Florida National University Huntingtons Disease Multiple Choice Questions

0.25 PointsHuntington’s disease is caused by a:

1. rare recessive allele.
2. nucleotide triplet repeat.
3. monosomic condition.
4. dominant X-linked allele.
5. deletion of part of chromosome 4.

0.25 PointsIdentify human genetic defects or diseases that are inherited as:A.an autosomal recessive.B.an autosomal dominant.C.an X-linked recessive.

0.25 PointsIn a chromosomal inversion, a segment of a chromosome is:

1. reversed.
2. duplicated.
3. lost.
4. attached to a nonhomologous chromosome.
5. deleted.

0.25 PointsIn fragile X syndrome, the fragile X gene contains a nucleotide triplet that repeats 200-1000 times.

1. True
2. False

0.25 PointsIn genomic imprinting:

1. a gene is imprinted in the progeny, depending upon the phenotype of the parent.
2. the expression of a gene depends on the parental phenotype.
3. a gene is imprinted in the progeny, depending upon the age of the parent.
4. the expression of a gene in the progeny depends upon which parent the gene is inherited from.
5. only dominant traits are expressed.

0.25 PointsIn individuals with cystic fibrosis:

1. the mucus enhances the action of the cilia that line the bronchi.
2. the mucus prevents the growth of dangerous bacteria in the respiratory system.
3. the mucus in the respiratory system is thinner than in unaffected individuals.
4. abnormal mucous secretions occur throughout the body systems.
5. abnormal mucous secretions inhibit infections by bacteria.

0.25 PointsIndividuals who are ____ for sickle cell hemoglobin tend to be ____ resistant to falciparum malaria, but do not experience the effects of sickled red blood cells.

1. homozygous dominant; more
2. homozygous dominant; less
3. homozygous recessive; less
4. heterozygous; more
5. heterozygous; less

0.25 PointsKaryotyping is useful for determining:

1. the number of chromosomes in an individual.
2. the presence of recessive traits.
3. whether or not a specific gene is missing from a chromosome.
4. whether or not gene mutations have occurred.
5. the presence of sickle cell anemia.

0.25 PointsMaternal PKU can result in serious effects in fetuses. This problem occurs because:

1. the fetus is homozygous for PKU and therefore cannot metabolize phenylalanine.
2. the fetus is usually homozygous dominant and therefore has PKU.
3. the mother is heterozygous for PKU and therefore cannot metabolize phenylalanine.
4. the mother is homozygous dominant for PKU and cannot metabolize phenylalanine.
5. the mother is homozygous recessive for PKU and cannot metabolize phenylalanine.

0.25 PointsNearly half of the pregnancies that end in miscarriage have:

1. trisomy of chromosome 21.
2. homozygosity for a recessive lethal allele.
3. major chromosomal abnormalities.
4. Klinefelter syndrome.
5. Down syndrome.

0.25 PointsNondisjunction during mitosis leads to:

1. an individual with a clone of abnormal cells.
2. an individual with all abnormal cells.
3. death of the daughter cells.
4. nonviable sperm.
5. normal daughter cells.

0.25 PointsPersons having an XO karyotype are sterile females. They have ____ syndrome.

1. Turner
2. Klinefelter
3. Down (trisomy form)
4. Phenylketonuria
5. Down (translocation form)

0.25 PointsPolyploidy:

1. may be the result of more than one sperm fertilizing an egg.
2. is not lethal in humans.
3. may be the result of the failure of a chromosome to separate during meiosis.
4. can be due to nondisjunction for a chromosome.
5. is the mechanism of dosage compensation.

0.25 PointsSickle cell anemia and cystic fibrosis are examples of a(n) homozygote advantage. _________________

1. True
2. False

0.25 PointsTay-Sachs disease is a(n) ____ disease that results in blindness, intellectual disability, and death due to ____.

1. sex-linked; the absence of one of the sex chromosomes
2. autosomal recessive; accumulation of lipids in brain cells
3. X-linked; accumulation of acetyltransferases in brain cells
4. autosomal; sickled red blood cells
5. autosomal dominant; accumulation of mucus in the lungs