Chapter 19 Human Genetics Verified Test Bank

Student name:__________

TRUE/FALSE - Write 'T' if the statement is true and 'F' if the statement is false.
1) A mature red blood cell is useful for karyotyping.

⊚ true
⊚ false

2) Test results from amniocentesis are immediate.

⊚ true
⊚ false

3) Nondisjunction can only occur with autosomes, not the sex chromosomes.

⊚ true
⊚ false

4) Most nondisjunction embryos fail to survive.

⊚ true
⊚ false

5) The incidence of Down syndrome is ten times higher when the mother is over forty years old compared to when the mother is under that age.

⊚ true
⊚ false

6) Dominant alleles code for beneficial traits.

⊚ true
⊚ false

7) A genetic disorder can lead to the synthesis of an abnormal protein.

⊚ true
⊚ false

8) The order of 99.9% of the base pairs of all people is exactly the same.

⊚ true
⊚ false

9) Over 50% of the genome codes for proteins.

⊚ true
⊚ false

10) Each individual's DNA contains over one million genes.

⊚ true
⊚ false

MULTIPLE CHOICE - Choose the one alternative that best completes the statement or answers the question.
11) An autosome is

A) an X chromosome.
B) a Y chromosome.
C) a chromosome that is not a sex chromosome.
D) any chromosome that is in a gamete.

12) A human female body cell contains

A) 46 chromosomes.
B) 44 autosomes.
C) 2 X chromosomes.
D) All apply.

13) A display of an individual's chromosomes arranged by size, shape, and banding patterns is its

A) somatotype.
B) karyotype.
C) syndrome.
D) chromotype.
E) proteome.

14) In adults, the cell used most often for karyotyping is a

A) red blood cell.
B) skin cell.
C) gamete.
D) white blood cell.

15) What procedure is used to obtain embryonic or fetal chromosomes for karyotyping?

A) Chorionic villi sampling (CVS)
B) Ultrasonography
C) Amniocentesis
D) Both chorionic villi sampling (CVS) and amniocentesis are used

16) Which procedure can be performed earlier in pregnancy but involves a higher risk of spontaneous abortion?

A) Chorionic villi sampling (CVS)
B) Amniocentesis

17) A polar body biopsy is a type of

A) chorionic villi sampling (CVS) in which villi of the polar body are tested.
B) amniocentesis in which polar bodies are sampled from fluids surrounding the fetus.
C) gene therapy in which a polar body is inserted into a zygote.
D) preimplantation genetic study in which a polar body is tested for genetic disorders.

18) Blood tests done with pregnant women routinely test for all of the following chemicals EXCEPT

A) vitamin C.
B) human chorionic gonadotropin.
C) estriol.
D) alpha-fetoprotein.

19) In preparing a cell sample for karyotyping, when are the cells most visible?

A) Prophase
B) Metaphase
C) Anaphase
D) Telophase

20) How early can chorionic villi sampling be done?

A) Second week of pregnancy
B) Fifth week of pregnancy
C) Eighth week of pregnancy
D) Tenth week of pregnancy

21) When does nondisjunction occur?

A) Anaphase of mitosis
B) Telophase of mitosis
C) Anaphase of meiosis I or II
D) Metaphase of meiosis II

22) Trisomy could result from

A) an ovum of 24 chromosomes fertilized by a sperm with 23 chromosomes.
B) an ovum of 22 chromosomes fertilized by a sperm with 23 chromosomes.
C) an ovum of 23 chromosomes fertilized by a sperm with 23 chromosomes.
D) None apply.

23) Monosomy could result from

A) an ovum of 24 chromosomes fertilized by a sperm with 23 chromosomes.
B) an ovum of 22 chromosomes fertilized by a sperm with 23 chromosomes.
C) an ovum of 23 chromosomes fertilized by a sperm with 23 chromosomes.
D) None apply.

24) Which condition occurs as a result of nondisjunction?

A) Down syndrome
B) Turner syndrome
C) Poly-X syndrome
D) All apply.

25) Down syndrome is due to an extra

A) X chromosome.
B) Y chromosome.
C) autosome.
D) X chromosome or an extra Y chromosome.

26) Another name for Down syndrome is

A) trisomy 23.
B) monosomy 15.
C) trisomy 21.
D) monosomy 20.

27) The sex of a child is determined by the

A) sperm.
B) egg.
C) either sperm or egg.

28) Research indicates that it is most commonly the _____ that contributes the extra chromosome to the zygote in cases of trisomy 21.

A) ovum
B) sperm

29) Turner syndrome is due to a(an)

A) extra sex chromosome.
B) missing sex chromosome.
C) extra autosome.
D) missing autosome.

30) An XO individual will have

A) Klinefelter syndrome.
B) Jacobs syndrome.
C) Turner syndrome.
D) Poly-X syndrome.

31) An individual with Turner syndrome is a

A) female with nonfunctional ovaries and uterus.
B) female with functional ovaries and uterus.
C) male with nonfunctional testes.
D) male with functional testes.

32) An individual with one Y and two or more X chromosomes has

A) Klinefelter syndrome.
B) Jacobs syndrome.
C) Turner syndrome.
D) Poly-X syndrome.

33) An individual with Klinefelter syndrome would be a

A) female with underdeveloped ovaries and uterus.
B) female with fully functional ovaries and uterus.
C) male with underdeveloped testes.
D) male with fully functional testes.

34) Poly-X females are

A) never fertile.
B) hermaphrodites.
C) normally fertile.
D) nonexistent.

35) YO individuals are

A) feminized males.
B) masculine females.
C) nonexistent.
D) normal males.

36) XYY individuals are usually

A) feminized males.
B) sterile females.
C) males with speech and reading problems.
D) nonexistent.

37) An individual with XYY has

A) Klinefelter syndrome.
B) Jacobs syndrome.
C) Turner syndrome.
D) Poly-X syndrome.

38) The nondisjunction event that leads to Jacobs syndrome occurs during

A) oogenesis.
B) spermatogenesis.
C) mitosis.
D) blastocyst formation.

39) Which sex chromosome(s) is(are) needed for life?

A) X
B) Y
C) X and Y

40) Genotype refers to

A) an individual's nationality.
B) the physical appearance of an individual.
C) the alleles an individual has.
D) Both the nationality of an individual and the alleles an individual has are correct.

41) Phenotype is

A) the genes of an individual.
B) the physical appearance of an individual.
C) the alleles an individual has.
D) both the physical appearance of an individual and the alleles an individual has are correct.

42) Which genotype is homozygous?

A) DD
B) dd
C) Dd
D) Both DD and dd are correct.

43) A genotype of DD is

A) heterozygous.
B) homozygous recessive.
C) heterozygous recessive.
D) homozygous dominant.

44) A genotype of Bb is

A) heterozygous.
B) homozygous recessive.
C) heterozygous recessive.
D) homozygous dominant.

45) A genotype of tt is

A) homozygous recessive.
B) homozygous dominant.
C) heterozygous.
D) sex-linked.

46) An individual that has a dominant allele will have the phenotype of the

A) dominant trait.
B) recessive trait.
C) neither trait.
D) both traits.

47) Carriers for recessive disorders are

A) homozygous dominant.
B) heterozygous.
C) homozygous recessive.
D) either heterozygous or homozygous recessive.

48) Different forms of a gene are called

A) loci.
B) alleles.
C) homozygous.
D) homologous.

49) A heterozygote has two different

A) loci for the same phenotype.
B) alleles for the same trait.
C) chromatids on the same chromosome.
D) genes made of identical base sequences.
E) traits expressed in different body cells.

50) An X-linked trait inherited by a male comes from his

A) father.
B) mother.
C) father or the mother.
D) both father and the mother.

51) Can a female have an X-linked recessive disorder?

A) Never.
B) Yes, and this occurs frequently.
C) Yes, but this occurs infrequently.
D) Yes, and it is only females who have this type of disorder.

52) Color blindness is more common in men; it is a(n)

A) autosomal dominant disorder.
B) sex-linked co-dominant disorder.
C) X-linked recessive disorder.
D) Y-linked dominant disorder.
E) endocrine-relateddisorder.

53) An abnormal allele, leading to an abnormal channel protein, is the cause of

A) hemophilia.
B) cystic fibrosis.
C) unattached earlobes.
D) asthma.

54) A-B-O blood typing is an example of codominance. Someone with AB blood produces

A) only the A protein.
B) only the B protein.
C) only the O protein.
D) neither the A nor the B protein.
E) both the A and the B protein.

55) Someone with type O blood

A) is homozygous for the recessive allele, which is O.
B) has at least one copy of the dominant allele, which is O.
C) has both the A and B alleles which co-dominateto create type O.
D) does not have any alleles at the blood type locus.

56) What short-cut is used to predict the probability of inheriting a particular trait based on the parents' genotypes?

A) Karyotype
B) Electrophoresis
C) Punnett square
D) Amniocentesis

57) In a case where both parents were carriers of an autosomal recessive disorder, what would be the probability that one of their children would have that disorder?

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

58) In a case where one parenthad an autosomal dominant disorder, and the other did not, what would be the probability that one of their children would have that disorder?

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

59) What is the most lethal genetic disorder among Caucasians in the United States?

A) Down syndrome
B) Tay-Sach's disease
C) Spina bifida
D) Cystic fibrosis

60) In which situation can a child born with a genetic disease have two normal parents?

A) When the disease gene is dominant and the parents are heterozygous
B) When the disease gene is recessive and the parents are heterozygous
C) When the disease gene is either dominant or recessive
D) It is not possible.

61) One way researchers and counselors deduce genetic patterns of a disorder is to construct a diagram of the inheritance of that disorder called a(an)

A) karyotype.
B) pedigree.
C) amniocentesis.
D) preimplantation genetic diagnosis.

62) Which of the following is NOT a dominant inherited disorder?

A) Neurofibromatosis
B) Achondroplasia
C) Hemophilia
D) Huntington disease

63) Which of the following is NOT a recessive inherited disorder?

A) Cystic fibrosis
B) Phenylketonuria
C) Sickle-cell disease
D) Muscular dystrophy

64) Which of the following is NOT a multiple gene inherited disorder?

A) Cleft-lip
B) Spina bifida
C) Tay-Sachs disease
D) Hydrocephalus

65) Which of the following is NOT a sex-linked inherited disorder?

A) Thalassemia
B) Color blindness
C) Hemophilia
D) Muscular dystrophy

66) The insertion of genetic material into human cells for treatment of a disorder is

A) a pedigree.
B) a genome.
C) amniocentesis.
D) gene therapy.

67) The most common vector that is used to transport DNA into a cell for gene therapy is a(an)

A) virus.
B) bacteria.
C) cancer cell.
D) allergen.

68) The most common virus class used as a vector is the

A) retrovirus.
B) herpes virus.
C) adenovirus.
D) liposome.

69) Which of the following are alternate ways to introduce DNA into a cell (other than viruses)?

A) Direct insertion of the gene into the cell
B) Attachment of the gene to a liposome
C) Attachment of the gene to receptors on the cell membrane
D) All apply.

70) All the genetic information in all the chromosomes of an individual is their

A) genome.
B) karyotype.
C) pedigree.
D) All apply.

71) Preimplantation genetic studies are done just before

A) placement of an embryo into the uterus for development.
B) sampling of the chorionic villi to determine fetal health.
C) delivery of the child by cesarean section.