Name: 
 

exam 3 review, july 2004


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 
Who discovered chromosomes?
a.
Morgan
b.
Mendel
c.
Sturtevant
d.
Weismann
e.
Flemming
 

2. 
Who discovered the process of meiosis?
a.
Morgan
b.
Mendel
c.
Sturtevant
d.
Weismann
e.
Flemming
 

3. 
Who was the first to use fruit flies in genetics experiments?
a.
Morgan
b.
Mendel
c.
Sturtevant
d.
Weismann
e.
Flemming
 

4. 
Weismann proposed that
a.
the number of chromosomes is cut in half in the sex cells.
b.
the number of chromosomes is doubled at fertilization
c.
half the chromosomes in a diploid cell come from the father and the other half from the mother.
d.
fertilization restores the number of chromosomes present in each parent.
e.
all of these
 

5. 
Genes are
a.
located on chromosomes.
b.
inherited in the same way as chromosomes.
c.
arranged in linear sequence on chromosomes.
d.
assorted independently during meiosis.
e.
all of these
 

6. 
Chromosomes other than those involved in sex determination are known as
a.
nucleosomes.
b.
heterosomes.
c.
alleles.
d.
autosomes.
e.
liposomes.
 

7. 
DNA coding regions that affect the same trait are called
a.
homologues.
b.
alleles.
c.
autosomes.
d.
loci.
e.
gametes.
 

8. 
The location of a gene on a chromosome is its
a.
centromere.
b.
locus.
c.
autosome.
d.
allele.
e.
none of these
 

9. 
A karyotype
a.
compares one set of chromosomes to another.
b.
is a visual display of chromosomes arranged according to size.
c.
is a photograph of cells undergoing mitosis during anaphase.
d.
of a normal human cell shows 48 chromosomes.
e.
cannot be used to identify individual chromosomes beyond the fact that two chromosomes are homologues.
 

10. 
In karyotyping, individual chromosomes may be distinguished from others by
a.
a comparison of chromosome lengths.
b.
bands produced on chromosomes by differential staining.
c.
the position of centromeres.
d.
all of these
e.
none of these
 

11. 
Karyotyping is usually done using what kind of cells?
a.
muscle
b.
blood
c.
cartilage
d.
sex
e.
epidermal
 

12. 
Which chemical is used to keep chromosomes from separating during metaphase?
a.
Giemsa stain
b.
acetone
c.
colchicine
d.
alcohol
e.
formaldehyde
 

13. 
Karyotyping involves taking pictures of chromosomes during
a.
prophase.
b.
telophase.
c.
metaphase.
d.
interphase.
e.
anaphase.
 

14. 
Karyotype analysis
a.
is a means of detecting and reducing mutagenic agents.
b.
is a surgical technique that separates chromosomes that have failed to segregate properly during meiosis II.
c.
is used to detect chromosomal mutations and metabolic disorders in embryos.
d.
substitutes defective alleles with normal ones.
e.
all of these
 

15. 
Sex chromosomes
a.
determine sex.
b.
vary from one sex to another.
c.
carry some genes that have nothing to do with sex.
d.
were unknown to Mendel.
e.
all of these
 

16. 
Which of the following designates a normal human female?
a.
XXY
b.
XY
c.
XX
d.
XYY
e.
XO
 

17. 
Which of the following designates a normal human male?
a.
YY
b.
XX
c.
XY
d.
XO
e.
XYY
 

18. 
In his experiments with Drosophila melanogaster, Morgan demonstrated that
a.
fertilized eggs have two sets of chromosomes, but eggs and sperms have only one set in each gamete.
b.
aneuploidy exists in karyotypes that have undergone deletions and inversions in specific chromosomes.
c.
colchicine is effective in producing polyploidy in F2 generations.
d.
certain genes are located only on an X chromosome and have no corresponding alleles on the Y chromosome.
e.
all of these
 

19. 
All of the genes located on a given chromosome comprise a
a.
karyotype.
b.
bridging cross.
c.
wild-type allele.
d.
linkage group.
e.
none of these
 

20. 
If two genes are on the same chromosome,
a.
crossing over occurs frequently.
b.
they assort independently.
c.
they are in the same linkage group.
d.
they are segregated during meiosis.
e.
an inversion will usually occur.
 

21. 
If two genes are almost always found in the same gamete, they are
a.
located close together on the same chromosome.
b.
located on nonhomologous chromosomes.
c.
located far apart on the same chromosome.
d.
found on the sex chromosome.
 

22. 
Genes that are located on the same chromosome
a.
tend to be inherited together.
b.
will appear together in the gamete.
c.
are said to be linked.
d.
may be separated during crossing over.
e.
all of these
 

23. 
If alleles L, M, and N are on the maternal chromosome and l, m, and n are on the paternal chromosome, the only way that a gamete from a heterozygote will produce a gamete with alleles l, m, and N is through
a.
nondisjunction.
b.
the laws of segregation.
c.
the law of independent assortment.
d.
crossing over.
e.
chromosome aberration.
 

24. 
If the paternal chromosome has alleles L, M, and n and the maternal chromosomes have l, m, and N, then the chromosome that cannot be produced by crossing over is
a.
LMN
b.
LMn
c.
LmN
d.
Lmn
e.
lmn
 

25. 
Genetic recombination as a result of crossing over occurs more readily in genes that are located
a.
on the sex chromosomes.
b.
on the autosomes.
c.
close together on the same chromosome.
d.
far apart on the same chromosome.
e.
on different chromosomes.
 

26. 
Which is NOT a chromosomal aberration?
a.
deletion
b.
extra chromosomes
c.
translocation (exchange of parts between nonhomologues)
d.
crossing over
e.
inversion
 

27. 
Which of the following would be the least satisfactory organism for genetic research?
a.
humans
b.
bacteria
c.
corn
d.
fruit flies
e.
peas
 

28. 
In a pedigree chart a male showing the specific trait being studied is indicated by a
a.
darkened square.
b.
clear square.
c.
darkened diamond.
d.
clear triangle.
e.
darkened circle.
 

29. 
In a pedigree chart a female who does not demonstrate the trait being studied is represented by a
a.
darkened square.
b.
clear diamond.
c.
clear circle.
d.
darkened triangle.
e.
darkened oval.
 

30. 
All of the following would be classified as genetic disorders except
a.
galactosemia
b.
polydactyly.
c.
progeria.
d.
hemophilia.
e.
Turner syndrome.
 

31. 
Galactosemia
a.
is an X-linked recessive trait expressed more commonly in males.
b.
occurs more frequently in some ethnic groups than others.
c.
is an autosomal recessive inheritance.
d.
must be homozygous to be expressed.
e.
is an autosomal recessive inheritance and must be homozygous to be expressed.
 

32. 
A colorblind man and a woman with normal vision whose father was colorblind have a son. Colorblindness, in this case, is caused by an X-linked recessive gene. If only the male offspring are considered, the probability that their son is colorblind is
a.
.25 (or 25 percent).
b.
.50 (or 50 percent).
c.
.75 (or 75 percent).
d.
1.00 (or 100 percent).
 

33. 
Red-green colorblindness is an X-linked recessive trait in humans. A colorblind woman and a man with normal vision have a son. What is the probability that the son is colorblind?
a.
100 percent
b.
75 percent
c.
50 percent
d.
25 percent
e.
0 percent
 

34. 
Red-green colorblindness is an X-linked recessive trait in humans. What is the probability that a colorblind woman and a man with normal vision will have a colorblind daughter?
a.
100 percent
b.
75 percent
c.
50 percent
d.
25 percent
e.
0 percent
 

35. 
If a daughter expresses an X-linked recessive gene, she inherited the trait from
a.
her mother.
b.
her father.
c.
both parents.
d.
neither parent.
e.
her grandmother.
 

36. 
A human X-linked recessive gene may be
a.
found on the Y chromosome.
b.
passed to daughters from their fathers.
c.
passed to sons from their mothers.
d.
expressed more commonly among females.
e.
passed to daughters from their fathers and to sons from their mothers.
 

37. 
An X-linked carrier is a
a.
homozygous dominant female.
b.
heterozygous female.
c.
homozygous recessive female.
d.
homozygous male.
e.
heterozygous male.
 

38. 
A human X-linked gene is
a.
found only in males.
b.
more frequently expressed in females.
c.
found on the Y chromosome.
d.
transmitted from father to son.
e.
found on the X chromosome.
 

39. 
Colorblindness is an X-linked trait in humans. If a colorblind woman marries a man with normal vision,
a.
only their daughters will be colorblind.
b.
their sons will be colorblind; daughters will be carriers.
c.
their sons will have normal vision; their daughters will be carriers.
d.
all their children will be colorblind.
e.
all their children will have normal vision.
 

40. 
A woman heterozygous for colorblindness (an X-linked recessive allele) marries a man with normal color vision. What is the probability that their first child will be colorblind?
a.
25 percent
b.
50 percent
c.
75 percent
d.
100 percent
e.
none of these
 

41. 
Queen Victoria
a.
was a carrier of hemophilia.
b.
had a hemophilic parent.
c.
had hemophilia.
d.
married a man with hemophilia.
e.
both had a hemophilic parent and married a man with hemophilia.
 

42. 
Hemophilia
a.
is rare in the human population.
b.
is more common among men.
c.
was common in English royalty.
d.
is an X-linked recessive trait.
e.
all of these
 

43. 
A chromosome's gene sequence that was ABCDEFG before modification and ABCDLMNOP afterward is an example of
a.
inversion.
b.
deletion.
c.
duplication.
d.
translocation.
e.
crossing over.
 

44. 
A chromosome's gene sequence that was ABCDEFG before modification and ABCDCDEFG afterward is an example of
a.
inversion.
b.
deletion.
c.
duplication.
d.
translocation.
e.
crossing over.
 

45. 
A chromosome that has been broken and rejoined in a reversal sequence has undergone
a.
inversion.
b.
deletion.
c.
duplication.
d.
translocation.
e.
crossing over.
 

46. 
A chromosome's gene sequence that was ABCDEFG before damage and ABCFG after is an example of
a.
inversion.
b.
deletion.
c.
duplication.
d.
translocation.
e.
crossing over.
 

47. 
A chromosome's gene sequence that was ABCDEFG before damage and ABFEDCG after is an example of
a.
inversion.
b.
deletion.
c.
duplication.
d.
translocation.
e.
crossing over.
 

48. 
Certain human cancer cells may demonstrate which of the following?
a.
deletion
b.
inversion
c.
translocation
d.
duplication
e.
none of these
 

49. 
The condition occurring when an organism has a 2n + 1 chromosome composition is known as
a.
monosomy.
b.
trisomy.
c.
diploid.
d.
haploid.
e.
both trisomy and haploid.
 

50. 
Down syndrome involves trisomy
a.
3.
b.
5.
c.
15.
d.
19.
e.
21.
 

51. 
Syndrome means
a.
a chromosome disorder.
b.
a simple genetic disease.
c.
a set of symptoms that occur together.
d.
an incurable disease.
e.
a rare inborn defect.
 

52. 
In Down syndrome
a.
as the age of the mother increases, the chance of the defect occurring in the unborn children increases.
b.
the father has very little influence on the defect.
c.
most embryos abort before complete term.
d.
a person with the defect cannot have a normal child.
e.
none of these
 

53. 
The sex chromosome composition of a person with Turner syndrome is
a.
XXX.
b.
XO.
c.
XXY.
d.
XYY.
e.
none of these
 

54. 
The sex chromosome composition of a person with Klinefelter syndrome is
a.
XXX.
b.
XO.
c.
XXY.
d.
XYY.
e.
none of these
 

55. 
Suppose a hemophilic male (X-linked recessive allele) and a female carrier for the hemophilic trait have a nonhemophilic daughter with Turner syndrome. Nondisjunction could have occurred in
a.
both parents.
b.
neither parent.
c.
the father only.
d.
the mother only.
e.
none of these
 

56. 
A genetic abnormality that may result in sterile males with mental retardation or breast enlargement is
a.
XXY.
b.
XYY.
c.
Turner syndrome.
d.
Down syndrome.
e.
none of these
 

57. 
Males who tend to be taller than average and show mild mental retardation may be designated
a.
XXY.
b.
XYY.
c.
Turner syndrome.
d.
Down syndrome.
e.
none of these
 

58. 
Nondisjunction involving the X chromosomes may occur during oogenesis and produce two kinds of eggs. If normal sperm fertilize these two types, which of the following pairs of genotypes are possible?
a.
XX and XY
b.
XXY and XO
c.
XYY and XO
d.
XYY and YO
e.
none of these
 

59. 
Routine treatments for genetic disorders currently involve
a.
substituting normal for defective parents.
b.
substituting normal for defective genes.
c.
supplying a missing gene.
d.
supplying missing enzymes or gene products.
e.
all of these
 

60. 
Phenotypic treatments for genetic disorders include
a.
preventing the disorders in the carriers.
b.
elimination of the defective gene.
c.
preventing a disorder from being passed on.
d.
preventing a disorder from being expressed.
e.
all of these
 

61. 
Phenotypic treatments
a.
may increase the number of defective genes in a population.
b.
do not affect the number of defective genes in a population.
c.
decrease the number of defective genes in a population.
d.
are the ultimate cures for genetic disorder.
e.
have no biological value for either the individual or the population.
 

62. 
Symptoms of phenylketonuria (PKU) may be minimized or suppressed by a diet low in
a.
serine.
b.
glycine.
c.
phenylalanine.
d.
proline.
e.
glutamic acid.
 

63. 
Galactose buildup in galactosemia can be detected by
a.
karyotyping.
b.
urine analysis.
c.
blood tests.
d.
saliva tests.
e.
both urine analysis and blood tests.
 

64. 
Preimplantation diagnosis
a.
usually requires abortion.
b.
relies on in-vitro fertilization.
c.
is a form of amniocentesis.
d.
is a phenotypic treatment.
e.
occurs about midway through a pregnancy.
 

65. 
Amniocentesis involves sampling
a.
the fetus directly.
b.
the fetal cells floating in the amniotic fluid.
c.
sperm.
d.
blood cells.
e.
placental cells.
 

66. 
Amniocentesis is
a.
a surgical means of repairing deformities.
b.
a form of chemotherapy that modifies or inhibits gene expression or the function of gene products.
c.
used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos.
d.
a form of gene replacement therapy.
e.