Deck 24: Chromosomal Basis of Inheritance

Question 1

All of the genes on a single chromosome are

A) A locus
B) Homologous
C) A linkage map
D) A linkage group
E) An allele

Answer 1

D
Explanation: The genes on a single chromosome are often inherited as a group with those closer together more likely to be passed as a unit or a linkage group.Bloom's

Question 2

Which statement is NOT true about Down syndrome?

A) It is caused by a third copy of chromosome 21.
B) Greatly increased incidence occurs with fathers over age 40.
C) It is usually associated with chromosomal nondisjunction in meiosis.
D) Characteristics include mental retardation and extra eyelid folds.
E) Affected individuals display mental retardation.

Answer 2

B
Explanation: Down syndrome or trisomy 21 occurs when nondisjunction of the 21^st chromosome leads to an extra copy of the chromosome and it is frequently seen when older women give birth although the extra chromosome 21 can come from the father as well. There is less evidence that suggests that male's age has an effect on the incidences of nondisjunction in males.Bloom's

Question 3

Color-blindness is inherited as an X-linked recessive trait.A male who is color-blind marries a heterozygous woman.What percent of their total children will be color-blind?

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

Answer 3

C
Explanation: Given that X^B= normal color vision and X^b = color blind (recessive), a heterozygous female would be X^BX^b and a color blind man would be X^bY. Daughters would have a 50% chance of inheriting normal color vision but they will be heterozygous for the trait, the other 50% will be color blind. Sons have the same 50/50 chance of normal versus color blind vision. Notice that this is based on the probability of the X chromosome that they will inherit from their mother since the will not receive an X from their father; for daughter it is still the mother's X chromosome that makes the difference since the X chromosome they would inherit from their father must carry the color blind allele.Bloom's

Question 4

Karyotyping can be used to diagnose which of the following genetic disorders?

A) Down syndrome
B) phenylketonuria
C) neurofibromatosis
D) cystic fibrosis
E) hemophilia

Question 5

A person who has an extra copy of a chromosome is said to have

A) monosomy.
B) bisomy.
C) trisomy.
D) nondisjunction.
E) duplication.

Question 6

What determines whether or not genes located on the same chromosome can assort independently?

A) Genes located on the same chromosome can never assort independently.
B) Genes located on the same chromosome always assort independently.
C) Whether or not independent assortment occurs is just due to random chance.
D) The distance between genes located on the same chromosome determines whether or not they can show any level of independent assortment.
E) The phenotype that the gene will express.

Question 7

Which refers to the loss of a complete chromosome?

A) inversion
B) translocation
C) deletion
D) duplication
E) monosomy

Question 8

A normal male marries a color-blind woman.What percent of their female children will be color-blind?

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

Question 9

The location of a gene on a chromosome is called

A) A locus
B) Homologous
C) A linkage map
D) A linkage group
E) An allele

Question 10

The most common autosomal abnormality present in people is

A) XXX.
B) XXY.
C) XO.
D) a deletion in chromosome 5.
E) an extra chromosome 21.

Question 11

When homologous chromosomes fail to separate during meiosis,this is termed

A) linked genes.
B) disjunction.
C) nondisjunction.
D) crossover.
E) monosomy.

Question 12

Which statement is true regarding the Barr body?

A) It is found in the nuclei of females.
B) It is found in the nuclei of males.
C) It is found in the cytoplasm of males.
D) It is found in the cytoplasm of females.
E) It is a condensed inactive Y chromosome.

Question 13

A male who is color-blind marries a heterozygous woman.What percent of their male children will be color-blind?

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

Question 14

Down syndrome

A) is due to disjunction of chromosomes.
B) individuals have two number 21 chromosomes.
C) may occur at a lower rate in women over 40.
D) can occur if the sperm has an extra number 21 chromosome.
E) persons have normal appearing eyelids.

Question 15

What is the relationship between linked genes and independent assortment?

A) Linked genes show independent assortment.
B) Linked genes do not show independent assortment.
C) Whether or not genes are linked does not influence whether or not they show independent assortment.
D) There is no relationship between linked genes and independent assortment.
E) One of the linked genes will be inherited from the mother and the other one from the father.

Question 16

Which genetic trait is NOT associated with the chromosome involved in Down syndrome?

A) increased incidence of leukemia
B) cataracts
C) mental retardation
D) accelerated aging
E) cystic fibrosis

Question 17

Which of the following would not be the same in a male and female?

A) the total number of autosomes
B) the loci for the majority of their genes
C) the types of sex chromosomes
D) the inheritance of one X chromosome from their mother
E) the need for 2 sex chromosomes

Question 18

If there is complete linkage with genes Ss (for smooth or wrinkled seeds)and Gg (for green or yellow seeds)what phenotypes would you expect in the offspring of a cross with one heterozygous parent (Ss,Gg)which would all produce all smooth and green seeds and a homozygous recessive parent (ss,gg)which would produce all wrinkled yellow seeds?

A) Smooth green seeds or wrinkled yellow seeds only
B) Smooth green seeds only
C) Smooth green seeds, wrinkled yellow seeds, smooth yellow seeds and wrinkled green seeds
D) Wrinkled yellow seeds only

Question 19

If a person has short stature,oriental-like fold of eyelids,fissured tongue and mental retardation,they have

A) cri du chat syndrome.
B) Down syndrome.
C) fragile X syndrome.
D) Turner syndrome.
E) Klinefelter syndrome.

Question 20

A female with two Barr bodies in her cells would have what combination of sex chromosomes?

A) XXY
B) XXXY
C) XXX
D) XX
E) XYY

Question 21

If a chromosomal segment appears more than once in the same chromosome,it is termed a(n)

A) translocation.
B) duplication.
C) deletion.
D) inversion.
E) polyploid.

Question 22

The cri du chat syndrome represents a chromosomal mutation type termed

A) translocation.
B) duplication.
C) deletion.
D) inversion.
E) polyploidy.

Question 23

Which refers to the movement of a piece of one chromosome to another nonhomologous chromosome?

A) inversion
B) translocation
C) deletion
D) duplication
E) monosomy

Question 24

Which refers to the addition of a repeat segment of a chromosome?

A) inversion
B) translocation
C) deletion
D) duplication
E) monosomy

Question 25

Genes on the ___ chromosome determine if the sex of a child will be male or female.

A) X
B) Y
C) 21^st
D) 5^th
E) 19^th

Question 26

A person with an XO genotype is classified as having

A) Down syndrome.
B) cri du chat syndrome.
C) Turner syndrome.
D) Klinefelter syndrome.
E) a poly-X state.

Question 27

If an individual has a XYY genotype,they are classified as having

A) Down syndrome.
B) cri du chat syndrome.
C) Turner syndrome.
D) Klinefelter syndrome.
E) Jacobs syndrome.

Question 28

If an individual has a XXY genotype,they are classified as having

A) Jacobs syndrome.
B) cri du chat syndrome.
C) Turner syndrome.
D) Klinefelter syndrome.
E) a poly-X female state.

Question 29

A female that does not undergo puberty or menstruate or lacks breast development may have

A) Klinefelter syndrome.
B) Down syndrome.
C) cri du chat syndrome.
D) Turner syndrome.
E) poly-X female state.

Question 30

The trait diagrammed in Figure 24.1 is a(n)

A) dominant X-linked trait.
B) recessive X-linked trait.
C) autosomal recessive trait.
D) autosomal dominant trait.
E) dominant Y-linked trait.

Question 31

Generally,it is not possible to determine whether nondisjunction failed to occur in oogenesis or spermatogenesis.However,it is possible to assert that _____ resulted in nondisjunction in ____.

A) XXY; oogenesis
B) XYY; spermatogenesis
C) XXX; oogenesis
D) XXY; spermatogenesis
E) XO; oogenesis

Question 32

The reason that missing chromosomes and extra sex chromosomes do NOT cause more harm than they do is best explained by the

A) inactivation of any X beyond the first as a Barr body.
B) presence of genes on the Y chromosome that determine maleness.
C) presence of genes on the X chromosomes that determine femaleness.
D) loss of a sex chromosome in normal cells as embryo development occurs.
E) a higher level of gene-repair enzyme activity on sex chromosomes.

Question 33

If a chromosomal segment is turned around 180 ^$\circ$ ,the chromosomal mutation is termed a(n)

A) translocation.
B) duplication.
C) deletion.
D) inversion.
E) monosomy.

Question 34

The ____ gene causes mental retardation by increasing the levels of purines in the blood.

A) Gart
B) Dart
C) RFLP
D) SRY
E) Barr

Question 35

If a person inherits two X chromosomes,this individual will be

A) female.
B) male.
C) colorblind.
D) sterile.
E) a poly-X female.

Question 36

If a person has a portion of number 5 chromosome missing,they may have

A) Down syndrome.
B) cri du chat syndrome.
C) Turner syndrome.
D) Klinefelter syndrome.
E) Jacobs syndrome.

Question 37

An individual who has an XXY combination of sex chromosomes is said to have _____ syndrome.

A) Klinefelter
B) Turner
C) Down
D) fragile X
E) cri du chat

Question 38

An XXX female would most likely result from nondisjunction in

A) the mother during egg formation.
B) the father during sperm formation
C) in both the mother and father during gamete formation.
D) the fertilized egg.
E) neither the mother nor the father.

Question 39

Which refers to the loss of a portion of a chromosome?

A) inversion
B) translocation
C) deletion
D) duplication
E) monosomy

Question 40

Considering that males can have Klinefelter (XXY)syndrome,XYY,and normal XY chromosomal combinations,and females can have Turner (XO)syndrome,poly-X (XXX,XXXX),and normal XX combinations,it is obvious that

A) maleness results from the presence of only one X chromosome.
B) maleness results from the absence of two or more X chromosomes.
C) maleness results from the minimal presence of one Y chromosome.
D) femaleness results from the presence of two or more X chromosomes.
E) sex determination is a delicate balance between X and Y chromosomes.

Question 41

Which trait is not part of the linkage group found on chromosome 19?

A) production of elastin
B) Muscular dystrophy
C) hair color (brown)
D) eye color (green/blue)
E) colorectal cancer

Question 42

Describe a genetic disorder associated with a deletion in chromosomal number.

Question 43

In fruit flies,bar eye is inherited by an X-linked allele (B for bar).If a heterozygous bar-eyed female is mated to a nonbar-eyed male,what will be the expected ratio of phenotype given four offspring?

A) two bar-eyed females, two bar-eyed males
B) one bar-eyed and one nonbar-eyed female, one bar-eyed and one nonbar-eyed male
C) three bar-eyed females and one nonbar-eyed male
D) bar-eyed females only
E) nonbar-eyed males only

Question 44

A colorblind (recessive trait)woman will pass the allele to

A) her sons only.
B) all her children.
C) her daughters only.
D) none of her children.
E) her husband.

Question 45

Which of the following conditions is NOT due to a sex-linked gene?

A) color blindness
B) hemophilia
C) muscular dystrophy
D) Klinefelter syndrome
E) inability to see red or green

Question 46

A mother is a carrier for blue eyes (autosomal recessive)and for hemophilia (X-linked recessive).Which of these is a correct statement?

A) All sons will have blue eyes and be hemophiliacs.
B) It depends on the father's genotype whether the sons will have blue eyes and/or be hemophiliacs.
C) The father's genotype can determine whether a son will have blue eyes but cannot determine whether a son will be a hemophiliac.
D) Regardless of the father, no sons will have blue eyes or be hemophiliacs.
E) There is a linkage between eye color and hemophilia.

Question 47

Which of the following sex-linked disorders is characterized by an abnormal number of repeat sequences in the genome?

A) fragile X syndrome
B) hemophilia
C) color blindness
D) Duchenne muscular dystrophy
E) none of these

Question 48

A colorblind (recessive trait)woman will pass the allele to

A) her sons only.
B) all her children.
C) her daughters only.
D) none of her children.
E) her husband.

Question 49

List the four X-linked recessive disorders.

Question 50

Which disorder is characterized by a lack of the protein dystrophin?

A) hemophilia
B) color blindness
C) muscular dystrophy
D) Down syndrome
E) cystic fibrosis

Question 51

If a woman is a carrier for the color blind recessive allele and her husband is normal,what are their chances that a son will be color blind?

A) None since the father is normal.
B) 50%, since the mother is only a carrier.
C) 100% because the mother has the gene.
D) 25% because the mother is a hybrid.
E) None since the son will also be just a carrier.

Question 52

Which genetic disorder is the result of a deletion of a section of an individuals chromosome?

A) Williams syndrome
B) Klinefelter syndrome
C) Down syndrome
D) Turner syndrome
E) None of these are the result of a deletion of a section of an individuals chromosome.

Question 53

Which of the following pairs of alleles would be most likely to cross over?

A)A..........B
B)A...B......
C)A......B.......C
D)AB.............
E)..........AB

Question 54

Which of the following is NOT true about a karyotype?

A) Homologous chromosomes are arranged in pairs.
B) Sex chromosomes are identified separately from autosomes.
C) All chromosome pairs are numbered differently for males and females.
D) Chromosome pairs are assorted by both size and shape.
E) Banding patterns are used in pairing chromosomes.

Question 55

Which of the following sex-linked diseases is characterized by the absence of a clotting factor?

A) hemophilia
B) fragile X syndrome
C) color blindness
D) Duchenne muscular dystrophy
E) none of these

Question 56

Among the disorders caused by changes in chromosome structure are all but one of those listed below; that one is

A) Fragile X syndrome
B) Klinefelter syndrome
C) Williams syndrome
D) Cri du chat syndrome
E) All of these are caused by a change in chromosome structure

Question 57

A karyotype will NOT reveal which of the following genetic diseases?

A) Turner syndrome
B) Klinefelter syndrome
C) Down syndrome
D) cri du chat syndrome
E) hemophilia

Question 58

Hemophilia (h)is a sex-linked recessive trait.If a hemophiliac male marries a carrier female,

A) 50% of their daughters will be hemophiliac.
B) 75% of their daughters will be hemophiliac.
C) 25% of their daughters will be hemophiliac.
D) 25% of their sons will be hemophiliac.
E) 75% of their sons will be hemophiliac.