BIOL 4003 Exam 1 questions with
complete solutions
Quiz 1: Let's suppose that true-breeding pea plants with purple flowers and yellow seeds were
crossed to true-breeding plants with white flowers and green seeds. The F1 plants had purple
flowers that produced yellow seeds. The genes that affect these traits independently assort. If
the F1 plants were allowed to self-fertilize, the expected ratio of the F2 generation would be:
3 purple flowers/yellow seeds : 1 white flowers/green seeds
9 purple flowers/yellow seeds: 3 white flowers/yellow seeds : 3 purple flowers/green seeds : 1
white flowers/green seeds
9 white flowers/yellow seeds : 3 purple flowers/yellow seeds : 3 white flowers/green seeds : 1
purple flowers/green seeds
1 white flowers/yellow seeds : 1 purple flowers/yellow seeds : 1 white flowers/green seeds : 1
purple flowers/green seeds - correct answer ✔✔ 9 purple flowers/yellow seeds: 3 white
flowers/yellow seeds : 3 purple flowers/green seeds : 1 white flowers/green seeds
Quiz 1: Which of the following statements is false?
An allele is a gene.
A true-breeding individual is homozygous.
A heterozygote has different alleles for a given gene.
,For most species, a chromosome carries a single gene. - correct answer ✔✔ For most species, a
chromosome carries a single gene.
Quiz 1:
In humans, let's suppose an individual has a diploid set of autosomes and is XXY with regard to
their sex chromosomes. This person would be ____________ because ___________.
male, they have a Y chromosome.
female, they have two X
chromosomes.
female, the ratio of X
chromosomes to autosomes is 1.0
male, because they have a diploid set of autosomes - correct answer ✔✔ male, they have a Y
chromosome.
Quiz 1: The pedigree below involves a genetic disease in humans. Affected individuals are
shown in black.
Autosomal dominant only
Autosomal recessive only
, X-linked recessive only
Autosomal dominant and autosomal recessive - correct answer ✔✔ Autosomal dominant only
Quiz 1 If a rare dominant allele exerts its effect by antagonizing (inhibiting) the function of the
wild-type (normal) protein, this phenomenon is called
haploinsufficiency.
a gain-of-function mutation.
a dominant negative mutation.
overdominance. - correct answer ✔✔ a dominant negative mutation.
Quiz 1: Flower color in the four o'clock plant exhibits incomplete dominance. A red-flowered
plant was crossed to white-flowered plant to obtain F1 plants. The F1 plants were then crossed
to white-flowered plants to produce an F2 generation. The expected ratio for the F2 plants
would be:
1 red-flowered : 2 pink : 1 white-flowered
1 red-flowered : 1 white flowered
1 pink-flowered : 1 white flowered
All pink flowered - correct answer ✔✔ 1 pink-flowered : 1 white flowered
complete solutions
Quiz 1: Let's suppose that true-breeding pea plants with purple flowers and yellow seeds were
crossed to true-breeding plants with white flowers and green seeds. The F1 plants had purple
flowers that produced yellow seeds. The genes that affect these traits independently assort. If
the F1 plants were allowed to self-fertilize, the expected ratio of the F2 generation would be:
3 purple flowers/yellow seeds : 1 white flowers/green seeds
9 purple flowers/yellow seeds: 3 white flowers/yellow seeds : 3 purple flowers/green seeds : 1
white flowers/green seeds
9 white flowers/yellow seeds : 3 purple flowers/yellow seeds : 3 white flowers/green seeds : 1
purple flowers/green seeds
1 white flowers/yellow seeds : 1 purple flowers/yellow seeds : 1 white flowers/green seeds : 1
purple flowers/green seeds - correct answer ✔✔ 9 purple flowers/yellow seeds: 3 white
flowers/yellow seeds : 3 purple flowers/green seeds : 1 white flowers/green seeds
Quiz 1: Which of the following statements is false?
An allele is a gene.
A true-breeding individual is homozygous.
A heterozygote has different alleles for a given gene.
,For most species, a chromosome carries a single gene. - correct answer ✔✔ For most species, a
chromosome carries a single gene.
Quiz 1:
In humans, let's suppose an individual has a diploid set of autosomes and is XXY with regard to
their sex chromosomes. This person would be ____________ because ___________.
male, they have a Y chromosome.
female, they have two X
chromosomes.
female, the ratio of X
chromosomes to autosomes is 1.0
male, because they have a diploid set of autosomes - correct answer ✔✔ male, they have a Y
chromosome.
Quiz 1: The pedigree below involves a genetic disease in humans. Affected individuals are
shown in black.
Autosomal dominant only
Autosomal recessive only
, X-linked recessive only
Autosomal dominant and autosomal recessive - correct answer ✔✔ Autosomal dominant only
Quiz 1 If a rare dominant allele exerts its effect by antagonizing (inhibiting) the function of the
wild-type (normal) protein, this phenomenon is called
haploinsufficiency.
a gain-of-function mutation.
a dominant negative mutation.
overdominance. - correct answer ✔✔ a dominant negative mutation.
Quiz 1: Flower color in the four o'clock plant exhibits incomplete dominance. A red-flowered
plant was crossed to white-flowered plant to obtain F1 plants. The F1 plants were then crossed
to white-flowered plants to produce an F2 generation. The expected ratio for the F2 plants
would be:
1 red-flowered : 2 pink : 1 white-flowered
1 red-flowered : 1 white flowered
1 pink-flowered : 1 white flowered
All pink flowered - correct answer ✔✔ 1 pink-flowered : 1 white flowered
