Question 1

An allele that is present but unexpressed is
A)codominant.
B)dominant.
C)pleiotropic.
D)epistatic.
E)recessive.

Accepted Answer

An allele that is present but unexpressed is known as a recessive allele. This means that even though an individual may have both a dominant and recessive allele for a particular trait, only the dominant allele will be expressed. The recessive allele will be hidden, but can be passed on to future generations, potentially leading to the expression of the trait in future offspring.

Question 2

The Principle of ________ states that the 2 alleles present at each gene locus separate from one another during gamete formation and remain distinct.
A)Alleles
B)Segregation
C)Crossing over
D)Dominance
E)Independent assortment

Accepted Answer

The principle of segregation, also known as Mendel's first law, states that during gamete formation, the two alleles at a gene locus separate from each other so that each gamete receives only one allele. This ensures that each offspring inherits one allele from each parent, contributing to genetic diversity.

Question 3

Mendel chose the garden pea for his work on inheritance for which of the following reasons? Check all that apply.
A)Some traits in pea plants are controlled by one dominant allele and one recessive allele.
B)Earlier investigators had shown segregation among the offspring.
C)A large number of true breeding varieties were available.
D)The generation time was short; many offspring can be grown easily.
E)He could choose to self- or cross-pollinate.

Accepted Answer

B,C,D,E

Question 4

In modern terminology,Mendel's heredity "factors" are called
A)DNA.
B)chromosomes.
C)genes.
D)RNA.

Accepted Answer

In modern terminology, Mendel's heredity "factors" are called genes. Genes are specific sequences of DNA that carry genetic information from one generation to the next. Chromosomes are structures made of DNA and proteins that contain genes, but they are not synonymous with genes. RNA is another type of nucleic acid that plays various roles in the expression of genetic information, but it is not the same as genes. Therefore, the best choice is C) genes.

Question 5

In a heterozygous individual,the allele being expressed is
A)recessive.
B)codominant.
C)pleiotropic.
D)dominant.
E)epistatic.

Accepted Answer

In a heterozygous individual, the dominant allele is expressed while the recessive allele is not. Therefore, the allele being expressed is dominant.

Question 6

During his experiments with pea plants,Mendel referred to the trait that was expressed in the F₁ or first filial generation as A)recessive. B)dominant. C)codominant. D)independent. E)homozygous.

Accepted Answer

In the F1 generation, Mendel observed that only one of the parental traits was expressed, indicating that one allele was dominant over the other. Therefore, the trait expressed was referred to as dominant, making choice B the correct answer.

Question 7

Mendel used the garden ________ plant for his studies on inheritance.
A)lily
B)carrot
C)onion
D)pea

Accepted Answer

Mendel used pea plants for his studies on inheritance because they have several easily observable traits (such as seed color and shape, flower color and position, pod shape and color, etc.) that are determined by only one or a few genes. This made it easier for him to track the inheritance patterns of these traits across generations of plants.

Question 8

In Mendel's experiments on seed color in pea plants,when a dominant yellow seed-bearing plant was crossed with a recessive green seed-bearing plant,what was the approximate phenotypic ratio among the F₂ generation? A)1 yellow: 3 green B)1 yellow: 1 green C)3 yellow: 1 green D)all yellow E)9:3:3:1

Accepted Answer

When a dominant yellow seed-bearing plant (YY) is crossed with a recessive green seed-bearing plant (yy), the F1 generation will all be heterozygous yellow seed-bearing plants (Yy). When the F1 generation plants are crossed, the possible genotypic ratios are YY:Yy:yy in a 1:2:1 ratio, and the phenotypic ratio is 3 yellow:1 green. Therefore, the approximate phenotypic ratio among the F2 generation would be 3 yellow:1 green.

Question 9

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas.When he crossed two true-breeding varieties,he found all of the following: Check all that apply. A)All the F₁ offspring had the dominant trait. B)If both parents have the same trait,then all of their offspring will also have that trait. C)Some F₂ offspring had the dominant trait and some had the recessive trait. D)Among the F₂offspring,more had the dominant trait and fewer had the recessive trait.

Accepted Answer

Knight's experiments showed that all F1 offspring exhibited the dominant trait. In the F2 generation, both dominant and recessive traits appeared, with more offspring showing the dominant trait.

Question 10

Mendel's understanding of the inheritance of traits in peas,expressed in modern language,included: Check all that apply.
A)parents transmit information encoded in genes.
B)each individual contains two genes for each trait.
C)not all genes are identical; alternative forms (alleles)exist.
D)each of the alleles present in an individual is discrete.
E)if a given allele is present,its effects will be seen in the individual.

Accepted Answer

EMendel's work, when translated into modern genetic terms, shows that parents pass on discrete units of inheritance (genes) (A), each individual carries two copies of genes for each trait, one from each parent (B), there are different versions of genes known as alleles (C), and each allele maintains its discrete nature within an individual (D). However, not all alleles are dominant; some are recessive, meaning the presence of an allele does not guarantee its expression in the individual's phenotype (E), which contradicts the statement in option E.

Question 11

Mendel demonstrated which of the following about inherited traits? Check all that apply.
A)traits can be hidden in some generations,but subsequently reappear unchanged in future generations.
B)traits segregate among the offspring of a cross.
C)certain traits are more likely to appear than their alternatives.
D)some traits show blending inheritance.
E)parents that both have the same trait can have offspring with an alternative trait.

Accepted Answer

Mendel's work demonstrated that traits can skip generations and reappear unchanged (A), which is a result of recessive genes being masked by dominant ones in one generation and then reappearing when two recessive alleles come together. He also found that traits segregate independently among offspring (B), meaning each offspring receives a combination of alleles from their parents. Mendel's laws of inheritance include the principle of dominance (C), where dominant alleles mask the effects of recessive alleles, leading to certain traits being more likely to appear. Finally, Mendel's experiments showed that even when both parents exhibit a certain trait, they can produce offspring with an alternative trait (E), which happens if both parents carry a recessive allele for the alternative trait. Mendel's work did not support the concept of blending inheritance (D), where traits from two parents blend together to form intermediate traits in their offspring; instead, his work laid the foundation for the particulate theory of inheritance, where traits are inherited as discrete units (genes).

Question 12

A diploid organism that has two identical alleles for a given trait is called ________ for that trait.
A)homozygous
B)heterozygous
C)dominant
D)recessive
E)codominant

Accepted Answer

Homozygous refers to an organism having two identical alleles for a given trait. This means that both alleles are either dominant or recessive. Heterozygous means having two different alleles for a given trait. Dominant and recessive refer to the expression of a trait in the presence of multiple alleles, and codominant refers to two alleles that are both expressed equally in the phenotype of the organism.

Question 13

Alternate forms of the same gene are called
A)homologues.
B)genotypes.
C)cofactors.
D)alleles.

Accepted Answer

Alternate forms of the same gene are called alleles. Homologues are pairs of chromosomes with corresponding gene loci. Genotypes refer to the genetic makeup of an individual. Cofactors are non-protein molecules that assist in enzyme activity.

Question 14

The observable expression of the genes present in an organism is called its
A)phenotype.
B)genotype.
C)pedigree.
D)karyotype.

Accepted Answer

Phenotype refers to the physical and observable characteristics of an organism, which are determined by its genetic makeup (genotype) as well as environmental factors. Pedigree and karyotype both refer to specific types of genetic analysis and are not synonymous with the overall expression of an organism's genes.

Question 15

The first detailed and quantitative studies on inheritance were carried out by an Austrian monk named ________.
A)Mendel
B)Darwin
C)Mendeleev
D)Benedict

Accepted Answer

The first detailed and quantitative studies on inheritance were carried out by an Austrian monk named Gregor Mendel.

Question 16

The phenotypic ratio for the F₁generation that results from a testcross between a homozygous recessive individual and a heterozygous individual is A)1:1 B)2:1 C)3:1 D)1:2:1

Accepted Answer

In a testcross between a homozygous recessive individual and a heterozygous individual, the offspring will exhibit a 1:1 phenotypic ratio. This is because the homozygous recessive parent can only contribute recessive alleles, while the heterozygous parent can contribute either a dominant or a recessive allele, resulting in half of the offspring expressing the dominant phenotype and half expressing the recessive phenotype.

Question 17

Individuals that have 2 alleles for most gene loci are best described as
A)haploid.
B)diploid.
C)dihybrid.
D)homozygous.
E)heterozygous.

Accepted Answer

Individuals that have 2 alleles for most gene loci are diploid. This means they have two sets of chromosomes, one from each parent.

Question 18

Mendel used the ________ to determine whether an individual with the dominant phenotype was homozygous or heterozygous for that trait. A)backcross B)testcross C)dihybrid cross D)F₂ generation E)double cross

Accepted Answer

Mendel used the testcross to determine whether an individual with the dominant phenotype was homozygous or heterozygous for that trait. This involved crossing the individual with a homozygous recessive individual and observing the phenotypes of the offspring. If any offspring showed the recessive phenotype, it meant that the individual with the dominant phenotype was heterozygous. If all offspring showed the dominant phenotype, it meant that the individual with the dominant phenotype was homozygous.

Question 19

An allele for a particular trait that is only expressed in the presence of a second copy of the same allele is called
A)dominant.
B)codominant.
C)incompletely dominant.
D)recessive.
E)pleiotropic.

Accepted Answer

This describes the definition of a recessive allele, which must be present in two copies to be expressed in an individual's phenotype.

Question 20

If fertilization involves two gametes that contain different alleles of a given gene,the resulting offspring is
A)dihybrid.
B)haploid.
C)heterozygous.
D)homozygous.
E)polygenic.

Accepted Answer

If two gametes contain different alleles of a given gene, the resulting offspring will be heterozygous for that gene, meaning they have two different alleles (versions) of the gene. Therefore, option C is the correct answer. Dihybrid refers to the inheritance of two different traits, haploid refers to a cell with a single set of chromosomes, and polygenic refers to traits that are controlled by multiple genes.

Quiz 12: Patterns of Inheritance

An allele that is present but unexpressed is

The Principle of ________ states that the 2 alleles present at each gene locus separate from one another during gamete formation and remain distinct.

Mendel chose the garden pea for his work on inheritance for which of the following reasons? Check all that apply.

In modern terminology,Mendel's heredity "factors" are called

In a heterozygous individual,the allele being expressed is

During his experiments with pea plants,Mendel referred to the trait that was expressed in the F1 or first filial generation as

Mendel used the garden ________ plant for his studies on inheritance.

In Mendel's experiments on seed color in pea plants,when a dominant yellow seed-bearing plant was crossed with a recessive green seed-bearing plant,what was the approximate phenotypic ratio among the F2 generation?

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas.When he crossed two true-breeding varieties,he found all of the following: Check all that apply.

Mendel's understanding of the inheritance of traits in peas,expressed in modern language,included: Check all that apply.

Mendel demonstrated which of the following about inherited traits? Check all that apply.

A diploid organism that has two identical alleles for a given trait is called ________ for that trait.

Alternate forms of the same gene are called

The observable expression of the genes present in an organism is called its

The first detailed and quantitative studies on inheritance were carried out by an Austrian monk named ________.

The phenotypic ratio for the F1 generation that results from a testcross between a homozygous recessive individual and a heterozygous individual is

Individuals that have 2 alleles for most gene loci are best described as

Mendel used the ________ to determine whether an individual with the dominant phenotype was homozygous or heterozygous for that trait.

An allele for a particular trait that is only expressed in the presence of a second copy of the same allele is called

If fertilization involves two gametes that contain different alleles of a given gene,the resulting offspring is

During his experiments with pea plants,Mendel referred to the trait that was expressed in the F₁ or first filial generation as

In Mendel's experiments on seed color in pea plants,when a dominant yellow seed-bearing plant was crossed with a recessive green seed-bearing plant,what was the approximate phenotypic ratio among the F₂ generation?

The phenotypic ratio for the F₁generation that results from a testcross between a homozygous recessive individual and a heterozygous individual is