Question 1

Which of the following statements is NOT true with regard to Huntington disease?

Accepted Answer

A)  The discovery of the gene has led to a test that can identify people who will have the disease before they show symptoms. 
B)  The disease can be traced using pedigrees. 
C)  Now that the gene is known, a cure has been found. 
D)  The gene for Huntington disease is located on chromosome 4. 
A)  The discovery of the gene has led to a test that can identify people who will have the disease before they show symptoms. 
B)  The disease can be traced using pedigrees. 
C)  Now that the gene is known, a cure has been found. 
D)  The gene for Huntington disease is located on chromosome 4. C

Question 2

The following figure contains a pedigree for brachydactyly,an autosomal dominant disorder.Which of the following is true?

Accepted Answer

A)  Individual 5 in Generation II inherited brachydactyly from her mother. 
B)  Individual 2 in Generation II is a carrier of brachydactyly. 
C)  Individual 5 in Generation III cannot pass brachydactyly to his offspring. 
D)  Individual 8 in Generation IV is an affected female. 
A)  Individual 5 in Generation II inherited brachydactyly from her mother. 
B)  Individual 2 in Generation II is a carrier of brachydactyly. 
C)  Individual 5 in Generation III cannot pass brachydactyly to his offspring. 
D)  Individual 8 in Generation IV is an affected female. C

Question 3

Which of the following decreases the probable variation between individuals?

Accepted Answer

A)  independent assortment of chromosomes 
B)  crossing-over 
C)  genetic linkage 
D)  random fertilization of gametes 
A)  independent assortment of chromosomes 
B)  crossing-over 
C)  genetic linkage 
D)  random fertilization of gametes C

Question 4

Human males have one chromosome that females do not,known as the ________ chromosome.

Accepted Answer

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

Question 5

During meiosis,"new" chromosomes are generated when homologous chromosomes exchange genetic material during ________.

Accepted Answer

The answer of During meiosis,"new" chromosomes are generated when homologous...

Question 6

A genetically normal human who has a homozygous genotype for a gene locus on the X chromosome

Accepted Answer

A)  must be a male. 
B)  must be a female. 
C)  cannot be a female. 
D)  may be either male or female. 
A)  must be a male. 
B)  must be a female. 
C)  cannot be a female. 
D)  may be either male or female.

Question 7

The allele responsible for causing Huntington disease is

Accepted Answer

A)  dominant. 
B)  recessive. 
C)  sex-linked. 
D)  not heritable. 
A)  dominant. 
B)  recessive. 
C)  sex-linked. 
D)  not heritable.

Question 8

Recessive genetic disorders are quickly eliminated from human populations because people who have them die before they can reproduce.

Accepted Answer

A) True 
 B)False

Question 9

The chance that any two siblings will be genetically identical is astronomically small.

Accepted Answer

A) True 
 B)False

Question 10

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 have 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 have the disease. 
D)  The homozygous-recessive individuals give their alleles to other individuals before they die from the disease.

Question 11

We now know that the gene for flower color and the gene for seed color are both on chromosome 1 of the pea plants once studied by Mendel.According to Mendel's results,flower color and seed color undergo independent assortment.Which of the following explanations is most likely?

Accepted Answer

A)  Nonhomologous chromosomes containing the two genes underwent crossing-over to create a new "hybrid" chromosome containing both genes. 
B)  During a round of meiosis, the female part of a flower failed to separate a homologous pair, forcing the seed color gene to pair up with the flower color gene. 
C)  Between the time that Mendel studied peas and modern times, one of the genes was translocated onto chromosome 1, so that in modern times, two genes that were once on separate chromosomes are now linked. 
D)  These genes are so far apart on chromosome 1 that they undergo independent assortment. 
A)  Nonhomologous chromosomes containing the two genes underwent crossing-over to create a new "hybrid" chromosome containing both genes. 
B)  During a round of meiosis, the female part of a flower failed to separate a homologous pair, forcing the seed color gene to pair up with the flower color gene. 
C)  Between the time that Mendel studied peas and modern times, one of the genes was translocated onto chromosome 1, so that in modern times, two genes that were once on separate chromosomes are now linked. 
D)  These genes are so far apart on chromosome 1 that they undergo independent assortment.

Question 12

The following diagrams show the same cell,but the homologous pairs are arranged differently in each diagram.The different arrangements of the homologous pairs in version A compared with version B provide an example of the concept of ________.

Accepted Answer

independen

Question 13

Two gametes that are both diploid for the sex chromosomes join to form a zygote.Which of the following genotypes would result?

Accepted Answer

A)  XXXX 
B)  XXY 
C)  X 
D)  XX 
A)  XXXX 
B)  XXY 
C)  X 
D)  XX

Question 14

Genes A and B are located on the same chromosome.Two parent organisms with the genotypes AABB and aabb were crossed.One of the resulting AaBb offspring was experimentally crossed with an aabb individual.The final offspring genotypes were AaBb,aabb,Aabb,and aaBb. Which of the final offspring genotypes were produced through crossing-over?

Accepted Answer

A)  None of the genotypes were produced through crossing-over. 
B)  All of the genotypes were produced through crossing-over. 
C)  AaBb and aabb 
D)  Aabb and aaBb 
A)  None of the genotypes were produced through crossing-over. 
B)  All of the genotypes were produced through crossing-over. 
C)  AaBb and aabb 
D)  Aabb and aaBb

Question 15

All genes on the same chromosome are linked.

Accepted Answer

A) True 
 B)False

Question 16

Because chromosomal alterations such as duplications often affect several genes,they tend to have serious impacts,including slowed growth and mental retardation.

Accepted Answer

A) True 
 B)False

Question 17

The "actual results" in the experiment depicted in the following figure differ significantly from the "expected results" predicted by Mendel's laws because the gene for body color and the gene for wing length

Accepted Answer

A)  are both recessive. 
B)  are close together on a single chromosome. 
C)  undergo independent assortment. 
D)  are located on completely opposite ends of the same chromosome. 
A)  are both recessive. 
B)  are close together on a single chromosome. 
C)  undergo independent assortment. 
D)  are located on completely opposite ends of the same chromosome.

Question 18

Among children with parents who are both carriers of Tay-Sachs,an autosomal recessive disorder,chances are that

Accepted Answer

A)  75 percent will be carriers. 
B)  50 percent will die in a few years. 
C)  75 percent will not carry the recessive Tay-Sachs's allele. 
D)  50 percent will be carriers. 
A)  75 percent will be carriers. 
B)  50 percent will die in a few years. 
C)  75 percent will not carry the recessive Tay-Sachs's allele. 
D)  50 percent will be carriers.

Question 19

All inherited diseases are the result of mutations of single genes.

Accepted Answer

A) True 
 B)False

Question 20

The farther apart on the same chromosome that two genes are located,the more likely they are to undergo ________.

Accepted Answer

recombination,crossi

Exam 10: Chromosomes and Human Genetics

Which of the following statements is NOT true with regard to Huntington disease?

The following figure contains a pedigree for brachydactyly,an autosomal dominant disorder.Which of the following is true?

Which of the following decreases the probable variation between individuals?

Human males have one chromosome that females do not,known as the ________ chromosome.

During meiosis,"new" chromosomes are generated when homologous chromosomes exchange genetic material during ________.

A genetically normal human who has a homozygous genotype for a gene locus on the X chromosome

The allele responsible for causing Huntington disease is

Recessive genetic disorders are quickly eliminated from human populations because people who have them die before they can reproduce.

The chance that any two siblings will be genetically identical is astronomically small.

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?

We now know that the gene for flower color and the gene for seed color are both on chromosome 1 of the pea plants once studied by Mendel.According to Mendel's results,flower color and seed color undergo independent assortment.Which of the following explanations is most likely?

The following diagrams show the same cell,but the homologous pairs are arranged differently in each diagram.The different arrangements of the homologous pairs in version A compared with version B provide an example of the concept of ________.

Two gametes that are both diploid for the sex chromosomes join to form a zygote.Which of the following genotypes would result?

All genes on the same chromosome are linked.

Because chromosomal alterations such as duplications often affect several genes,they tend to have serious impacts,including slowed growth and mental retardation.

The "actual results" in the experiment depicted in the following figure differ significantly from the "expected results" predicted by Mendel's laws because the gene for body color and the gene for wing length

Among children with parents who are both carriers of Tay-Sachs,an autosomal recessive disorder,chances are that

All inherited diseases are the result of mutations of single genes.

The farther apart on the same chromosome that two genes are located,the more likely they are to undergo ________.

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