Question 1

A mutation at a single locus causes a change in many different characters. This an example of a(n) _______ effect.

Accepted Answer

A)  polygene 
B)  epigenetic 
C)  cytoplasmic 
D)  multiple negativity 
E)  pleiotropic 
A)  polygene 
B)  epigenetic 
C)  cytoplasmic 
D)  multiple negativity 
E)  pleiotropic E

Question 2

Genetic mutations are

Accepted Answer

A)  rare. 
B)  stable. 
C)  inherited changes in DNA. 
D)  random. 
E)  All of the above 
A)  rare. 
B)  stable. 
C)  inherited changes in DNA. 
D)  random. 
E)  All of the above E

Question 3

Which statement about an individual that is homozygous for an allele is not true?

Accepted Answer

A)  Each of its cells possesses two copies of that allele. 
B)  Each of its gametes contains one copy of that allele. 
C)  It is true-breeding with respect to that allele. 
D)  Its parents were necessarily homozygous for that allele. 
E)  It can pass that allele to its offspring. 
A)  Each of its cells possesses two copies of that allele. 
B)  Each of its gametes contains one copy of that allele. 
C)  It is true-breeding with respect to that allele. 
D)  Its parents were necessarily homozygous for that allele. 
E)  It can pass that allele to its offspring. D

Question 4

How many autosomes do humans have?

Accepted Answer

A)  23 pairs 
B)  22 pairs 
C)  1 pair 
D)  45 
E)  16 
A)  23 pairs 
B)  22 pairs 
C)  1 pair 
D)  45 
E)  16

Question 5

The genotype of an organism that expresses a dominant trait can be determined by

Accepted Answer

A)  crossing the organism with a homozygous dominant organism. 
B)  crossing the organism with a heterozygous dominant organism. 
C)  crossing the organism with a homozygous recessive organism. 
D)  observing the phenotype of the progeny from any cross. 
E)  observing the genotype of the progeny from any cross. 
A)  crossing the organism with a homozygous dominant organism. 
B)  crossing the organism with a heterozygous dominant organism. 
C)  crossing the organism with a homozygous recessive organism. 
D)  observing the phenotype of the progeny from any cross. 
E)  observing the genotype of the progeny from any cross.

Question 6

Consider a, b, and c, different genes that all reside on the same chromosome. Genes a and b are 10 cM apart, b and c are 2 cM apart, and a and c are 8 cM apart. What is the order of these genes?

Accepted Answer

A)  a, b, c 
B)  a, c, b 
C)  b, a, c 
D)  c, a, b 
E)  The order cannot be determined from the information given. 
A)  a, b, c 
B)  a, c, b 
C)  b, a, c 
D)  c, a, b 
E)  The order cannot be determined from the information given.

Question 7

Which of the following statements about Mendelian genetics is false?

Accepted Answer

A)  Alternative forms of genes are called alleles. 
B)  A locus is a gene's location on its chromosome. 
C)  Only two alleles can exist for a given gene. 
D)  A genotype is a description of the alleles that represent an individual's genes. 
E)  Individuals with the same phenotype can have different genotypes. 
A)  Alternative forms of genes are called alleles. 
B)  A locus is a gene's location on its chromosome. 
C)  Only two alleles can exist for a given gene. 
D)  A genotype is a description of the alleles that represent an individual's genes. 
E)  Individuals with the same phenotype can have different genotypes.

Question 8

If two strains of true-breeding plants that have different alleles for a certain character are crossed, their progeny are called

Accepted Answer

A)  the P generation. 
B)  the F1 generation. 
C)  the F2 generation. 
D)  F1 crosses. 
E)  F2 progeny. 
A)  the P generation. 
B)  the F1 generation. 
C)  the F2 generation. 
D)  F1 crosses. 
E)  F2 progeny.

Question 9

During what year did Gregor Mendel orally present his genetics project?

Accepted Answer

A)  1565 
B)  1665 
C)  1765 
D)  1865 
E)  1965 
A)  1565 
B)  1665 
C)  1765 
D)  1865 
E)  1965

Question 10

Mendel's crossing of spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is

Accepted Answer

A)  codominant. 
B)  dominant. 
C)  recessive. 
D)  Both a and b 
E)  Both a and c 
A)  codominant. 
B)  dominant. 
C)  recessive. 
D)  Both a and b 
E)  Both a and c

Question 11

The cross AaBb $\times$ AaBb is an example of a _______ cross and the results of such crosses led Mendel to propose what we now call the _______.

Accepted Answer

A)  selfcross; law of segregation of genes 
B)  dihybrid cross; law of segregation of genes 
C)  dihybrid cross; law of independent assortment 
D)  test cross; law of segregation of genes 
E)  test cross; law of independent assortment 
A)  selfcross; law of segregation of genes 
B)  dihybrid cross; law of segregation of genes 
C)  dihybrid cross; law of independent assortment 
D)  test cross; law of segregation of genes 
E)  test cross; law of independent assortment

Question 12

A dramatic departure from expected phenotypic ratios may be the result of

Accepted Answer

A)  environmental influences. 
B)  linkage. 
C)  epistasis. 
D)  gene interactions. 
E)  All of the above 
A)  environmental influences. 
B)  linkage. 
C)  epistasis. 
D)  gene interactions. 
E)  All of the above

Question 13

Linked genes are genes that

Accepted Answer

A)  assort independently. 
B)  segregate equally in the gametes during meiosis. 
C)  always contribute the same trait to the zygote. 
D)  are found on the same chromosome. 
E)  recombine during mitosis. 
A)  assort independently. 
B)  segregate equally in the gametes during meiosis. 
C)  always contribute the same trait to the zygote. 
D)  are found on the same chromosome. 
E)  recombine during mitosis.

Question 14

_______ is the term for an allele that has more than one distinguishable phenotypic effect.

Accepted Answer

A)  Pleiotropy 
B)  Incomplete dominance 
C)  Codominance 
D)  Epistasis 
E)  Heterosis 
A)  Pleiotropy 
B)  Incomplete dominance 
C)  Codominance 
D)  Epistasis 
E)  Heterosis

Question 15

A test cross

Accepted Answer

A)  is used to determine if an organism that is displaying a dominant trait is heterozygous or homozygous for that trait. 
B)  is used to determine if an organism that is displaying a recessive trait is heterozygous or homozygous for that trait. 
C)  causes the loss of hybrid vigor. 
D)  results in an F2 generation with a phenotypic ratio of 3/4 dominant to 1/4 recessive. 
E)  results in the same alleles being transferred from generation to generation. 
A)  is used to determine if an organism that is displaying a dominant trait is heterozygous or homozygous for that trait. 
B)  is used to determine if an organism that is displaying a recessive trait is heterozygous or homozygous for that trait. 
C)  causes the loss of hybrid vigor. 
D)  results in an F2 generation with a phenotypic ratio of 3/4 dominant to 1/4 recessive. 
E)  results in the same alleles being transferred from generation to generation.

Question 16

Plasmids are used to

Accepted Answer

A)  break down hydrocarbons. 
B)  clean up oil spills. 
C)  produce clones. 
D)  insert new genetic information into cells. 
E)  All of the above 
A)  break down hydrocarbons. 
B)  clean up oil spills. 
C)  produce clones. 
D)  insert new genetic information into cells. 
E)  All of the above

Question 17

The genetic sex of a human is determined by

Accepted Answer

A)  ploidy, with the male being haploid. 
B)  the Y chromosome. 
C)  X and Y chromosomes, the male being XX. 
D)  the number of X chromosomes, the male being XO. 
E)  Z and W chromosomes, the male being ZZ. 
A)  ploidy, with the male being haploid. 
B)  the Y chromosome. 
C)  X and Y chromosomes, the male being XX. 
D)  the number of X chromosomes, the male being XO. 
E)  Z and W chromosomes, the male being ZZ.

Question 18

Sex determination in birds and mammals is similar except that in birds, females are _______ while in mammals, females are _______.

Accepted Answer

A)  heterogametic; homogametic 
B)  homogametic; heterogametic 
C)  haploid; heterogametic 
D)  diploid; heterogametic 
E)  None of the above 
A)  heterogametic; homogametic 
B)  homogametic; heterogametic 
C)  haploid; heterogametic 
D)  diploid; heterogametic 
E)  None of the above

Question 19

What is the pattern of inheritance for a rare recessive allele?

Accepted Answer

A)  Every affected person has an affected parent. 
B)  Unaffected parents can produce children who are affected. 
C)  Affected parents do not produce affected children. 
D)  Unaffected mothers have affected sons and daughters who are carriers. 
E)  None of the above 
A)  Every affected person has an affected parent. 
B)  Unaffected parents can produce children who are affected. 
C)  Affected parents do not produce affected children. 
D)  Unaffected mothers have affected sons and daughters who are carriers. 
E)  None of the above

Question 20

In dogs, phenotype A (erect ears and barking while following a scent) is caused by dominant alleles; phenotype B (droopy ears and silent while following a scent) is caused by recessive alleles. A dog that is homozygous for both traits of phenotype A is mated to a dog with phenotype B. If the genes for the two traits are unlinked, which of the following is (are) the expected F1 phenotypic ratio(s)?

Accepted Answer

A)  9:3:3:1 
B)  1:1 
C)  16:0 
D)  1:2:1 
E)  None of the above 
A)  9:3:3:1 
B)  1:1 
C)  16:0 
D)  1:2:1 
E)  None of the above

Exam 12: Inheritance, Genes, and Chromosomes

A mutation at a single locus causes a change in many different characters. This an example of a(n) _______ effect.

Genetic mutations are

Which statement about an individual that is homozygous for an allele is not true?

How many autosomes do humans have?

The genotype of an organism that expresses a dominant trait can be determined by

Consider a, b, and c, different genes that all reside on the same chromosome. Genes a and b are 10 cM apart, b and c are 2 cM apart, and a and c are 8 cM apart. What is the order of these genes?

Which of the following statements about Mendelian genetics is false?

If two strains of true-breeding plants that have different alleles for a certain character are crossed, their progeny are called

During what year did Gregor Mendel orally present his genetics project?

Mendel's crossing of spherical-seeded pea plants with wrinkled-seeded pea plants resulted in progeny that all had spherical seeds. This indicates that the wrinkled-seed trait is

The cross AaBb ×\times× AaBb is an example of a _______ cross and the results of such crosses led Mendel to propose what we now call the _______.

A dramatic departure from expected phenotypic ratios may be the result of

Linked genes are genes that

_______ is the term for an allele that has more than one distinguishable phenotypic effect.

A test cross

Plasmids are used to

The genetic sex of a human is determined by

Sex determination in birds and mammals is similar except that in birds, females are _______ while in mammals, females are _______.

What is the pattern of inheritance for a rare recessive allele?

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The cross AaBb $\times$ AaBb is an example of a _ cross and the results of such crosses led Mendel to propose what we now call the _.

Sex determination in birds and mammals is similar except that in birds, females are _ while in mammals, females are _.