Biology 111 Exam 2 Questions with Correct
Answers
Hemophilia is a genetic disease that has plagued the royal houses of Europe since the
time of Queen Victoria, who was a carrier. Her granddaughter, Alexandra, married
Nicholas II, the last czar of imperial Russia. Alexandra was a carrier for hemophilia,
but Nicholas was normal. Their son, Alexis, was afflicted with the disease. Based on this
scenario, it is most likely that
each of the sisters had a 50% chance of being a carrier of the gene.
A child is born with dwarfism ( tt). His parents are of normal height. Which of the
following must be TRUE of the parents?
They are both heterozygous tall.
In Mendel's experiments, if the gene for tall ( T 1) plants was incompletely dominant
over the gene for short ( T 2) plants, what would be the result of crossing two T 1 T 2
plants?
25% tall, 50% intermediate, and 25% short
Imagine that you self-pollinate heterozygous purple-flowered, long-pollened pea plants
and get mostly purple-flowered, long-pollened plants and white-flowered, short-
pollened plants, with a few purple-flowered, short-pollened or white-flowered, long-
pollened plants. What is the most likely explanation?
The genes for flower color and pollen length are linked.
Blood typing is often used as evidence in paternity cases in court. In one case, the
mother had blood type B and the child had blood type O. Which of the following blood
types could the father NOT have?
, AB
According to the law of segregation
pairs of alleles on homologous chromosomes separate during the formation of gametes.
Which of the following is the most common chromosome disorder among live-born
infants?
Down syndrome
Mendel's law of segregation states that
members of a pair of alleles on homologous chromosomes move away from each other
during gamete formation.
A disorder caused by nondisjunction of chromosome 21, resulting in a trisomy 21 child,
is
Down syndrome
According to the law of segregation, in an organism with the genotype Aa
one-half of the gametes get the A allele and one-half get the a allele.
Peas were a good organism of choice for Mendel because
he could study one trait at a time.
A Mendelian test cross is used to determine whether
an individual is homozygous or heterozygous.
All of the following are true regarding pedigree analysis EXCEPT that it
is exclusively used to study the patterns of inheritance in dogs.
Answers
Hemophilia is a genetic disease that has plagued the royal houses of Europe since the
time of Queen Victoria, who was a carrier. Her granddaughter, Alexandra, married
Nicholas II, the last czar of imperial Russia. Alexandra was a carrier for hemophilia,
but Nicholas was normal. Their son, Alexis, was afflicted with the disease. Based on this
scenario, it is most likely that
each of the sisters had a 50% chance of being a carrier of the gene.
A child is born with dwarfism ( tt). His parents are of normal height. Which of the
following must be TRUE of the parents?
They are both heterozygous tall.
In Mendel's experiments, if the gene for tall ( T 1) plants was incompletely dominant
over the gene for short ( T 2) plants, what would be the result of crossing two T 1 T 2
plants?
25% tall, 50% intermediate, and 25% short
Imagine that you self-pollinate heterozygous purple-flowered, long-pollened pea plants
and get mostly purple-flowered, long-pollened plants and white-flowered, short-
pollened plants, with a few purple-flowered, short-pollened or white-flowered, long-
pollened plants. What is the most likely explanation?
The genes for flower color and pollen length are linked.
Blood typing is often used as evidence in paternity cases in court. In one case, the
mother had blood type B and the child had blood type O. Which of the following blood
types could the father NOT have?
, AB
According to the law of segregation
pairs of alleles on homologous chromosomes separate during the formation of gametes.
Which of the following is the most common chromosome disorder among live-born
infants?
Down syndrome
Mendel's law of segregation states that
members of a pair of alleles on homologous chromosomes move away from each other
during gamete formation.
A disorder caused by nondisjunction of chromosome 21, resulting in a trisomy 21 child,
is
Down syndrome
According to the law of segregation, in an organism with the genotype Aa
one-half of the gametes get the A allele and one-half get the a allele.
Peas were a good organism of choice for Mendel because
he could study one trait at a time.
A Mendelian test cross is used to determine whether
an individual is homozygous or heterozygous.
All of the following are true regarding pedigree analysis EXCEPT that it
is exclusively used to study the patterns of inheritance in dogs.
