Question 1

Which statement is NOT true about Down syndrome?

Accepted Answer

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. 
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. B

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. D

Question 3

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

Accepted Answer

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

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

A) fragile X syndrome 
B) hemophilia 
C) color-blindness 
D) Duchenne muscular dystrophy 
E) None of the answer choices is true. 
A) fragile X syndrome 
B) hemophilia 
C) color-blindness 
D) Duchenne muscular dystrophy 
E) None of the answer choices is true.

Question 6

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 7

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 8

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 9

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

Accepted Answer

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

Question 10

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

Accepted Answer

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. 
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 11

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

Accepted Answer

A) None,because 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. 
A) None,because 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 12

An XXX female would most likely result from nondisjunction in

Accepted Answer

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. 
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 13

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 14

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

Accepted Answer

A) hemophilia 
B) fragile X syndrome 
C) color-blindness 
D) Duchenne muscular dystrophy 
E) None of the answer choices is true. 
A) hemophilia 
B) fragile X syndrome 
C) color-blindness 
D) Duchenne muscular dystrophy 
E) None of the answer choices is true.

Question 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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

Accepted Answer

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. 
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.

Question 19

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

Accepted Answer

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

Question 20

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

Exam 24: Chromosomal Inheritance and Genetic Disorders

Which statement is NOT true about Down syndrome?

Down syndrome

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

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

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

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

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

A person with an XO genotype is classified as having

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

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

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

An XXX female would most likely result from nondisjunction in

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

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

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

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

If a chromosomal segment is turned around 180 °\degree° ,the chromosomal mutation is termed a(n)

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

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

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 ____.

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

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 .