Question 1

If a father is affected by an X-linked recessive condition and the mother is a carrier,what is the probability of their children being affected?

Accepted Answer

A)  All sons will be affected. 
B)  Half of the sons will be affected. 
C)  All daughters will be affected. 
D)  Half of the sons will be carriers. 
A)  All sons will be affected. 
B)  Half of the sons will be affected. 
C)  All daughters will be affected. 
D)  Half of the sons will be carriers.

Question 2

The X chromosome in humans is

Accepted Answer

A)  found as a pair in females. 
B)  the only human sex chromosome. 
C)  present only in females. 
D)  always found in single copy. 
A)  found as a pair in females. 
B)  the only human sex chromosome. 
C)  present only in females. 
D)  always found in single copy.

Question 3

The genetic disorder followed through the pedigree shown below is

Accepted Answer

A)  recessive and X-linked. 
B)  recessive and autosomal. 
C)  dominant and X-linked. 
D)  dominant and autosomal. 
A)  recessive and X-linked. 
B)  recessive and autosomal. 
C)  dominant and X-linked. 
D)  dominant and autosomal.

Question 4

One chromosomal abnormality that is usually fatal is

Accepted Answer

A)  a mutation in a gene. 
B)  an exchange of material between homologous chromosomes. 
C)  extra copies of sex chromosomes. 
D)  the addition of an extra autosomal chromosome. 
A)  a mutation in a gene. 
B)  an exchange of material between homologous chromosomes. 
C)  extra copies of sex chromosomes. 
D)  the addition of an extra autosomal chromosome.

Question 5

If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce,why doesn't that allele quickly become extinct in the population?

Accepted Answer

A)  Alleles are never lost from a population. 
B)  The homozygous dominant individuals protect the recessive allele in their genomes. 
C)  The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease. 
D)  The homozygous recessive individuals give their alleles to other individuals before they die from the disease. 
A)  Alleles are never lost from a population. 
B)  The homozygous dominant individuals protect the recessive allele in their genomes. 
C)  The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease. 
D)  The homozygous recessive individuals give their alleles to other individuals before they die from the disease.

Question 6

Which of the following best estimates the occurrence of the X-linked recessive disorder Duchenne muscular dystrophy in all births per year as shown in the figure below?

Accepted Answer

A)  0.03 percent 
B)  0.15 percent 
C)  0.015 percent 
D)  0.5 percent 
A)  0.03 percent 
B)  0.15 percent 
C)  0.015 percent 
D)  0.5 percent

Question 7

While examining the pedigree of a human female,you discover that she has 44 autosomes and two sex chromosomes,an X and a Y.This may lead you to suspect that there is a mutation within this individual's ________ gene.

Accepted Answer

The answer of While examining the pedigree of a human...

Question 8

The gene for a certain sex-linked trait is found only on the Y chromosome.If the male parent has this gene,the trait will be expressed in

Accepted Answer

A)  100 percent of the female offspring. 
B)  50 percent of the female offspring. 
C)  100 percent of the male offspring. 
D)  50 percent of the male offspring. 
A)  100 percent of the female offspring. 
B)  50 percent of the female offspring. 
C)  100 percent of the male offspring. 
D)  50 percent of the male offspring.

Question 9

A karyotype of an individual with mild mental retardation shows three copies of the X chromosome.If this individual decides to have children,how is her chromosomal abnormality likely to affect her offspring?

Accepted Answer

A)  All of her children will inherit an extra copy of the X chromosome. 
B)  Any female children have a 75 percent chance of inheriting an extra copy of an X chromosome. 
C)  She will be unable to produce male children. 
D)  Half of her eggs will contain an extra copy of the X chromosome. 
A)  All of her children will inherit an extra copy of the X chromosome. 
B)  Any female children have a 75 percent chance of inheriting an extra copy of an X chromosome. 
C)  She will be unable to produce male children. 
D)  Half of her eggs will contain an extra copy of the X chromosome.

Question 10

In a karyotype of a male,which of the following would indicate an abnormality?

Accepted Answer

A)  one X chromosome and one Y chromosome 
B)  three copies of chromosome 22 
C)  22 pairs of autosomes 
D)  a total of 46 chromosomes 
A)  one X chromosome and one Y chromosome 
B)  three copies of chromosome 22 
C)  22 pairs of autosomes 
D)  a total of 46 chromosomes

Question 11

The genotype of a female carrier of the X-linked recessive gene for Duchene muscular dystrophy is represented as

Accepted Answer

A)  XDY. 
B)  XDXd. 
C)  Xd Y. 
D)  XDXD. 
A)  XDY. 
B)  XDXd. 
C)  Xd Y. 
D)  XDXD.

Question 12

Explain how two brothers might have different X chromosomes,but they must share identical Y chromosomes.

Accepted Answer

Males inherit one of two X chr

Question 13

What information is NOT visible in a karyotype?

Accepted Answer

A)  the individual's sex 
B)  the number of autosomes 
C)  genetic mutations 
D)  chromosomal deletions 
A)  the individual's sex 
B)  the number of autosomes 
C)  genetic mutations 
D)  chromosomal deletions

Question 14

Which of the following is true of the genetic cross shown in the figure below?

Accepted Answer

A)  All of their daughters will be carriers. 
B)  Their sons have a 50 percent chance of being carriers. 
C)  Their sons have a 50 percent chance of having the disorder. 
D)  Their daughters have a 50 percent chance of having the disorder. 
A)  All of their daughters will be carriers. 
B)  Their sons have a 50 percent chance of being carriers. 
C)  Their sons have a 50 percent chance of having the disorder. 
D)  Their daughters have a 50 percent chance of having the disorder.

Question 15

Why are dominant genetic disorders more rare than recessive disorders?

Accepted Answer

Dominant genetic disorders tend to cause

Question 16

Every gene in a human occupies a specific position or ________ on a chromosome.

Accepted Answer

The answer of Every gene in a human occupies a...

Question 17

Which of the following genotypes represents a human male?

Accepted Answer

A)  XY 
B)  YY 
C)  XX 
D)  XO 
A)  XY 
B)  YY 
C)  XX 
D)  XO

Question 18

Human males have one chromosome that females do not.That chromosome is the ________ chromosome.

Accepted Answer

The answer of Human males have one chromosome that females...

Question 19

A female who carries on her X chromosomes one copy of a recessive mutated allele and one normal copy is referred to as a genetic ________.

Accepted Answer

The answer of A female who carries on her X...

Question 20

A karyotype of a human female reveals a total of 45 chromosomes: 44 autosomes and one sex chromosome.Is this karyotype typical of human females? Explain your reasoning.

Accepted Answer

This karyotype is not typical of human f

Exam 8: Chromosomes and Human Genetics

If a father is affected by an X-linked recessive condition and the mother is a carrier,what is the probability of their children being affected?

The X chromosome in humans is

The genetic disorder followed through the pedigree shown below is

One chromosomal abnormality that is usually fatal is

If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce,why doesn't that allele quickly become extinct in the population?

Which of the following best estimates the occurrence of the X-linked recessive disorder Duchenne muscular dystrophy in all births per year as shown in the figure below?

While examining the pedigree of a human female,you discover that she has 44 autosomes and two sex chromosomes,an X and a Y.This may lead you to suspect that there is a mutation within this individual's ________ gene.

The gene for a certain sex-linked trait is found only on the Y chromosome.If the male parent has this gene,the trait will be expressed in

A karyotype of an individual with mild mental retardation shows three copies of the X chromosome.If this individual decides to have children,how is her chromosomal abnormality likely to affect her offspring?

In a karyotype of a male,which of the following would indicate an abnormality?

The genotype of a female carrier of the X-linked recessive gene for Duchene muscular dystrophy is represented as

Explain how two brothers might have different X chromosomes,but they must share identical Y chromosomes.

What information is NOT visible in a karyotype?

Which of the following is true of the genetic cross shown in the figure below?

Why are dominant genetic disorders more rare than recessive disorders?

Every gene in a human occupies a specific position or ________ on a chromosome.

Which of the following genotypes represents a human male?

Human males have one chromosome that females do not.That chromosome is the ________ chromosome.

A female who carries on her X chromosomes one copy of a recessive mutated allele and one normal copy is referred to as a genetic ________.

A karyotype of a human female reveals a total of 45 chromosomes: 44 autosomes and one sex chromosome.Is this karyotype typical of human females? Explain your reasoning.

The Nature of Science

Evaluating Scientific Claims

Chemistry of Life

Life Is Cellular

How Cells Work

Cell Division

Patterns of Inheritance

What Genes Are

How Genes Work

Evidence for Evolution

Mechanisms of Evolution

Adaptation and Species

The History of Life

Bacteria and Archaea

Plants, Fungi, and Protists

Animals and Human Evolution

General Principles of Ecology

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