Biology 1408: Exam 3 Practice
Questions
A thoroughbred racehorse could have at most _ alleles of the same gene for a Mendelian trait. - Answer-
2
When comparing a human sperm cell to a skin cell from the same individuals, what differences would be
expected? - Answer-The sperm cell would contain only one allele for a given gene; the skin cell would
contain two alleles.
The coat color in a Siamese cat is determined by a temperature-sensitive allele that allows the pigment
melanin to be produced extremities of the body. What might explain this phenomenon? - Answer-Alleles
produce proteins that function best in specific temperature ranges.
A hammer is needed to pound nails into a board. Even if one has the nails, they cannot be used without
first procuring a hammer. This is similar to the genetic relationship known as - Answer-epistasis.
One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU
is the result of a mutation in a single gene that leads to mental retardation and a host of other
phenotypes including eczema and a "musty" smell. By detecting PKU early, doctors are able to reduce
the effects of this condition with a modified diet extremely low in the amino acid phenylalanine. PKU is
an example of - Answer-pleiotropy.
A chestnut (red-colored) horse is mated with a cremello (cream-colored) horse. Over a 10-year period all
their offspring are palomino (gold-colored). This pattern of inheritance is best explained by - Answer-
incomplete dominance.
, Which of the following represents all possible gametes that can be formed by an individual with the
genetic makeup FfGgHH? - Answer-FGH, FgH, fGH, fgH
In a particular plant, two genes control leaf shape and fruit color. Round leaves (R ) are dominant to
jagged leaves (r ). Yellow fruits (Y) are dominant to white fruits (y). A true-breeding round-leaved,
yellow-fruited plant is mated with a true-breeding jagged-leaved, white-fruited plant. What are the
genotypes of plants involved in this cross? - Answer-RRYY?0xrryy
Suppose D were dominant and d were recessive, and you could label the D allele in the P generation
with a radioactive substance that could be inherited over several generations. You create hybrids by
mating your radioactive DD individuals to dd individuals. Next, you cross two F1 individuals (with the Dd
genotype). Among the 1,000 F2 offspring, how many would you predict would be radioactive? - Answer-
750
In the Punnett square shown below, the lettered circles on the top and left of the square (indicated by
the arrows) represent the - Answer-gametes that may be produced by each parent involved in the cross.
A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a
specific gamete contains the recessive allele for flower color? - Answer-50 percent
The 9:3:3:1 ration of phenotypes that occurs in the F2 generation of the cross shown below can be
explained using - Answer-both the laws of segregation and independent assortment.
When Mendel proposed the law of segregation, which of the following pieces of information did he NOT
have? - Answer-knowledge of the location of the alleles for flower color
Mutations will affect the - Answer-genotype, which may affect the phenotype
Why did Mendel analyze thousands of plants while conducting his research? - Answer-The likelihood of
seeing a clear numerical pattern is higher with a larger data set.
Questions
A thoroughbred racehorse could have at most _ alleles of the same gene for a Mendelian trait. - Answer-
2
When comparing a human sperm cell to a skin cell from the same individuals, what differences would be
expected? - Answer-The sperm cell would contain only one allele for a given gene; the skin cell would
contain two alleles.
The coat color in a Siamese cat is determined by a temperature-sensitive allele that allows the pigment
melanin to be produced extremities of the body. What might explain this phenomenon? - Answer-Alleles
produce proteins that function best in specific temperature ranges.
A hammer is needed to pound nails into a board. Even if one has the nails, they cannot be used without
first procuring a hammer. This is similar to the genetic relationship known as - Answer-epistasis.
One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU
is the result of a mutation in a single gene that leads to mental retardation and a host of other
phenotypes including eczema and a "musty" smell. By detecting PKU early, doctors are able to reduce
the effects of this condition with a modified diet extremely low in the amino acid phenylalanine. PKU is
an example of - Answer-pleiotropy.
A chestnut (red-colored) horse is mated with a cremello (cream-colored) horse. Over a 10-year period all
their offspring are palomino (gold-colored). This pattern of inheritance is best explained by - Answer-
incomplete dominance.
, Which of the following represents all possible gametes that can be formed by an individual with the
genetic makeup FfGgHH? - Answer-FGH, FgH, fGH, fgH
In a particular plant, two genes control leaf shape and fruit color. Round leaves (R ) are dominant to
jagged leaves (r ). Yellow fruits (Y) are dominant to white fruits (y). A true-breeding round-leaved,
yellow-fruited plant is mated with a true-breeding jagged-leaved, white-fruited plant. What are the
genotypes of plants involved in this cross? - Answer-RRYY?0xrryy
Suppose D were dominant and d were recessive, and you could label the D allele in the P generation
with a radioactive substance that could be inherited over several generations. You create hybrids by
mating your radioactive DD individuals to dd individuals. Next, you cross two F1 individuals (with the Dd
genotype). Among the 1,000 F2 offspring, how many would you predict would be radioactive? - Answer-
750
In the Punnett square shown below, the lettered circles on the top and left of the square (indicated by
the arrows) represent the - Answer-gametes that may be produced by each parent involved in the cross.
A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a
specific gamete contains the recessive allele for flower color? - Answer-50 percent
The 9:3:3:1 ration of phenotypes that occurs in the F2 generation of the cross shown below can be
explained using - Answer-both the laws of segregation and independent assortment.
When Mendel proposed the law of segregation, which of the following pieces of information did he NOT
have? - Answer-knowledge of the location of the alleles for flower color
Mutations will affect the - Answer-genotype, which may affect the phenotype
Why did Mendel analyze thousands of plants while conducting his research? - Answer-The likelihood of
seeing a clear numerical pattern is higher with a larger data set.
