Question 1

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

Accepted Answer

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. 
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 2

Down syndrome

Accepted Answer

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. 
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 3

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

Accepted Answer

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

Question 4

The trait diagrammed in Figure 24.1 is a(n)

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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. 
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 7

What is the relationship between linked genes and independent assortment?

Accepted Answer

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. 
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 8

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

Accepted Answer

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

Question 9

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 ____.

Accepted Answer

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

Question 10

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

Accepted Answer

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

Question 11

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?

Accepted Answer

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 
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 12

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

Accepted Answer

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

Question 13

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

Accepted Answer

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

Question 14

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

Accepted Answer

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

Question 15

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

Accepted Answer

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 
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 16

A person with an XO genotype is classified as having

Accepted Answer

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

Question 17

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

Accepted Answer

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. 
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 18

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

Accepted Answer

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

Question 19

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?

Accepted Answer

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 
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 20

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

Accepted Answer

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. 
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.

Exam 24: Chromosomal Basis of Inheritance

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

Down syndrome

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

The trait diagrammed in Figure 24.1 is a(n)

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

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

What is the relationship between linked genes and independent assortment?

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

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 ____.

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

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

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

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

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

A person with an XO genotype is classified as having

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

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

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

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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 .