Question 1

The most reasonable explanation for the fact that disorders such as cystic fibrosis do not disappear from the human population is that

Accepted Answer

A)  it is an autosomal dominant disease. 
B)  new medical procedures allow most sufferers to live long enough to pass the gene on to offspring. 
C)  heterozygous carriers have one normal gene that masks the harmful gene. 
D)  the gene keeps mutating back to the harmful form. 
E)  persons with cystic fibrosis are made stronger by their affliction. 
A)  it is an autosomal dominant disease. 
B)  new medical procedures allow most sufferers to live long enough to pass the gene on to offspring. 
C)  heterozygous carriers have one normal gene that masks the harmful gene. 
D)  the gene keeps mutating back to the harmful form. 
E)  persons with cystic fibrosis are made stronger by their affliction.

Question 2

Pattern baldness is a trait that is referred to as sex-

Accepted Answer

A)  linked. 
B)  related. 
C)  retarded. 
D)  influenced. 
E)  matched. 
A)  linked. 
B)  related. 
C)  retarded. 
D)  influenced. 
E)  matched.

Question 3

In genetic analyses, researchers know that linkage of genes will introduce exceptions to the principle of

Accepted Answer

A)  dominance. 
B)  segregation. 
C)  recessiveness. 
D)  independent assortment. 
E)  chromosomal inheritance. 
A)  dominance. 
B)  segregation. 
C)  recessiveness. 
D)  independent assortment. 
E)  chromosomal inheritance.

Question 4

Genes that are located on the same chromosome may

Accepted Answer

A)  tend to be inherited together. 
B)  appear together in the gamete. 
C)  be linked. 
D)  be separated during crossing over. 
E)  all of these 
A)  tend to be inherited together. 
B)  appear together in the gamete. 
C)  be linked. 
D)  be separated during crossing over. 
E)  all of these

Question 5

In karyotyping, individual chromosomes may be distinguished from others by

Accepted Answer

A)  a comparison of chromosome lengths. 
B)  bands produced on chromosomes by differential staining. 
C)  the position of centromeres. 
D)  the relative lengths of the "arms." 
E)  all of these. 
A)  a comparison of chromosome lengths. 
B)  bands produced on chromosomes by differential staining. 
C)  the position of centromeres. 
D)  the relative lengths of the "arms." 
E)  all of these.

Question 6

The pattern illustrating autosomal dominant inheritance is labeled by the letter ____.

Accepted Answer

The answer of   
 The pattern illustrating autosomal...

Question 7

Because of genetic differences in people's responses to medications, there are over 100 different types of

Accepted Answer

A)  antibiotics. 
B)  muscle relaxers. 
C)  tranquilizers. 
D)  blood pressure medications. 
E)  stimulants. 
A)  antibiotics. 
B)  muscle relaxers. 
C)  tranquilizers. 
D)  blood pressure medications. 
E)  stimulants.

Question 8

Which chemical is used to arrest mitosis at metaphase?

Accepted Answer

A)  Giemsa stain 
B)  acetone 
C)  colchicine 
D)  alcohol 
E)  formaldehyde 
A)  Giemsa stain 
B)  acetone 
C)  colchicine 
D)  alcohol 
E)  formaldehyde

Question 9

If nondisjunction occurs during meiosis,

Accepted Answer

A)  the resulting sex cells will be heterogametes. 
B)  one-half of the resulting cells will exhibit trisomy and the other half monosomy. 
C)  diploid cells will be produced. 
D)  all gametes would lack a chromosome and these gametes would be infertile. 
E)  none of the gametes will be capable of achieving fertilization. 
A)  the resulting sex cells will be heterogametes. 
B)  one-half of the resulting cells will exhibit trisomy and the other half monosomy. 
C)  diploid cells will be produced. 
D)  all gametes would lack a chromosome and these gametes would be infertile. 
E)  none of the gametes will be capable of achieving fertilization.

Question 10

Which of the following would be an exception to the principle of independent assortment?

Accepted Answer

A)  dominance 
B)  recessiveness 
C)  incomplete dominance 
D)  pleiotropy 
E)  linkage 
A)  dominance 
B)  recessiveness 
C)  incomplete dominance 
D)  pleiotropy 
E)  linkage

Question 11

Hemophilia is an X-linked recessive gene. A normal woman whose father had hemophilia marries a normal man. What are the chances of hemophilia in their children?

Accepted Answer

All females normal but 1/2 of

Question 12

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

Accepted Answer

A)  both parents. 
B)  neither parent. 
C)  the father only. 
D)  the mother only. 
E)  It is not possible to determine from the data given. 
A)  both parents. 
B)  neither parent. 
C)  the father only. 
D)  the mother only. 
E)  It is not possible to determine from the data given.

Question 13

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?

Accepted Answer

A)  XX and XY 
B)  XXY and XO 
C)  XYY and XO 
D)  XYY and YO 
E)  XY and XO 
A)  XX and XY 
B)  XXY and XO 
C)  XYY and XO 
D)  XYY and YO 
E)  XY and XO

Question 14

Males tend to be affected in greater numbers by X-linked recessive genetic disorders than are females because

Accepted Answer

A)  females have two dominant genes for the disorder. 
B)  males have only one X chromosomes. 
C)  males have a double dose of the gene. 
D)  Y chromosomes are not as strong as X chromosomes. 
E)  females have two dominant genes for the disorder and males have only one recessive gene for the disorder. 
A)  females have two dominant genes for the disorder. 
B)  males have only one X chromosomes. 
C)  males have a double dose of the gene. 
D)  Y chromosomes are not as strong as X chromosomes. 
E)  females have two dominant genes for the disorder and males have only one recessive gene for the disorder.

Question 15

A human X-linked gene is

Accepted Answer

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. 
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.

Question 16

Which of the following conditions is characterized by a karyotype with 45 chromosomes?

Accepted Answer

A)  Turner syndrome 
B)  Down syndrome 
C)  testicular feminization syndrome 
D)  Klinefelter syndrome 
E)  cri-du-chat 
A)  Turner syndrome 
B)  Down syndrome 
C)  testicular feminization syndrome 
D)  Klinefelter syndrome 
E)  cri-du-chat

Question 17

Which of these terms could be used to describe a person with one normal gene and one gene for a recessive disease?

Accepted Answer

A)  heterozygote 
B)  carrier 
C)  a female 
D)  a male 
E)  homozygote 
A)  heterozygote 
B)  carrier 
C)  a female 
D)  a male 
E)  homozygote

Question 18

Which of the following designates a human male with Klinefelter's Syndrome?

Accepted Answer

A)  XXY 
B)  XY 
C)  XX 
D)  XYY 
E)  XO 
A)  XXY 
B)  XY 
C)  XX 
D)  XYY 
E)  XO

Question 19

The probability of producing a phenotypically normal child by two parents who are carriers for an autosomal recessive disorder is

Accepted Answer

A)  50 percent. 
B)  0 percent. 
C)  100 percent. 
D)  25 percent. 
E)  75 percent. 
A)  50 percent. 
B)  0 percent. 
C)  100 percent. 
D)  25 percent. 
E)  75 percent.

Question 20

If a chromosome's gene sequence is represented by the letters A - B - C - D - E - F - G before modification and A - B - C - D - C - D - E - F - G afterward, this would be an example of

Accepted Answer

A)  inversion. 
B)  deletion. 
C)  duplication. 
D)  translocation. 
E)  crossing over. 
A)  inversion. 
B)  deletion. 
C)  duplication. 
D)  translocation. 
E)  crossing over.

Exam 20: Chromosomes and Human Genetics

The most reasonable explanation for the fact that disorders such as cystic fibrosis do not disappear from the human population is that

Pattern baldness is a trait that is referred to as sex-

In genetic analyses, researchers know that linkage of genes will introduce exceptions to the principle of

Genes that are located on the same chromosome may

In karyotyping, individual chromosomes may be distinguished from others by

The pattern illustrating autosomal dominant inheritance is labeled by the letter ____.

Because of genetic differences in people's responses to medications, there are over 100 different types of

Which chemical is used to arrest mitosis at metaphase?

If nondisjunction occurs during meiosis,

Which of the following would be an exception to the principle of independent assortment?

Hemophilia is an X-linked recessive gene. A normal woman whose father had hemophilia marries a normal man. What are the chances of hemophilia in their children?

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

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?

Males tend to be affected in greater numbers by X-linked recessive genetic disorders than are females because

A human X-linked gene is

Which of the following conditions is characterized by a karyotype with 45 chromosomes?

Which of these terms could be used to describe a person with one normal gene and one gene for a recessive disease?

Which of the following designates a human male with Klinefelter's Syndrome?

The probability of producing a phenotypically normal child by two parents who are carriers for an autosomal recessive disorder is

If a chromosome's gene sequence is represented by the letters A - B - C - D - E - F - G before modification and A - B - C - D - C - D - E - F - G afterward, this would be an example of

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