CORRECT
ANSWER - ~Allow for the numbering of chromosomes and the identification of
variations.
One of the most commonly used stains is Giemsa stain. By using banding techniques,
chromosomes can be unambiguously numbered, and individual variation in chromosome
composition can be studied. Missing or duplicated portions of chromosomes, which often result
in serious diseases, also can be readily identified.
An amniocentesis indicates a neural tube defect when an increase in which protein is evident? -
CORRECT ANSWER - ~Alpha fetoprotein
Other disorders can be detected with this procedure. These include most neural tube defects,
which cause an elevation of alpha fetoprotein in the amniotic fluid, and hundreds of diseases
caused by mutations of single genes.
An amniocentesis is recommended for pregnant women who: - CORRECT ANSWER -
~Have a family history of genetic disorders
Amniocentesis is recommended only for pregnancies known to have an elevated risk for a
genetic disease or in women older than 30 to 35 years of age.
The most clinically useful technique for prenatal diagnosis of chromosomal abnormalities at 3
months' (12 weeks') gestation is: - CORRECT ANSWER - ~Chorionic villus sampling
Chorionic villus sampling consists of extracting a small amount of villous tissue directly from
the chorion. This procedure can be performed at 10 weeks' gestation and does not require in vitro
culturing of cells; sufficient numbers are directly available in the extracted tissue. Thus the
procedure allows prenatal diagnosis at approximately 3 months' gestation rather than at nearly 5
months' gestation.
The term for an error in which homologous chromosomes fail to separate during meiosis or
mitosis is: - CORRECT ANSWER - ~Nondisjunction
,Aneuploidy is usually the result of nondisjunction, an error in which homologous chromosomes
or sister chromatids fail to separate normally during meiosis or mitosis.
Which clinical manifestations would be expected for a child who has complete trisomy of the
twenty-first chromosome? - CORRECT ANSWER - ~An IQ of 25 to 70, low nasal bridge,
protruding tongue, and flat, low-set ears
Individuals with this disease are mentally retarded, with IQs usually ranging from 25 to 70. The
facial appearance is distinctive and exhibits a low nasal bridge, epicanthal folds (which produce
a superficially Asian appearance), protruding tongue, and flat, low-set ears.
What is the most common cause of Down syndrome? - CORRECT ANSWER - ~Maternal
nondisjunction
Nondisjunction during the formation of one of the parent's gametes or during early embryonic
development occurs in approximately 97% of infants born with Down syndrome. In
approximately 90% to 95% of infants, the nondisjunction occurs in the formation of the mother's
egg cell.
What syndrome, characterized by an absent homologous X chromosome with only a single X
chromosome, exhibits features that include a short stature, widely spaced nipples, and webbed
neck? - CORRECT ANSWER - ~Turner syndrome
In Turner syndrome, a sex chromosome is missing, and the person's total chromosome count is
45. Characteristic signs include short stature, female genitalia, webbed neck, shield-like chest
with underdeveloped breasts and widely spaced nipples, and imperfectly developed ovaries.
A person with 47, XXY karyotype has the genetic disorder resulting in which syndrome? -
CORRECT ANSWER - ~Klinefelter syndrome
A disorder in the chromosome (47, XXY karyotype) results in a disorder known as Klinefelter
syndrome.
, What is the chromosomal variation that causes Klinefelter syndrome? - CORRECT
ANSWER - ~Nondisjunction of X chromosome in the mother
Nondisjunction of the X chromosomes in the mother causes Klinefelter syndrome in the majority
of infants, and the frequency of the disorder rises with maternal age.
What is the second most commonly recognized genetic cause of mental retardation? -
CORRECT ANSWER - ~Fragile X syndrome
Is the second most common genetic cause of mental retardation (after Down syndrome).
What is the blood type of a person who is heterozygous, having A and B alleles as codominant? -
CORRECT ANSWER - ~AB
When the heterozygote is distinguishable from both homozygotes, the locus is said to exhibit
codominance. An example is the ABO blood group, in which heterozygotes having the A and B
alleles express both of them as A and B antigens on their red cells (forming blood group AB).
A couple has two children diagnosed with an autosomal dominant genetic disease. What is the
probability that the next child will have the same genetic disease? - CORRECT
ANSWER - ~One half
Affected heterozygous individuals transmit the trait to approximately one half of their children;
however, because gamete transmission is subject to chance fluctuations, it is possible that all or
none of the children of an affected parent may have the trait. Nevertheless, when large numbers
of matings of this type are studied, the proportion of affected children closely approach one half.
When a child inherits a disease that is autosomal recessive, it is inherited from: - CORRECT
ANSWER - ~Both parents
In most cases of recessive disease, both parents of affected individuals are heterozygous carriers.
