Question 1

A true-breeding strain of tall soybean plants is crossed with a true-breeding strain of short soybean plants.All the offspring are short.Thus, tall is a _______ trait.

Accepted Answer

The fact that all the offspring are short indicates that the trait for shortness is dominant over the trait for tallness. This makes tallness a recessive trait.

Question 2

Compare the closely related concepts of penetrance and expressivity.

Accepted Answer

The answer of Compare the closely related concepts of penetrance...

Question 3

Different forms of a gene are referred to as

Accepted Answer

Different forms of a gene are called alleles. Traits refer to observable characteristics, phenotypes refer to the physical expression of genetic traits, genotypes refer to the genetic makeup of an individual, and genomes refer to the entire set of genetic material in an organism.

Question 4

Refer to the figure showing a pedigree.  What is the probability that individual A will pass on the trait to her offspring?

Accepted Answer

The answer of Refer to the figure showing a pedigree....

Question 5

Due to the phenomenon of dominance,

Accepted Answer

Dominance refers to the expression of one allele over another in a heterozygous individual. This means that even though an individual may have different genotypes (heterozygous or homozygous), the dominant allele will always be expressed in the phenotype. Therefore, different genotypes can result in the same phenotype. For example, a heterozygous individual (Tt) and a homozygous dominant individual (TT) will both have the same phenotype (tall), even though their genotypes are different.

Question 6

What is the genetic significance of a hemizygous gene?

Accepted Answer

The answer of What is the genetic significance of a...

Question 7

Refer to the figure showing a pedigree of a sex-linked recessive trait.Note here that only individuals that are affected are shaded; unshaded individuals may or may not be carriers.  Consider the affected son of female number 5.If his wife does not carry the allele, the probability that his first son will be affected with the trait is _______ percent.

Accepted Answer

The answer of Refer to the figure showing a pedigree...

Question 8

Refer to the figure showing a pedigree.  What is the most likely mode of genetic transmission?

Accepted Answer

The answer of Refer to the figure showing a pedigree....

Question 9

The theory of _______ inheritance proposes that the units of hereditary determinants remain stable and are not lost, across generations.

Accepted Answer

The theory of particulate inheritance, also known as Mendelian inheritance, proposes that hereditary determinants come in discrete units (now known as genes) and remain stable across generations. This theory is based on the work of Gregor Mendel and is the foundation of modern genetics. The other choices do not accurately describe this theory.

Question 10

A dihybrid cross for unlinked genes

Accepted Answer

A dihybrid cross for unlinked genes involves crossing individuals who are heterozygous for two different traits that are on different chromosomes. These individuals can be considered identical double heterozygotes. The resulting offspring will show a 9:3:3:1 phenotypic ratio and a 1:2:1:2:4:2:1:2:1 genotypic ratio. There is no basis for any of the other answer choices.

Question 11

Draw a pedigree for three generations in which the grandfather has red-green color blindness and his daughter is a carrier.

Accepted Answer

The answer of Draw a pedigree for three generations in...

Question 12

Draw a pedigree for at least three generations and 12 individuals that shows the transmission of a dominant X-linked trait.

Accepted Answer

The answer of Draw a pedigree for at least three...

Question 13

True-breeding dark mice are crossed with true-breeding light mice.The resulting progeny are then crossed with one another.This is an example of a _______ cross.

Accepted Answer

The cross between true-breeding dark and light mice is a monohybrid cross because it involves the inheritance of only one trait (fur color). The resulting progeny from this cross are heterozygous for the fur color trait, and crossing them with each other is a test cross.

Question 14

Cytoplasmic traits in certain species of trees are passed from the male plant to all of its progeny.Compare this observation to cytoplasmic inheritance in humans.

Accepted Answer

The answer of Cytoplasmic traits in certain species of trees...

Question 15

Many antibiotic resistance genes are located on plasmids.Antibiotics are routinely given to livestock by many farmers to improve productivity and prevent illness.Why are many individuals concerned about this practice as it relates to human health?

Accepted Answer

The answer of Many antibiotic resistance genes are located on...

Question 16

A particular genetic cross in which an individual with a dominant phenotype and an unknown genotype is crossed with an individual known to be homozygous for a recessive trait is referred to as

Accepted Answer

A test cross is a genetic cross between an individual with a dominant phenotype, but an unknown genotype, and an individual who is homozygous recessive for the trait of interest. The purpose of the test cross is to determine the unknown genotype of the parent with the dominant phenotype. This cross can be used to determine whether the dominant individual is homozygous dominant (DD) or heterozygous (Dd) for the trait in question. Dihybrid cross involves two traits, reciprocal cross is a type of cross in which the sexes of the parents are switched, and filial generation mating refers to breeding between two of the offspring from the same parental cross.

Question 17

A dog has floppy ears.The nature of the ear is a _______, and the floppy nature of this particular dog's ears is the _______.

Accepted Answer

The nature of the ear is a character, and the floppy nature of this particular dog's ears is a trait because it is a specific observable feature of the character. Genotype refers to the genetic makeup, which is not directly observable, so it is not the best choice here.

Question 18

In cats, black coat (B) is codominant with yellow (b).The coat color gene is on the X chromosome.Calico cats, which have coats with black and yellow patches, are heterozygous for the coat color alleles.Why are most calico cats females?

Accepted Answer

The answer of In cats, black coat (B) is codominant...

Question 19

In pea plants, the allele R produces a red flower and is dominant to the white allele (r).A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, whereas the other half have white flowers.Therefore, the genotype of the test-crossed parent was

Accepted Answer

The test cross results (half red, half white offspring) indicate that the red-flowered parent must be heterozygous (Rr) to produce both red (Rr) and white (rr) offspring when crossed with a white (rr) parent.

Question 20

Refer to the figure showing a pedigree.  What is the probability that individual B will pass on the trait to his offspring?

Accepted Answer

The answer of Refer to the figure showing a pedigree....

Quiz 12: Inheritance, Genes, and Chromosomes

A true-breeding strain of tall soybean plants is crossed with a true-breeding strain of short soybean plants.All the offspring are short.Thus, tall is a _______ trait.

Compare the closely related concepts of penetrance and expressivity.

Different forms of a gene are referred to as

Refer to the figure showing a pedigree. What is the probability that individual A will pass on the trait to her offspring?

Due to the phenomenon of dominance,

What is the genetic significance of a hemizygous gene?

Refer to the figure showing a pedigree. What is the most likely mode of genetic transmission?

The theory of _______ inheritance proposes that the units of hereditary determinants remain stable and are not lost, across generations.

A dihybrid cross for unlinked genes

Draw a pedigree for three generations in which the grandfather has red-green color blindness and his daughter is a carrier.

Draw a pedigree for at least three generations and 12 individuals that shows the transmission of a dominant X-linked trait.

True-breeding dark mice are crossed with true-breeding light mice.The resulting progeny are then crossed with one another.This is an example of a _______ cross.

Cytoplasmic traits in certain species of trees are passed from the male plant to all of its progeny.Compare this observation to cytoplasmic inheritance in humans.

Many antibiotic resistance genes are located on plasmids.Antibiotics are routinely given to livestock by many farmers to improve productivity and prevent illness.Why are many individuals concerned about this practice as it relates to human health?

A particular genetic cross in which an individual with a dominant phenotype and an unknown genotype is crossed with an individual known to be homozygous for a recessive trait is referred to as

A dog has floppy ears.The nature of the ear is a _, and the floppy nature of this particular dog's ears is the _.

In cats, black coat (B) is codominant with yellow (b).The coat color gene is on the X chromosome.Calico cats, which have coats with black and yellow patches, are heterozygous for the coat color alleles.Why are most calico cats females?

In pea plants, the allele R produces a red flower and is dominant to the white allele (r) .A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, whereas the other half have white flowers.Therefore, the genotype of the test-crossed parent was

Refer to the figure showing a pedigree. What is the probability that individual B will pass on the trait to his offspring?