Multiple Choice Questions

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?
  • 1:1:1:1
  • 25%
  • 1:1
  • 50%
An individual heterozygous for cystic fibrosis
  • incomplete dominance
  • is a carrier
  • wild-type trait
  • linked genes
Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are
  • located close together on a chromosome
  • influenced by both genes and the environment
  • The yellow allele is dominant to the green allele
  • is homozygous recessive for that trait
Red-green color blindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. Can a man with normal color vision father a daughter who is red-green color-blind?
  • Mendel's law of independent assortment
  • gametes have one allele copy for each gene
  • The yellow allele is dominant to the green allele
  • No, he can't (unless there is a mutation).
In humans, free earlobes (E) are dominant to attached earlobes (e) and the presence of freckles (F) is dominant to the absence of freckles (f). If an individual heterozygous for both of these traits were to mate with an individual with attached earlobes and no freckles, what is the probability of having a child with attached earlobes and freckles?
  • 25%
  • 3:1
  • 0%
  • Dd
Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome. A man with three nostrils has a daughter who has a son with a man who has only two nostrils. What is the probability that the three-nostriled man's grandson has three nostrils?
  • 50%
  • Dd
  • 3%
  • 0%
Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual?
  • AA × aa
  • 3:1
  • pleiotropy
  • 1:1:1:1
Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. Of what type of inheritance is the phenotype of Marfan syndrome an example?
  • heterozygotes... dominant
  • pedigree
  • 1:1:1:1
  • pleiotropy
Which of these crosses will produce only heterozygous offspring?
  • AA × aa
  • linked genes
  • Linked
  • amniocentesis
Experience with dog breeding has taught geneticists ________.
  • The heterozygote expresses the phenotype of both homozygotes.
  • that geographically isolated groups of dogs may be selected for quite different traits, resulting in a different dog breed
  • self-fertilizes to produce offspring identical to the parent
  • the behavior of chromosomes during metaphase I and anaphase I of meiosis
The ________ is most commonly found in nature.
  • self-fertilizes to produce offspring identical to the parent
  • Linked
  • amniocentesis
  • wild-type trait
Alleles are described as
  • located close together on a chromosome
  • The heterozygote expresses the phenotype of both homozygotes.
  • linked genes
  • alternate versions of a gene
A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds. The F1 plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F1 × F1 cross?
  • DBC
  • 3:1
  • 1:1
  • 3%
According to Mendel's law of segregation, ________.
  • The heterozygote expresses the phenotype of both homozygotes.
  • gametes have one allele copy for each gene
  • codominance
  • carries two copies of the same allele for a gene
Hypophosphatemia (vitamin D—resistant rickets) is inherited as a sex-linked dominant trait. The relevant gene is found on the X chromosome. What is the expected outcome of a cross between a homozygous recessive woman and a man with hypophosphatemia?
  • All of their daughters and none of their sons exhibit hypophosphatemia.
  • The yellow allele is dominant to the green allele
  • the behavior of chromosomes during metaphase I and anaphase I of meiosis
  • The trait varies along a continuum in the population.
Mendel crossed purebred purple-flowered plants with purebred white-flowered plants, and all of the resulting offspring produced purple flowers. The offspring are all ________, and the allele for purple flowers is
  • pleiotropy
  • heterozygotes... dominant
  • The heterozygote expresses the phenotype of both homozygotes.
  • amniocentesis
An individual who is homozygous
  • is a carrier
  • codominance
  • incomplete dominance
  • carries two copies of the same allele for a gene
What name is given to the specific location of a gene on a chromosome?
  • AA × aa
  • pedigree
  • locus
  • Linked
A couple has two female children. What is the probability that their next child will be male?
  • 1:1
  • 25%
  • 3%
  • 50%
What is the key to the recognition of incomplete dominance?
  • The heterozygote expresses the phenotype of both homozygotes.
  • the behavior of chromosomes during metaphase I and anaphase I of meiosis
  • The phenotype of the heterozygote falls between the phenotypes of the homozygotes.
  • The trait varies along a continuum in the population.
Which of the following techniques is used to collect fetal cells during pregnancy for genetic testing?
  • linked genes
  • AA × aa
  • height
  • amniocentesis
Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?
  • 3:1
  • 0%
  • 1:1
  • 50%
An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy hair. What is the relationship between the alleles for hair texture?
  • pleiotropy
  • is a carrier
  • 0%
  • incomplete dominance
The recombination frequency between gene B and gene C is 11%. The recombination frequency between gene B and gene D is 5%. The recombination frequency between gene C and gene D is 15%. What would be the arrangement of these genes on a linkage map?
  • Dd
  • 25%
  • 50%
  • DBC
To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who
  • is homozygous recessive for that trait
  • The trait varies along a continuum in the population.
  • heterozygotes... dominant
  • influenced by both genes and the environment
An individual with the blood group genotype LMLN has the phenotype MN. What is the relationship between the LM and LN alleles?
  • gametes have one allele copy for each gene
  • codominance
  • is a carrier
  • carries two copies of the same allele for a gene
In humans, the presence or absence of dimples is a trait controlled by a single gene. What is the genotype of an individual who is heterozygous for dimples?
  • 3%
  • height
  • 0%
  • Dd
A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce
  • height
  • locus
  • Linked
  • hybrid
Linked genes are usually ________
  • the behavior of chromosomes during metaphase I and anaphase I of meiosis
  • alternate versions of a gene
  • located close together on a chromosome
  • is homozygous recessive for that trait
Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?
  • 0%
  • 50%
  • DBC
  • 25%
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Multiple Choice Questions
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