Deck 16: Human Genetics and the Human Genome

Question 1

Gene targeting has been used in mice to produce strains that were either homozygous or heterozygous for __________.

A) PKU
B) cystic fibrosis
C) Huntington's disease
D) sickle cell anemia
E) Tays Sachs Disease

Answer 1

B

Question 2

The position of a specific gene on a chromosome can be determined by:

A) preparing a karyotype.
B) southern blotting.
C) genomic hybridization.
D) chromosome sorting.
E) fluorescent in situ hybridization.

Answer 2

E

Question 3

Polyploidy is:

A) the presence of more than two of a certain chromosome.
B) more than two of a certain chromosome.
C) more than one chromosome.
D) the presence of multiple sets of chromosomes.
E) the general term for conditions such as Down or Turner syndrome.

Answer 3

D

Question 4

The normal human karyotype contains __________ chromosomes.

A) 22
B) 23
C) 44
D) 46
E) 54

Question 5

The human genome contains about __________ genes.

A) 25,000
B) 45,000
C) 60,000
D) 80,000
E) 120,000

Question 6

An individual who inherited the specific chromosome __________ deletion from the __________ would most likely have Prader-Willi syndrome rather than Angelman syndrome.

A) 15; mother
B) 15; father
C) 21; mother
D) 21; father
E) 12; father

Question 7

Karyotyping is useful for determining:

A) the number of chromosomes in an individual.
B) if recessive traits are present.
C) if a specific gene is missing from a chromosome.
D) if gene mutations have occurred.
E) the presence of sickle cell anemia.

Question 8

Figure 16-2
Use the figure to answer the corresponding question(s).
In genomic imprinting:

A) a gene is imprinted with the phenotype of the parent, passing it to a progeny.
B) the expression of a gene depends on the parental phenotype.
C) a gene is imprinted with the age of the parent, passing it to the progeny.
D) the expression of a gene depends on which parent it is inherited from.
E) is a place where a part of a chromatid is attached to a chromosome

Question 9

Human genetics can be effectively studied using:

A) offspring raised under controlled conditions.
B) experimental matings between true-breeding strains.
C) controlled matings.
D) population studies of large extended families.
E) population studies of small extended families.

Question 10

Figure 16-2
Use the figure to answer the corresponding question(s).
Refer to Figure 16-2.Based on the phenotypes of the third generation, the genotype of the father in the second generation must be:

A) homozygous for albinism.
B) heterozygous for hair color.
C) heterozygous for albinism.
D) X-linked.
E) dominant.

Question 11

Comparing the human and mouse genomes has revealed that

A) the mouse and human share few genes.
B) the mouse and human genomes are identical.
C) the mouse and human genomes have no genes in common.
D) the mouse and human share most genes.
E) the mouse and human genomes have identical noncoding DNA

Question 12

Figure 16-2
Use the figure to answer the corresponding question(s).
The genotypes of the normal females in the second generation in Figure 16-2 are:

A) homozygous for albinism.
B) heterozygous for hair color.
C) heterozygous for albinism.
D) X-linked.
E) unknown.

Question 13

Polyploidy:

A) may be the result of more than one sperm fertilizing an egg.
B) is not lethal in humans.
C) may be the result of the failure of a chromosome to separate during meiosis.
D) can be due to nondisjunction for a chromosome.
E) is the mechanism of dosage compensation

Question 14

About what percentage of the human DNA codes for polypeptides?

A) 2%
B) 5%
C) 8%
D) 50%
E) 86%

Question 15

The Human Genome Project accomplishes all of the following except:

A) sequencing the entire human genome.
B) identifying all of the genes in the human genome.
C) the foundation for studying gene function in humans.
D) basis for studying variations in gene sequences related to illness.
E) imprinting a gene with the phenotype of the parent

Question 16

Autosomal aneuploidies arise by:

A) chromosome breakage and rejoining.
B) nondisjunction.
C) errors in crossing-over.
D) mistakes in chromosome replication.
E) mutations.

Question 17

Aneuploidies describe:

A) a phenomenon that only occurs in plants.
B) a condition in which an extra chromosome is present or one is absent.
C) a defect that is always fatal in humans.
D) an uncommon condition in humans.
E) mutations that almost always have a beneficial effect on an individual.

Question 18

Figure 16-2
Use the figure to answer the corresponding question(s).
The inheritance pattern demonstrated by the pedigree in Figure 16-2 is:

A) autosomal recessive.
B) autosomal dominant.
C) X-linked recessive.
D) X-linked dominant.
E) unknown from these data.

Question 19

Colchicine is a drug that:

A) arrests cells in mitotic telophase.
B) stimulates meiosis.
C) prevents DNA replication.
D) arrests cells in mitotic metaphase.
E) prevents cells from entering prophase.

Question 20

The normal human karyotype contains __________ autosomes.

A) 22
B) 23
C) 44
D) 46
E) 54

Question 21

Persons having an XO karyotype are sterile females.They have __________ syndrome.

A) Turner
B) Klinefelter
C) Down (trisomy form)
D) Phenylketonuria
E) Down (translocation form)

Question 22

Why are most infants with phenylketonuria usually healthy at birth?

A) The defect causing the condition has usually been repaired by that time.
B) The mother breaks down phenylalanine for both herself and her fetus.
C) The infant can produce sufficient quantities of the enzymes needed by birth.
D) Phenylalanine can be completely excreted in infants.
E) Phenylalanine is completely metabolized in infants.

Question 23

Down syndrome is an example of a __________ condition.

A) monosomic
B) disomic
C) trisomic
D) polyploid
E) transgenic

Question 24

Which of the following statements concerning Down syndrome is FALSE?

A) Down syndrome involves nondisjunction.
B) Down syndrome individuals have 47 chromosomes per somatic cell.
C) Down syndrome incidence increases with increasing material age.
D) Down syndrome individuals have an extra chromosome 22.
E) Down syndrome is variable in expression.

Question 25

In a chromosomal inversion a segment of a chromosome is:

A) reversed.
B) duplicated.
C) lost.
D) attached to a nonhomologous chromosome.
E) deleted

Question 26

Persons having an XXY karyotype are nearly normal males but produce few or no sperm.They have __________ syndrome.

A) Turner
B) Klinefelter
C) Down (trisomy form)
D) Phenylketonuria
E) Down (translocation form)

Question 27

A karyotype reveals that an individual is XYY.Based on your knowledge of human genetics you correctly conclude that this individual is phenotypically __________ and __________.

A) female; with criminal tendencies
B) female; sterile
C) female; fertile
D) male; sterile
E) male; fertile

Question 28

Which of the following are inborn errors of metabolism?

A) PKU and alkaptonuria
B) sickle cell anemia and hemophilia
C) cystic fibrosis and Tay-Sachs disease
D) Huntington's disease and fragile X syndrome
E) cri-du-chat syndrome and Down syndrome

Question 29

Which of the following abnormalities is most likely to be lethal to a cell?

A) X chromosome monosomy
B) Y chromosome disomy
C) X chromosome trisomy
D) autosomal trisomy
E) autosomal monosomy

Question 30

Autosomal monosomy is not seen in live births because:

A) its effects are so small as to be overlooked.
B) its effects do not set in until adulthood.
C) its effects are so lethal as to cause spontaneous abortion early in pregnancy.
D) it only occurs in sex chromosomes and therefore does affect nonreproductive function.
E) they lead to the establishment of a clone of abnormal cells

Question 31

Which of the following statements about fragile X syndrome is not correct?

A) It results in learning and attention disabilities in males.
B) It results in hyperactivity in males.
C) The location of the fragile X site is exactly the same in all of an individual's cells.
D) It results in the formation of shorter-than-normal sequences of CGG.
E) Females are usually heterozygous and are therefore more likely to have a normal phenotype.

Question 32

A fragile site

A) is found only on the X chromosome.
B) occurs in only one of the sister chromatids.
C) is associated with cancerous cells.
D) is usually not inherited.
E) is the result of genomic imprinting

Question 33

Nondisjunction during mitosis leads to:

A) an individual with a clone of abnormal cells.
B) an individual with all abnormal cells.
C) death of the daughter cells.
D) nonviable sperm.
E) normal daughter cells.

Question 34

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

A) the fetus is homozygous for PKU and therefore cannot metabolize phenylalanine.
B) the fetus is usually homozygous dominant and therefore has PKU.
C) the mother is heterozygous for PKU and therefore cannot metabolize phenylalanine.
D) the mother is homozygous dominant for PKU and cannot metabolize phenylalanine.
E) the mother is homozygous recessive and cannot metabolize phenylalanine.

Question 35

Turner syndrome is an example of a __________ condition.

A) monosomic
B) disomic
C) trisomic
D) polyploid
E) fragile site

Question 36

Translocation occurs when:

A) part of a chromosome breaks off and attaches to a nonhomologous chromosome.
B) part of a chromosome breaks off and attaches to a homologous chromosome.
C) crossing-over events occur.
D) genes move from one area on a chromosome to another area on the same chromosome.
E) a Y chromosome replaces an X chromosome in a female cell.

Question 37

Aneuploidies for the sex chromosomes are more viable because:

A) they carry less information than most chromosomes.
B) of a lack crossing-over between the X and the Y.
C) they are smaller than most chromosomes.
D) their information is carried on other chromosomes.
E) of dosage compensation.

Question 38

Cri du chat syndrome arises from:

A) trisomy for chromosome 5.
B) deletion of part of chromosome 5.
C) a 14/21reciprocal translocation.
D) nondisjunction.
E) a duplication of part of chromosome 15.

Question 39

Nearly half of the pregnancies that end in miscarriage have:

A) trisomy of chromosome 21.
B) homozygosity for a recessive lethal allele.
C) major chromosomal abnormalities.
D) Klinefelter syndrome.
E) Down syndrome.

Question 40

The sperm in the figure below were most likely produced by:

A) nondisjunction.
B) mutation.
C) X-linkage.
D) translocation.
E) normal meiosis.

Question 41

Huntington's disease is caused by:

A) a rare recessive allele.
B) a repeat of a nucleotide triplet in a gene.
C) a monosomic condition.
D) a dominant X-linked allele.
E) a deletion of part of chromosome 4.

Question 42

Which of the following correctly represents the probability that a detrimental autosomal recessive allele will actually be expressed in a population if the occurrence of the allele is such that 1 in 50 individuals are heterozygous?

A) 1/50 * 1/50 = 1/2500, with 1/4 of their children homozygous recessive = 1/2500 * 1/4 = 1/10,000.
B) 1/50 * 1/4 that are homozygous recessive = 1/200.
C) 1/50 * 2 children (on average) * 1/4 that are homozygous recessive = 1/100.
D) 1/50 * 2 parents * 4 children * 1/4 that are homozygous recessive = 1/25.
E) Cannot be determined from the information given.

Question 43

What are the predicted phenotypes of the children from a union of a woman who is heterozygous for hemophilia and a man who is normal? (Use the Punnett square to verify your answer.)

A) 100% normal
B) 75% hemophilia: 25 % normal
C) 50% hemophilia: 50% normal
D) 25 % hemophilia: 75% normal
E) 100% hemophilia

Question 44

Gene therapy is:

A) replacing all mutant alleles in body cells.
B) replacing poor copies of alleles with normal alleles.
C) replacing a mutant allele in certain body cells with a normal allele.
D) repairing mutant alleles in certain body cells.
E) improving gene expression in key body cells.

Question 45

Which of the following must be true for a female to inherit hemophilia?

A) Her father has the disease.
B) Her mother is homozygous normal.
C) Her father and mother are heterozygous.
D) Her mother has the disease.
E) Her father is heterozygous.

Question 46

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

Question 47

What factor allows the dominant mutant allele for Huntington's disease to persist in human populations despite its devastating effects?

A) Heterozygote advantage.
B) The fact that its symptoms do not typically show until after the individual has had children.
C) Its effects are not expressed in heterozygous individuals.
D) Its effects are only expressed in homozygous recessive individuals.
E) Its effects are only expressed in homozygous dominant individuals.

Question 48

The current status of gene therapy is:

A) it is currently being used effectively to cure cystic fibrosis.
B) it has been terminated because clinical trials have shown that it is ineffective.
C) it is being evaluated to assess the risks associated with potential side effects.
D) the number of clinical trials is increasing at an almost uncontrolled rate.
E) that it may be considered in the future, but currently the technology is not available.

Question 49

Preimplantation genetic diagnosis is done:

A) after in vitro fertilization on cells from the embryo.
B) in the womb, before birth.
C) after a woman is pregnant, but before the embryo implants.
D) with the help of ultrasound.
E) before fertilization on the sperm and the egg.

Question 50

What is genetic counseling? Briefly explain the role of a genetic counselor.

Question 51

A genetic counselor would know that the probability of having a child affected with a condition inherited as an autosomal recessive would be:

A) 0.5 or 50% if both parents were homozygous normal.
B) 0.5 or 50% if both parents were heterozygous.
C) 0.25 or 25% if both parents were homozygous normal.
D) 0.25 or 25% if both parents were heterozygous.
E) 0% if both parents were heterozygous.

Question 52

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

A) homozygous dominant; more
B) homozygous dominant; less
C) homozygous recessive; less
D) heterozygous; more
E) heterozygous; less

Question 53

Which of the following statements about the abnormal mucous production associated with cystic fibrosis is NOT correct?

A) The mucus blocks the action of the cilia that line the bronchi.
B) The mucus promotes the growth of dangerous bacteria in the respiratory system.
C) The mucus is in the respiratory system is abnormally viscous.
D) Abnormal mucous secretions occur throughout the body systems.
E) Abnormal mucous secretions inhibit infections by bacteria.

Question 54

The selective advantage linked to the high frequency of the cystic fibrosis allele in Caucasians is:

A) an increased resistance to falciparum malaria.
B) the prevention of excessive water loss associated with certain types of diarrhea.
C) production of an enzyme to break down cholera toxin.
D) increased mucous secretions for the removal of infectious cells.
E) an increased probability of Salmonella infection.

Question 55

Hemophilia A is an example of __________ disease and is characterized by a lack of blood-clotting factor __________.

A) an X-linked; VIII
B) a sex-linked recessive; V
C) an autosomal dominant; VIII
D) a sex-linked dominant; V
E) an autosomal recessive; VIII

Question 56

Tay-Sachs disease is a(n) __________ disease that results in blindness, mental retardation, and death due to __________.

A) sex-linked; the absence of one of the sex chromosomes
B) autosomal recessive; accumulation of lipids in brain cells
C) X-linked; accumulation of lipase in cells of sweat glands
D) autosomal; the inability to break down amylase in the intestines
E) autosomal dominant; accumulation of mucus in the lungs

Question 57

Genetic screening can be used to identify all of the following except:

A) PKU.
B) Tay-Sachs disease.
C) Huntington's disease.
D) sickle cell anemia.
E) serotonin deficiency

Question 58

A couple in which the woman is homozygous dominant and the man has hemophilia A will produce:

A) carrier daughters and affected sons.
B) affected daughters and affected sons.
C) carrier daughters and normal sons.
D) normal daughters and normal sons.
E) offspring of unknown genotype for this gene.

Question 59

Which statement is true regarding the ethical considerations surrounding human genetics?

A) Genetic discrimination is not a concern in the US with the scant genetic information known now.
B) Genetic discrimination is not possible when all the genetic information and its effects are known.
C) In the current ethical climate genetic privacy is not a significant concern.
D) Consanguineous matings increase the chances of the inheritances of autosomal recessive alleles.
E) Insurance companies have no arguments for wanting genetic information on their policy holders.

Question 60

An advantage of chorionic villus sampling (compared with amniocentesis) is that:

A) chorionic villus sampling detects a much wider range of genetic defects than does amniocentesis.
B) chorionic villus sampling is much less expensive than is amniocentesis.
C) chorionic villus sampling is much less invasive than amniocentesis.
D) chorionic villus sampling is much easier to perform than amniocentesis.
E) chorionic villus sampling can be performed much earlier than can amniocentesis.

Question 61

Genome-wide association scans compare the proteins of individuals with a particular disease to individuals without the disease.
_________________

Question 62

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
abnormality in a blood clotting protein

Question 63

Studying pedigrees enables human geneticists to predict how traits that are determined by phenotype are inherited.
_________________

Question 64

Describe how amniocentesis is used in the prenatal diagnosis of human genetic abnormalities.Then compare and contrast the benefits and risks associated with amniocentesis and chorionic villus sampling.

Question 65

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
defect in the protein that regulates chloride transport across cell membranes

Question 66

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
absence of an enzyme to break down normal membrane lipid

Question 67

Polyploidy may arise from the failure of chromosomes to separate during cell division or by the fertilization of an egg by more than one sperm.
_________________

Question 68

Males with Klinefelter syndrome lack a Barr Body._______

Question 69

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
defect in amino acid metabolism

Question 70

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
hemoglobin molecules stick to each other

Question 71

In reciprocal translocation, two homologous chromosomes exchange segments.
_________________

Question 72

Sickle cell anemia and cystic fibrosis are examples of homozygote advantage.
_________________

Question 73

Chromosome "painting" distinguishes chromosomes by binding a fluorescent-tagged RNA strand complementary to the denatured DNA of a specific chromosome.
_________________

Question 74

What is the role of heterozygote advantage in maintaining high frequencies of mutant alleles in populations?

Question 75

In trisomy 21 no genetic information is missing from these individuals, but an abnormal copy of this chromosome creates a genetic imbalance which causes abnormal physical and mental development.
_________________

Question 76

Nondisjunction of the XY pair during the first meiotic division can produce sperm with 2 X chromosomes and 2 Y chromosomes.
_________________

Question 77

MATCHING
Match the genetic disease with the molecular defect
a.Phenylketonuria
d.Tays Sach Disease
b.Sickle cell anemia
e.Hemophilia A
c.Cystic fibrosis
Compare and contrast the following three terms: polyploidy, aneuploidy, and nondisjunction.Identify and briefly discuss examples of each of these conditions.

Question 78

In fragile X syndrome, the fragile X gene contains the nucleotide triplet CGG that repeats 200-1000 times.