Question 1

Which antigen, expressed on the surface of all red blood cells, is modified by A- or B-transferases?

Accepted Answer

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Question 2

A metabolic reaction requires 10 units of enzymatic activity to proceed. If a dominant allele D can generate 8 units of enzyme and a recessive allele d can generate 2 units of enzyme, what can be said of the dominant wild-type allele?

Accepted Answer

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Question 3

A metabolic reaction requires 40 units of enzymatic activity to proceed. If a dominant allele D can generate 40 units of enzyme and a mutant allele d" generates 20 units of enzyme, what can be said of the dominant wild-type allele?

Accepted Answer

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Question 4

What are the two categories of gain-of-function mutations?

Accepted Answer

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Question 5

In yeast, there are three gene products required to synthesize the amino acid lysine. You cross two haploid lysine auxotrophs to form a diploid. The diploid fails to grow on plates lacking lysine. Which of the following can you conclude?
A)The haploid strains have mutations in the same gene.
B)The haploid strains have mutations in different genes.
C)The haploid strains form a complementation group.
D)The haploid strains do not complement each other.
E)Both (A)and (D)are true.

Accepted Answer

The diploid's inability to grow on lysine-lacking plates indicates that the mutations are in the same gene, meaning they do not complement each other.

Question 6

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are white with red spots. This is an example of what type of inheritance?

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Question 7

The four different human blood types are caused by how many different alleles? What are the alleles?

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Question 8

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are all pink. This is an example of what type of inheritance?

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Question 9

Which step is catalyzed by the enzyme responsible for the Met 3 mutant? 
A)homoserine → cysteine
B)cysteine → cystathionine
C)cystathionine → homocysteine
D)homocysteine → methionine
E)methionine → homoserine

Accepted Answer

The Met 3 mutation affects the enzyme responsible for converting cysteine to cystathionine, which is step 2 in the methionine biosynthesis pathway. Therefore, the correct answer is B.

Question 10

Individuals with blood type AB have which blood antibody(ies)?

Accepted Answer

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Question 11

An individual who is a "universal acceptor," meaning he or she will not have an adverse reaction to a transfusion with any type of blood, has which blood type?

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Question 12

In the biosynthetic pathway for conversion from homoserine to methionine, you identify a Neurospora crassa double mutant Met1/Met2. This mutant will grow only if which supplement(s)are added to the minimal media? 
A)homoserine only
B)cysteine only
C)homocysteine only
D)cystathionine and homocysteine
E)methionine only

Accepted Answer

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Question 13

Two pure-breeding mutant plants produce white flowers. When they are crossed, all of the progeny have wild-type purple flowers. What does this genetic complementation tell you?
A)The genes are part of distinct biosynthetic pathways.
B)The two lines exhibit different mutations in the same gene.
C)More than one gene is involved in determining the phenotype.
D)The allele is pleiotropic.
E)The allele exhibits incomplete dominance.

Accepted Answer

The fact that the progeny exhibit a wild-type phenotype indicates that both parents had mutations in different genes involved in the same pathway, and that the normal function was restored in the progeny by complementation. If the two lines exhibited different mutations in the same gene, the progeny would still have a mutant phenotype. The presence of a single allele with incomplete dominance or pleiotropic effects would result in an intermediate or altered phenotype, respectively, in the progeny.

Question 14

Alleles of the Sbe1 gene, which controls pea shape, can be detected by DNA analysis. In heterozygous plants, two distinct bands of DNA are visible. What is the relationship between the alleles of the heterozygote at the molecular level?

Accepted Answer

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Question 15

Individuals with blood type A have which blood antigen(s)?

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Question 16

Independent assortment predicts a 9:3:3:1 ratio with four different phenotypes in the F₂ progeny. If the alleles are epistatic, what would you predict? A)more than four phenotypes B)fewer than four phenotypes C)heterozygotes with a novel phenotype between the dominant and recessive homozygotes D)1/3 of the progeny with the dominant phenotypes and 2/3 recessive E)no change in the 9:3:3:1 ratio

Accepted Answer

If the alleles are epistatic, they would interact with each other and affect the expression of certain genes. This would result in fewer than four phenotypes because some of the expected phenotypes would be masked by the interaction between the alleles. For example, if one allele is dominant and masks the expression of the other allele, then only two phenotypes (dominant and recessive) would be observed instead of the expected four.

Question 17

The allele responsible for the Siamese coat-color pattern produces an unstable tyrosinase enzyme. This type of gene product is an example of what type of allele?

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Question 18

Are loss-of-function mutations more likely to be dominant or recessive?

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Question 19

Deafness is caused by recessive mutations in any one of at least five genes. Two deaf individuals have nine children, all of whom have normal hearing. Which of the following can you conclude?
A)The parents have mutations in the same gene.
B)The parents have mutations in different genes.
C)An epistatic interaction has occurred.
D)The mutations are codominant to the normal allele.
E)The mutations are incompletely dominant to the normal allele.

Accepted Answer

If the parents had mutations in the same gene, all of their children would inherit at least one mutated copy of the gene and would therefore have a 25% chance of being deaf. Since all of their children have normal hearing, it is more likely that the parents have mutations in different genes. This would mean that each parent is heterozygous for a different deafness-causing mutation and the normal allele masks the effects of the mutations in their children. An epistatic interaction, codominance, or incomplete dominance would not explain the observed pattern of inheritance.

Question 20

What are the three categories of loss-of-function mutations?

Accepted Answer

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Quiz 4: Gene Interaction

Which antigen, expressed on the surface of all red blood cells, is modified by A- or B-transferases?

A metabolic reaction requires 10 units of enzymatic activity to proceed. If a dominant allele D can generate 8 units of enzyme and a recessive allele d can generate 2 units of enzyme, what can be said of the dominant wild-type allele?

A metabolic reaction requires 40 units of enzymatic activity to proceed. If a dominant allele D can generate 40 units of enzyme and a mutant allele d" generates 20 units of enzyme, what can be said of the dominant wild-type allele?

What are the two categories of gain-of-function mutations?

In yeast, there are three gene products required to synthesize the amino acid lysine. You cross two haploid lysine auxotrophs to form a diploid. The diploid fails to grow on plates lacking lysine. Which of the following can you conclude?

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are white with red spots. This is an example of what type of inheritance?

The four different human blood types are caused by how many different alleles? What are the alleles?

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are all pink. This is an example of what type of inheritance?

Which step is catalyzed by the enzyme responsible for the Met 3 mutant?

Individuals with blood type AB have which blood antibody(ies)?

An individual who is a "universal acceptor," meaning he or she will not have an adverse reaction to a transfusion with any type of blood, has which blood type?

In the biosynthetic pathway for conversion from homoserine to methionine, you identify a Neurospora crassa double mutant Met1/Met2. This mutant will grow only if which supplement(s) are added to the minimal media?

Two pure-breeding mutant plants produce white flowers. When they are crossed, all of the progeny have wild-type purple flowers. What does this genetic complementation tell you?

Alleles of the Sbe1 gene, which controls pea shape, can be detected by DNA analysis. In heterozygous plants, two distinct bands of DNA are visible. What is the relationship between the alleles of the heterozygote at the molecular level?

Individuals with blood type A have which blood antigen(s)?

Independent assortment predicts a 9:3:3:1 ratio with four different phenotypes in the F₂ progeny. If the alleles are epistatic, what would you predict?

The allele responsible for the Siamese coat-color pattern produces an unstable tyrosinase enzyme. This type of gene product is an example of what type of allele?

Are loss-of-function mutations more likely to be dominant or recessive?

Deafness is caused by recessive mutations in any one of at least five genes. Two deaf individuals have nine children, all of whom have normal hearing. Which of the following can you conclude?

What are the three categories of loss-of-function mutations?

Quiz 4: Gene Interaction

Which antigen, expressed on the surface of all red blood cells, is modified by A- or B-transferases?

A metabolic reaction requires 10 units of enzymatic activity to proceed. If a dominant allele D can generate 8 units of enzyme and a recessive allele d can generate 2 units of enzyme, what can be said of the dominant wild-type allele?

A metabolic reaction requires 40 units of enzymatic activity to proceed. If a dominant allele D can generate 40 units of enzyme and a mutant allele d" generates 20 units of enzyme, what can be said of the dominant wild-type allele?

What are the two categories of gain-of-function mutations?

In yeast, there are three gene products required to synthesize the amino acid lysine. You cross two haploid lysine auxotrophs to form a diploid. The diploid fails to grow on plates lacking lysine. Which of the following can you conclude?

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are white with red spots. This is an example of what type of inheritance?

The four different human blood types are caused by how many different alleles? What are the alleles?

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are all pink. This is an example of what type of inheritance?

Which step is catalyzed by the enzyme responsible for the Met 3 mutant?

Individuals with blood type AB have which blood antibody(ies)?

An individual who is a "universal acceptor," meaning he or she will not have an adverse reaction to a transfusion with any type of blood, has which blood type?

In the biosynthetic pathway for conversion from homoserine to methionine, you identify a Neurospora crassa double mutant Met1/Met2. This mutant will grow only if which supplement(s) are added to the minimal media?

Two pure-breeding mutant plants produce white flowers. When they are crossed, all of the progeny have wild-type purple flowers. What does this genetic complementation tell you?

Alleles of the Sbe1 gene, which controls pea shape, can be detected by DNA analysis. In heterozygous plants, two distinct bands of DNA are visible. What is the relationship between the alleles of the heterozygote at the molecular level?

Individuals with blood type A have which blood antigen(s)?

Independent assortment predicts a 9:3:3:1 ratio with four different phenotypes in the F2 progeny. If the alleles are epistatic, what would you predict?

The allele responsible for the Siamese coat-color pattern produces an unstable tyrosinase enzyme. This type of gene product is an example of what type of allele?

Are loss-of-function mutations more likely to be dominant or recessive?

Deafness is caused by recessive mutations in any one of at least five genes. Two deaf individuals have nine children, all of whom have normal hearing. Which of the following can you conclude?

What are the three categories of loss-of-function mutations?

Independent assortment predicts a 9:3:3:1 ratio with four different phenotypes in the F₂ progeny. If the alleles are epistatic, what would you predict?