Genetics Ch 8,12, And 15

Question 1

A chromosome without a centromere is ________.
Question 1 Answer

a.
paracentric

b.
pericentric

c.
acentric

d.
dicentric

e.
segmental

Answer 1

acentric

Question 2

Assume that an organism has a diploid chromosome number of 14. There would be ________ chromosomes in a tetraploid.
Question 2 Answer

a.
14

b.
28

c.
42

d.
56

e.
104

Answer 2

28

Question 3

What error of meiosis leads to both a duplication and a deletion?
Question 3 Answer

a.
replication errors

b.
X-ray chromosomal breakage

c.
unequal crossing over

d.
D loop formation

e.
replication cross formation

Answer 3

unequal crossing over

Question 4

What explanation is generally given for lethality of monosomic individuals?
Question 4 Answer

a.
Monosomy may unmask recessive lethals that are tolerated in heterozygotes carrying the wild-type allele.

b.
The gametes of monosomic individuals cannot undergo meiosis, and this is lethal.

c.
Cells count the number of chromosomes they have and will undergo apoptosis when the chromosome number is incorrect.

d.
Monosomic chromosomes cannot undergo mitosis correctly.

e.
The loss of a single chromosome is not generally lethal, unless the individual is inbred.

Answer 4

Monosomy may unmask recessive lethals that are tolerated in heterozygotes carrying the wild-type allele.

Question 5

Name the polyploid condition that is formed from the addition of an extra set of chromosomes identical to the normal diploid complement of the same species.
Question 5 Answer

a.
autotetraploidy, assuming the normal chromosome complement is haploid

b.
autotetraploidy, assuming the normal chromosome complement is diploid

c.
allotetraploidy, assuming the normal chromosome complement is diploid

d.
alloeuploidy, assuming the normal chromosome complement is diploid

e.
autooctoploidyploidy, assuming the normal chromosome complement is haploid

Answer 5

autotetraploidy, assuming the normal chromosome complement is diploid

Question 6

Having a complete set or sets of chromosomes is called ________.
Question 6 Answer

a.
euploid

b.
monoploid

c.
ploidy

d.
diploid

e.
aneuploidy

Answer 6

euploid

Question 7

An expected meiotic pairing configuration in a ________ would be trivalent.
Question 7 Answer

a.
monoploid

b.
trisomic individual

c.
monosomic individual

d.
diploid

e.
triploid

Answer 7

triploid

Question 8

What is the outcome of nondisjunction in meiosis I?
Question 8 Answer

a.
a resultant gamete that is triploid

b.
a resultant gamete that may harbor from one chromosome both homologs from one parent or none at all

c.
a resultant gamete that may harbor from one chromosome both sister chromatids or none at all

d.
a resultant gamete that is devoid of all chromosomes

e.
four gametes that are all trisomic.

Answer 8

a resultant gamete that may harbor from one chromosome both sister chromatids or none at all

Question 9

Doubling the chromosomes of a sterile species hybrid with colchicine or cold shock is a method used to produce a fertile species hybrid called a ________.
Question 9 Answer

a.
allopolyploid

b.
autoploid

c.
amphidiploid

d.
triploid

e.
autoallopolyploid

Answer 9

amphidiploid

Question 10

Assume that a species has a diploid chromosome number of 24. The term applied to an individual with 25 chromosomes would be ________.
Question 10 Answer

a.
aneuploidy

b.
euploid

c.
triploid

d.
trisomy

e.
aneuploidy and trisomy

Answer 10

aneuploidy and trisomy

Question 11

The condition known as cri-du-chat syndrome in humans has a genetic constitution designated as ________.
Question 11 Answer

a.
45, X

b.
heteroplasmy

c.
46, 5p-

d.
triploidy

e.
trisomy

Answer 11

46, 5p-

Question 12

________ is viewed as a major cause of aneuploidy.
Question 12 Answer

a.
Colchicine treatment

b.
Segmental deletions

c.
Heat treatment

d.
Nondisjunction

e.
X-ray mutations

Answer 12

Nondisjunction

Question 13

Given that a human normally contains 46 chromosomes, give the chromosome number for each of the following conditions: Turner syndrome (female, no Barr bodies), Klinefelter syndrome (male, one Barr body).
Question 13 Answer

a.
47, 47

b.
46, 47

c.
45, 47

d.
45, 46

e.
47, 45

Answer 13

45, 47

Question 14

Which of the following is an example of an endopolyploid?
Question 14 Answer

a.
two diploid mate and produce a tetraploid

b.
an egg has complete nondisjunction and the resultant offspring is triploid

c.
one chromosome is lost during cell division

d.
cells lining the gut of mosquito larvae attain 16n ploidy

e.
an individual suffers from a trisomy

Answer 14

cells lining the gut of mosquito larvae attain 16n ploidy

Question 15

An ________ may arise when three sperm cells are involved in fertilization of a single egg.
Question 15 Answer

a.
autotetraploid

b.
autotriploid

c.
allotriploid

d.
allotetraploid

e.
aneuploidy

Answer 15

autotetraploid

Question 16

A ________ is one whose breakpoints do not flank the centromere.
Question 16 Answer

a.
acentric

b.
segmental

c.
pericentric

d.
dicentric

e.
paracentric

Answer 16

paracentric

Question 17

The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as ________.
Question 17 Answer

a.
polyploidy

b.
euploidy

c.
aneuploidy

d.
triploidy

e.
trisomy

Answer 17

aneuploidy

Question 18

Noninvasive prenatal genetic diagnosis is sometimes preferred to amniocentesis because _______
Question 18 Answer

a.
it gives quicker results

b.
it gives more precise results

c.
it requires only a blood draw from the mother

d.
it requires less technical time of a research lab

e.
the mother does not have to be present

Answer 18

it requires only a blood draw from the mother

Question 19

A child is born with Turner’s syndrome and she is red green color blind (recessive X-linked). Her father is red green color blind as well and her mother is homozygous dominant for color sight. What had to happen in order for this child to be born with this chromosomal complement?
Question 19 Answer

a.
nondisjunction in meiosis I of the father

b.
nondisjunction in meiosis II of the father

c.
nondisjunction in either meiosis I or meiosis II of the mother

d.
nondisjunction in either meiosis I or meiosis II of the father

e.
nondisjunction in meiosis II of the mother

Answer 19

nondisjunction in either meiosis I or meiosis II of the mother

Question 20

Haploinsufficiency refers to ________.
Question 20 Answer

a.
the condition whereby a single cell is insufficient to divide to cause cancer

b.
a state of being whereby a single gene is sufficient to cause several phenotypes

c.
the condition whereby a single chromosome is insufficient to sustain life

d.
the process by which a single gene will cause a cascading effect on a genome’s phenotype

e.
the genetic predisposition for some genes to come in only one copy in the genome

Answer 20

the condition whereby a single chromosome is insufficient to sustain life

Question 21

What is formed when meiosis occurs in an individual who is heterozygous for an intercalary deletion?
Question 21 Answer

a.
a translocation

b.
a compensation loop

c.
a terminal loop

d.
a trifecta chromosomal cross

e.
a translocation cross

Answer 21

a compensation loop

Question 22

Colchicine is an alkaloid derived from plants. What is its effect on chromosome behavior?
Question 22 Answer

a.
By interfering with spindle formation, replicated chromosomes fail to migrate to the poles at anaphase; thus, sister chromatids end up in the same nucleus.

b.
By interfering with spindle formation, replicated chromosomes fail to migrate to the poles at anaphase; thus, homologous chromosomes end up in the same nucleus.

c.
By blocking DNA replication, chromosomes fail to migrate to the poles at anaphase; thus, homologous chromosomes end up in the same nucleus.

d.
By blocking DNA replication, chromosomes do not undergo meiosis I and instead all gametes suffer from aneuploidy.

e.
By blocking DNA replication, chromosomes do not undergo meiosis II and instead half the gametes are empty.

Answer 22

By interfering with spindle formation, replicated chromosomes fail to migrate to the poles at anaphase; thus, sister chromatids end up in the same nucleus.

Question 23

What is the leading cause of Down syndrome?
Question 23 Answer

a.
In older females, chromosome 21 is duplicated leading to abnormal egg formation.

b.
In older parents, there is egg/sperm incompatibility leading to duplication of chromosome 21.

c.
Aberrant implantation in the uterus leads to developmental problems in the fetus.

d.
The nondisjunctional event that produces Down syndrome occurs more frequently during oogenesis in women older than age 35.

e.
In men over 25, sperm formation is impaired and produces monosomic children.

Answer 23

The nondisjunctional event that produces Down syndrome occurs more frequently during oogenesis in women older than age 35.

Question 24

Assume that a species has a diploid chromosome number of 24. The term applied to an individual with 36 chromosomes would be ________.
Question 24 Answer

a.
triploid

b.
monoploid

c.
allopolyploid

d.
aneuploidy

e.
tetraploid

Answer 24

triploid

Question 25

A son is born with Kleinfelter's syndrome and hemophilia. His father was normal and his mother was a carrier for the recessive X-linked blood clotting disorder. What occurred in meiosis to produce this genetic outcome? Question 25 Answer a. nondisjunction in meiosis I of the father b. nondisjunction in meiosis II of the father c. nondisjunction in either meiosis I or meiosis II of the mother d. nondisjunction in meiosis I of the mother e. nondisjunction in meiosis II of the mother

Answer 25

nondisjunction in meiosis II of the mother

Question 26

Name two methods used in genetic prenatal diagnostic testing in humans. Question 26 Answer a. amniocentesis and DSCR b. whole genome sequencing and PCR c. chorionic villus sampling and cellular mitotic analysis d. amniocentesis and NIPGD e. amniocentesis and fetal uterine physiology compatibility test

Answer 26

amniocentesis and NIPGD

Question 27

Trisomy 21, or Down syndrome, occurs when there is a normal diploid chromosomal complement but one (extra) chromosome 21. Although fertility is reduced in both sexes, females have higher fertility rates than males. Van Dyke et al. (1995; Down Syndrome Research and Practice 3(2): 65—69) summarize data involving children born of Down syndrome individuals. Assume that children are born to a female with Down syndrome and a normal 46-chromosome male. What proportion of the offspring would be expected to have Down syndrome? Question 27 Answer a. One-third of the offspring would be expected to have Down syndrome. b. Two-thirds of the offspring would be expected to have Down syndrome. c. All the children would be expected to have Down syndrome. d. None of the offspring would be expected to have Down syndrome. e. One-half of the offspring would be expected to have Down syndrome.

Answer 27

One-half of the offspring would be expected to have Down syndrome.

Question 28

Given that a human normally contains 46 chromosomes, give the chromosome number for each of the following conditions: Triploid, Trisomy 13. Question 28 Answer a. 69, 47 b. 69, 45 c. 138, 47 d. 138, 45 e. 96, 47

Answer 28

69, 47

Question 29

Provide an example of gene redundancy that occurs in both eukaryotes and prokaryotes. Question 29 Answer a. rDNA b. CNV c. centromeres d. spindle fiber protein genes e. cell wall proteins

Answer 29

rDNA

Question 30

What is NOT a potential consequence of a copy number variation? Question 30 Answer a. none b. higher protein levels of specific genes c. phenotypic consequences leading to enhanced ability to fight infection d. loss of function at multiple loci e. phenotypic consequences that track with the number of each gene

Answer 30

loss of function at multiple loci

Question 31

An individual with Patau syndrome would be ________. Question 31 Answer a. termed a triploid b. said to have a monosomy c. said to have a trisomy d. termed a euploid e. termed a haploid

Answer 31

said to have a trisomy

Question 32

What is the relationship among DNA, a gene, and a chromosome? Question 1 Answer a. A gene is composed of DNA, but there is no relationship to a chromosome. b. A gene contains hundreds of chromosomes, which are composed of protein. c. A chromosome contains hundreds of genes, which are composed of DNA. d. A chromosome contains hundreds of genes, which are composed of protein. e. A gene contains hundreds of chromosomes, which are composed of DNA.

Answer 32

A chromosome contains hundreds of genes, which are composed of DNA.

Question 33

The condensed areas in polytene and Lampbrush chromosomes are referred to as ________. Question 2 Answer a. chromomeres b. puffs c. chromatids d. centromeres e. chiasmata

Answer 33

chromomeres

Question 34

If relaxed circular DNA is designated (R), supercoiled circular DNA is designated (S), and linear DNA is designated (L), arrange these conformations in order of increasing rate of sedimentation during centrifugation. Question 3 Answer a. (R), (S), (L) b. (L), (R), (S) c. (L), (S), (R) d. (S), (L), (R) e. (S), (R), (L)

Answer 34

(L), (R), (S)

Question 35

Chromatin of eukaryotes is organized into repeating interactions with protein octamers called nucleosomes. Nucleosomes are composed of which class of molecules? Question 4 Answer a. lipids b. nonhistone chromosomal proteins c. glycoproteins d. H1 histones e. histones

Answer 35

histones

Question 36

In which of the following ways do polytene chromosomes differ from other chromosomes? Question 6 Answer a. Polytene chromosomes represent uncoiled versions of meiotic chromosomes. b. Polytene chromosomes are multiple copies of identical single-stranded DNA. c. Polytene chromosomes can only be found in bacteria. d. Polytene chromosomes are separated but not replicated. e. Polytene chromosomes are replicated but not separated.

Answer 36

Polytene chromosomes are replicated but not separated.

Question 37

The twisted ladder shape of DNA is called a: Question 7 Answer a. hydrogen twist b. double helix c. double membrane d. deoxyribose flip

Answer 37

double helix

Question 38

Which of the following takes the genetic code to the cytoplasm: Question 8 Answer a. DNA b. tRNA c. mRNA d. Deoxyribose

Answer 38

mRNA

Question 39

The hydrolysis of DNA results in _____. Question 9 Answer a. amino acids b. monosaccharides c. nucleotides d. fatty acids

Answer 39

nucleotides

Question 40

Eukaryotic chromosomes contain two general domains that relate to the degree of condensation. These two regions are ________. Question 10 Answer a. each void of typical protein-coding sequences of DNA b. separated by large stretches of repetitive DNA. c. uniform in the genetic information they contain. d. void of introns e. called heterochromatin and euchromatin.

Answer 40

called heterochromatin and euchromatin.

Question 41

This figure represents supercoiled, circular, double-stranded DNA: If this molecule of DNA originated as a linear molecule with a linking number (L) of 30, which was then circularized and unwound, the L for the unwound circular molecule would be ________. Question 11 Answer a. 28 b. 32 c. 30 d. 20 e. 18

Answer 41

28

Question 42

The condition that some organisms contain much larger amounts of DNA than are apparently "needed" and that some relatively closely related organisms may have vastly different amounts of DNA is more typical in ________. Question 12 Answer a. viruses than in bacteria b. RNA viruses than in DNA viruses c. eukaryotes than in prokaryotes d. the alphoid rather than the diploid family e. prokaryotes than in eukaryotes

Answer 42

eukaryotes than in prokaryotes

Question 43

Which statement about Lampbrush chromosomes is incorrect? Question 13 Answer a. They are meiotic chromosomes. b. Instead of being condensed, they are extended. c. Looped out regions are active in RNA synthesis. d. More DNA is looped out from the axis than is required for a single gene. e. The loops consist of two DNA helices, whereas the axis consists of a single DNA helix.

Answer 43

The loops consist of two DNA helices, whereas the axis consists of a single DNA helix.

Question 44

Viral chromosomes exist in a variety of conformations and can be made up of ________. Question 14 Answer a. protein- or lipid-coding sequences b. DNA or RNA c. DNA only d. DNA, RNA, or protein e. RNA only

Answer 44

DNA or RNA

Question 45

In addition to highly repetitive and unique DNA sequences, a third category of DNA sequences exists. What is it called, and what types of elements are involved in it? Question 17 Answer a. composite DNA; telomeres and heterochromatin b. dominant DNA; euchromatin and heterochromatin c. multiple gene family DNA; hemoglobin and 5.0S RNA d. moderately repetitive DNA; SINEs, LINEs, and VNTRs e. permissive DNA; centromeres and heterochromatin

Answer 45

moderately repetitive DNA; SINEs, LINEs, and VNTRs

Question 46

Chromosomes contain _____. Question 18 Answer a. Lipids b. DNA c. both Proteins and DNA d. Carbohydrates e. proteins

Answer 46

both Proteins and DNA

Question 47

In E. coli, the genetic material is composed of ________. Question 19 Answer a. circular, double-stranded DNA b. linear, double-stranded DNA c. RNA and protein d. circular, double-stranded RNA e. polypeptide chains

Answer 47

circular, double-stranded DNA

Question 48

Tautomeric shifts ________. Question 1 Answer a. are likely to cause frameshifts b. allow purines to bind to purines c. are known to cause insertion or deletion mutations d. can cause missense mutations due to mispairings e. allow pyrimidines to bind to pyrimidines

Answer 48

can cause missense mutations due to mispairings

Question 49

A mutation that changes an amino acid-coding codon to a stop codon is classified as what kind of codon? Question 2 Answer a. missense b. silent c. nonsense d. conditional e. neutral

Answer 49

nonsense

Question 50

Transposons, or jumping genes, are DNA elements that move within the genome. In which organismic groups are transposons found? Question 3 Answer a. ancient bacteria b. all organismic groups c. bacteria d. eukaryotes e. mammals

Answer 50

all organismic groups

Question 51

One would predict that bacteria that lack the enzyme photolyase would be more sensitive to what kind of mutagen? Question 4 Answer a. reactive oxygen species b. base analog c. intercalating agents d. UV light e. alkylating agents

Answer 51

UV light

Question 52

Adenine methylase is an enzyme used during mismatch repair (MMR). It helps determine which strand needs to be repaired by discriminating between template and new DNA strand. If this enzyme is mutated, how would MMR be affected? Question 5 Answer a. MMR would not be hindered because adenine methylase is not directly involved in MMR. b. MMR would be hindered because both strands would be overmethylated and both would appear as new DNA strands and it would not be able to determine which strand has the error. c. MMR would be hindered because both strands would be unmethylated and both would appear as new DNA strands and it would not be able to determine which strand has the error. d. MMR would be hindered because both strands would be unmethylated and both would appear as template DNA strands. e. MMR would be hindered because both strands would be overmethylated and both would appear as template DNA strands and it would not be possible to determine which strand has the mutation.

Answer 52

MMR would be hindered because both strands would be unmethylated and both would appear as new DNA strands and it would not be able to determine which strand has the error.

Question 53

Mutations that arise in nature, from no particular artificial agent, are called ________. Question 6 Answer a. cosmic mutations b. nutritional mutations c. spontaneous mutations d. induced mutations e. chromosomal losses

Answer 53

spontaneous mutations

Question 54

Which of the following mutagens is matched correctly with its action? Question 7 Answer a. 5-Bromouracil is an alkylating agent b. acetaldehyde is a free radicle c. ethidium bromide is an intercalating agent d. mustard gasses are base analogs e. 2-Amino purine is an adduct-forming agent

Answer 54

ethidium bromide is an intercalating agent

Question 55

Which of the following diseases are caused by an expansion of trinucleotide repeats? Question 8 Answer a. achondroplasia b. beta-thalassemia c. cystic fibrosis d. fragile X syndrome e. Marfan's syndrome

Answer 55

fragile X syndrome

Question 56

Barbara McClintock discovered mobile elements in corn by analyzing the genetic behavior of two elements, Ds and Ac. The interplay between these two elements has become one of the most interesting stories of discovery in the field of genetics. How do Ds and Ac interact? Question 9 Answer a. Both elements can move only within chromosome 9. b. The movement of Ac is dependent on two forms of Ds. c. Ac causes a deletion next to the insertion site of Ds. d. While Ds moves only if Ac is present in the genome, Ac is capable of autonomous movement. e. Ds causes a deletion next to the insertion site of Ac.

Answer 56

While Ds moves only if Ac is present in the genome, Ac is capable of autonomous movement.

Question 57

Germ cell mutations ________. Question 10 Answer a. are of no consequence to the next generation b. affect somatic cell function in the current generation c. are the cause of testicular cancer d. are usually found in every cell of the next generation e. are only seen in females

Answer 57

are usually found in every cell of the next generation

Question 58

During the Ames test, his− bacteria are exposed to a chemical. If the bacteria remains his+, then what can we say about the chemical? Question 11 Answer a. The chemical is safe to consume even though it is likely a mutagen. b. The chemical is safe to consume and is not likely a mutagen. c. The chemical is certainly a cancer-causing chemical. d. The chemical is not safe to consume even though it is not likely a mutagen. e. The chemical is not safe to consume because it is likely a mutagen.

Answer 58

The chemical is not safe to consume because it is likely a mutagen.

Question 59

Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are genetically incapable of repairing some dimers at "normal" rates. Such individuals are likely to suffer from ________. Question 12 Answer a. SCID b. phenylketonuria c. xeroderma pigmentosum d. Huntington disease e. muscular dystrophy

Answer 59

xeroderma pigmentosum

Question 60

At what stage is a mutation predicted to have the effect? Question 13 Answer a. during early embryonic development b. shortly after birth c. after the age of 60 d. after puberty e. after birth but before puberty

Answer 60

during early embryonic development

Question 61

Which of the following two mutagens that would be classified as base analogs? Question 14 Answer a. hydroxyurea and peroxidase b. acridine orange and proflavine c. ethylmethane sulfonate and ethylmethylketone peroxide d. ultraviolet light and cosmic radiation e. 5-Bromouracil and 2-amino purine

Answer 61

5-Bromouracil and 2-amino purine

Question 62

Which repair mechanism is most likely affected if the enzyme DNA glycosylase is not functioning properly? Question 15 Answer a. nucleotide excision repair b. SOS repair c. base excision repair d. photoreactivation repair e. double-strand break repair

Answer 62

base excision repair

Question 63

In bacteria and eukaryotes, a mutation is when ________. Question 16 Answer a. the nucleotide sequence in an mRNA molecule is directly changed b. the expression of a gene changes without the DNA sequence being changed c. DNA is unable to be replicated d. the nucleotide sequence in a DNA molecule is directly changed e. the amino acid sequence in a protein molecule is directly changed

Answer 63

the nucleotide sequence in a DNA molecule is directly changed

Question 64

A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to be which of the following? Question 17 Answer a. frameshift b. base analog c. transversion d. transition e. recombinant

Answer 64

frameshift

Question 65

Some bacterial transposons, known as Tn elements, are larger than insertion sequences (IS elements) and contain protein-coding genes that have human health significance. What might such a bacterial transposon contain? Question 18 Answer a. dissociation element b. proto-oncogene c. pseudogene d. drug resistance e. oncogene

Answer 65

drug resistance

Question 66

Which of the following mutations would be classified as a transversion? Please choose all that apply. Question 19 Answer a. CGA to a CGT b. CGA to a CCA c. CGA to GCT d. CGA to a GGA e. CGA to a CGU

Answer 66

CGA to a CGT

Question 67

From the Luria-Delbruck fluctuation test, when would mutations arise in yeast cells to allow for survival in the presence of toxic levels of hydrogen peroxide? Question 20 Answer a. Mutations are adaptive and would have appeared after most of the cells died in the presence of hydrogen peroxide. b. Mutations are random and would have appeared prior to being exposed to hydrogen peroxide. c. Mutations are adaptive and would have appeared immediately in response to the hydrogen peroxide. d. Mutations are random but would not have formed until after the hydrogen peroxide was introduced. e. Mutations are adaptive and would have formed prior to being exposed to hydrogen peroxide.

Answer 67

Mutations are random and would have appeared prior to being exposed to hydrogen peroxide.

Question 68

All insertion sequences (IS elements) contain two structural elements that are essential for their movement. What are these two elements? Question 21 Answer a. integrase and oncogenes b. transposase and inverted terminal repeats c. proto-oncogenes and oncogenes d. integrase and pseudogenes e. transposase and oncogenes

Answer 68

transposase and inverted terminal repeats

Question 69

Thymine dimers form when ________. Question 22 Answer a. two thymines are inserted into a DNA sequence b. two thymines on separate strands of DNA bind to together c. two thymines on the same strand and adjacent to each other bind together d. two thymines adjacent to each other are deleted from the DNA sequence e. two thymines on the same strand but not adjacent to each other bind together

Answer 69

two thymines on the same strand and adjacent to each other bind together