Question 1

The mutation that causes the lighter skin color of all people of European descent was the result of a ____ in the gene for a melanin transport protein.
A) base-pair substitution
B) insertion
C) deletion
D) whole chromosome duplication
E) multiple gene mutations involving several mechanisms

Accepted Answer

The mutation that causes lighter skin color in people of European descent is a base-pair substitution in the gene for a melanin transport protein. This mutation results in less melanin production, which leads to lighter skin color.

Question 2

Genetic recombination as a result of crossing over occurs more readily between genes that are ____.
A) on the sex chromosomes
B) near the centromere
C) located close together on the same chromosome
D) located far apart on the same chromosome
E) located on different chromosomes

Accepted Answer

Genes located far apart on the same chromosome are more likely to undergo genetic recombination as a result of crossing over during meiosis. This is because there is more physical distance between them, increasing the chance of crossovers occurring between them. Genes located close together on the same chromosome may experience little or no recombination during crossing over because they are physically linked and rarely separated. Therefore, choice D is the best answer.

Question 3

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, how many plants would have white flowers and short stems?
A) 1
B) 3
C) 5
D) 9
E) 16

Accepted Answer

The answer of  Purple flower ( A ) is...

Question 4

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( A aBb   ´   AaBb ).
In the figure above, how many plants would have purple flowers and tall stems?
A) 1
B) 3
C) 5
D) 9
E) 16

Accepted Answer

The answer of  Purple flower ( A ) is...

Question 5

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, what would be the genotype of plant #7?
A) AaBb
B) AABb
C) AaBB
D) AABB
E) aaBB

Accepted Answer

The answer of  Purple flower ( A ) is...

Question 6

For this problem, you may want to create a Punnett Square on a separate piece of paper. Manuel has cystic fibrosis, a recessive disorder, and sickle-cell anemia, which is also a recessive disorder. Manuel's partner, Lucretia, is normal for both conditions. What is the probability that Manuel and Lucretia will have a normal child without either of the conditions Manuel has?
A) 0  percent
B) 25  percent
C) 75  percent
D) 100  percent
E) It is not possible to solve this problem with the information provided.

Accepted Answer

The answer of For this problem, you may want to...

Question 7

In cats, short hair L is dominant to long hair l and black hair B is dominant to brown hair b . If you found a black, short-haired cat, you could determine his genotype by crossing it to an animal with a genotype of ____.
A) LLBB
B) llBB
C) llBb
D) llbb
E) LLbb

Accepted Answer

Crossing with a homozygous recessive (llbb) will reveal the genotype of the black, short-haired cat through the offspring's phenotypes.

Question 8

If two individuals who are heterozygous for two traits that display incomplete dominance (e.g., AaBb) mate and have offspring, how many different phenotypes are possible?
A) 1
B) 3
C) 6
D) 9
E) 16

Accepted Answer

In a scenario involving two traits with incomplete dominance, each trait can result in three possible phenotypes (for example, AA, Aa, aa for the first trait and BB, Bb, bb for the second trait). When considering two traits, the combination of these phenotypes can result in 3 x 3 = 9 different phenotypic outcomes.

Question 9

Cystic fibrosis is a recessive disorder. If a couple, each of whom is heterozygous for the CFTR mutation, have children, what is the probability that they will have a child with cystic fibrosis?
A) 0  percent
B) 25  percent
C) 50  percent
D) 75  percent
E) 100  percent

Accepted Answer

Each parent has a 1 in 4 chance of passing on the CFTR mutation to each of their offspring. If both parents pass on the mutation, the child will have cystic fibrosis. Therefore, the probability of having a child with cystic fibrosis is 25 percent or 1 in 4.

Question 10

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, what would be the genotype of plant #9?
A) Aabb
B) aaBb
C) AaBB
D) AABB
E) aaBB

Accepted Answer

The answer of  Purple flower ( A ) is...

Question 11

The ease of detecting and treating ____ is a good example of the advantages of genetic screening.
A) PKU
B) Tay-Sachs
C) Marfan syndrome
D) color blindness
E) Down syndrome

Accepted Answer

Phenylketonuria (PKU) is a genetic disorder that is easily detected through newborn screening. Early detection allows for early treatment, which can prevent severe developmental delays and intellectual disabilities. PKU is a good example of how genetic screening can benefit affected individuals by providing the opportunity for early intervention.

Question 12

The discarded theory of blending inheritance most closely resembles ____.
A) X-linked inheritance
B) dihybridization
C) codominance
D) incomplete dominance
E) complete dominance

Accepted Answer

The discarded theory of blending inheritance suggested that the traits of offspring were a blend of the traits of their parents, which is similar to incomplete dominance where the phenotype of the heterozygote is a blend of the phenotypes of the homozygotes. X-linked inheritance, dihybridization, codominance, and complete dominance do not closely resemble blending inheritance.

Question 13

If a child has an AB blood type, ____.
A) both parents must have different blood types
B) neither parent can have blood type AB
C) both parents must have blood type AB
D) both parents can be any blood type
E) one parent can have blood type O

Accepted Answer

For a child to have an AB blood type, one parent must contribute an A allele and the other a B allele. This means both parents must have different blood types, with at least one parent having either A or AB blood type and the other having either B or AB blood type.

Question 14

In a Punnett square, the letters on top of the square and on the side of the square represent ____.
A) offspring genotypes
B) zygote genotypes
C) parental gametes
D) offspring phenotypes
E) parental phenotypes

Accepted Answer

The letters on top of the square and on the side of the square in a Punnett square represent the parental gametes. These letters represent the possible alleles that can be inherited from each parent and used to determine the genotypes of the offspring.

Question 15

For this problem, you may want to create a Punnett Square on a separate piece of paper. Assume brown eyes are dominant to blue eyes and dimples are dominant to no dimples. John has brown eyes, and his mother has blue eyes. John does not have dimples. Zena has blue eyes and also has no dimples. What are the chances if this couple have children, they will produce a child with blue eyes and no dimples?
A) 0
B) ¼
C) ½
D) ¾
E) There is not enough information provided to solve this problem.

Accepted Answer

The answer of For this problem, you may want to...

Question 16

In codominance, ____.
A) one allele is dominant to another allele
B) the genotype is determined by the phenotype
C) the heterozygous phenotype is intermediate to the homozygous phenotypes
D) the intermediate phenotype may be the result of enzyme insufficiency
E) two alleles may be equally expressed

Accepted Answer

In codominance, both alleles are expressed equally and fully in the heterozygous phenotype. This means that neither allele is dominant over the other, and both contribute to the final phenotype. This is different from incomplete dominance, where the heterozygous phenotype is intermediate to the homozygous phenotypes. The intermediate phenotype in codominance may also be the result of enzyme insufficiency, but this is not a defining characteristic of the trait.

Question 17

Approximately how many gene products are involved in the synthesis of melanin in humans?
A) 10
B) 25
C) 50
D) 100
E) 1000

Accepted Answer

The answer of Approximately how many gene products are involved...

Question 18

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, how many plants would have the genotype AaBb ?
A) 1
B) 3
C) 4
D) 6
E) 9

Accepted Answer

The answer of  Purple flower ( A ) is...

Question 19

In a cross of a DDRR individual with a ddrr individual, the genotype of all offspring will ____.
A) DDRR
B) DdRR
C) DdRr
D) ddRR
E) ddRr

Accepted Answer

When crossing a DDRR individual with a ddrr individual, we know that the Ds will be dominant to the ds, and the Rs will be dominant to the rs. Therefore, all of the offspring will inherit one copy of the D gene from the DDRR parent, and one copy of the d gene from the ddrr parent. Similarly, all of the offspring will inherit one copy of the R gene from the DDRR parent, and one copy of the r gene from the ddrr parent. This results in the genotype DdRr for all offspring.

Question 20

If a pure-breeding wired-hair terrier ( WW ) is crossed with a pure-breeding smooth-hair terrier (ww), and a puppy with a wavy hair is produced, the simplest explanation is ____.
A) a mutation has occurred
B) hair texture is an X-linked trait
C) incomplete dominance
D) hair texture is a lethal trait
E) codominance

Accepted Answer

The production of wavy hair suggests incomplete dominance, where the heterozygous genotype (Ww) results in a blending of the two traits from the homozygous parents (WW and ww). A mutation, X-linked trait, and lethality are not supported by the information given, and codominance would result in a distinct mixture of the two parent traits rather than a blending.

Quiz 10: Patterns of Inheritance

The mutation that causes the lighter skin color of all people of European descent was the result of a ____ in the gene for a melanin transport protein.

Genetic recombination as a result of crossing over occurs more readily between genes that are ____.

Purple flower ( A ) is dominant over white flower ( a ) , and tall stem ( B ) is dominant over short stem ( b ) . The Punnett square represents a cross between two dihybrids ( AaBb ´ AaBb ) . In the figure above, how many plants would have white flowers and short stems?

Purple flower ( A ) is dominant over white flower ( a ) , and tall stem ( B ) is dominant over short stem ( b ) . The Punnett square represents a cross between two dihybrids ( A aBb ´ AaBb ) . In the figure above, how many plants would have purple flowers and tall stems?

Purple flower ( A ) is dominant over white flower ( a ) , and tall stem ( B ) is dominant over short stem ( b ) . The Punnett square represents a cross between two dihybrids ( AaBb ´ AaBb ) . In the figure above, what would be the genotype of plant #7?

In cats, short hair L is dominant to long hair l and black hair B is dominant to brown hair b . If you found a black, short-haired cat, you could determine his genotype by crossing it to an animal with a genotype of ____.

If two individuals who are heterozygous for two traits that display incomplete dominance (e.g., AaBb) mate and have offspring, how many different phenotypes are possible?

Cystic fibrosis is a recessive disorder. If a couple, each of whom is heterozygous for the CFTR mutation, have children, what is the probability that they will have a child with cystic fibrosis?

Purple flower ( A ) is dominant over white flower ( a ) , and tall stem ( B ) is dominant over short stem ( b ) . The Punnett square represents a cross between two dihybrids ( AaBb ´ AaBb ) . In the figure above, what would be the genotype of plant #9?

The ease of detecting and treating ____ is a good example of the advantages of genetic screening.

The discarded theory of blending inheritance most closely resembles ____.

If a child has an AB blood type, ____.

In a Punnett square, the letters on top of the square and on the side of the square represent ____.

In codominance, ____.

Approximately how many gene products are involved in the synthesis of melanin in humans?

Purple flower ( A ) is dominant over white flower ( a ) , and tall stem ( B ) is dominant over short stem ( b ) . The Punnett square represents a cross between two dihybrids ( AaBb ´ AaBb ) . In the figure above, how many plants would have the genotype AaBb ?

In a cross of a DDRR individual with a ddrr individual, the genotype of all offspring will ____.

If a pure-breeding wired-hair terrier ( WW ) is crossed with a pure-breeding smooth-hair terrier (ww) , and a puppy with a wavy hair is produced, the simplest explanation is ____.