Question 1

Which of the following statements is correct in describing the terms monohybrid cross and dihybrid cross?

Accepted Answer

A)  A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. 
B)  A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied. 
C)  A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. 
D)  A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio. 
A)  A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. 
B)  A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied. 
C)  A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. 
D)  A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio.

Question 2

What is the probability of producing the genotype AABBCC in a cross of individuals who both possess this genotype: AaBbCc?

Accepted Answer

A)  1/4 
B)  1/8 
C)  1/16 
D)  1/64 
A)  1/4 
B)  1/8 
C)  1/16 
D)  1/64

Question 3

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

Accepted Answer

A)  4 
B)  8 
C)  16 
D)  64 
A)  4 
B)  8 
C)  16 
D)  64

Question 4

Use the figure and the following description to answer the question.
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F₁ offspring is allowed to self-pollinate. The predicted outcome of the F₂ is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.
 
Which of the boxes marked 1-4 correspond to plants with dark leaves?

Accepted Answer

A)  1 only 
B)  2 and 3 
C)  4 only 
D)  1, 2, and 3 
A)  1 only 
B)  2 and 3 
C)  4 only 
D)  1, 2, and 3

Question 5

Which of the following scenarios describes an example of epistasis?

Accepted Answer

A)  Recessive genotypes for each of two genes (aabb) results in an albino corn snake. 
B)  In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing. 
C)  In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combination of other genes. 
D)  In cacti, there are several genes for the type of spines. 
A)  Recessive genotypes for each of two genes (aabb) results in an albino corn snake. 
B)  In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing. 
C)  In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combination of other genes. 
D)  In cacti, there are several genes for the type of spines.

Question 6

Mendel's law of independent assortment has its basis in which of the following events of meiosis I?

Accepted Answer

A)  synapsis of homologous chromosomes 
B)  crossing over of homologous pairs of chromosomes 
C)  alignment of pairs of homologous chromosomes along the middle of the cell 
D)  the division of cells at telophase 
A)  synapsis of homologous chromosomes 
B)  crossing over of homologous pairs of chromosomes 
C)  alignment of pairs of homologous chromosomes along the middle of the cell 
D)  the division of cells at telophase

Question 7

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce ________.

Accepted Answer

A)  all sharp-spined progeny 
B)  50% sharp-spined, 50% dull-spined progeny 
C)  25% sharp-spined, 50% dull-spined, 25% spineless progeny 
D)  It is impossible to determine the phenotypes of the progeny. 
A)  all sharp-spined progeny 
B)  50% sharp-spined, 50% dull-spined progeny 
C)  25% sharp-spined, 50% dull-spined, 25% spineless progeny 
D)  It is impossible to determine the phenotypes of the progeny.

Question 8

Given the following genotypes for two parents, AABBCc × AabbCc, assume that all traits exhibit simple dominance and independent assortment. What proportion of the progeny of this cross will be expected to phenotypically resemble the first parent with the genotype AABBCc?

Accepted Answer

A)  1/4 
B)  3/4 
C)  3/8 
D)  1 
A)  1/4 
B)  3/4 
C)  3/8 
D)  1

Question 9

A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have the normal number of digits (five fingers on each hand and five toes on each foot.) Having extra digits is a dominant trait. The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits?

Accepted Answer

A)  1/2 
B)  1/16 
C)  1/8 
D)  3/4 
A)  1/2 
B)  1/16 
C)  1/8 
D)  3/4

Question 10

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers, and the other has white, terminal flowers; all F₁ individuals have red, axial flowers. The genes for flower color and location assort independently. Among the F₂ offspring, what is the probability of producing plants with white axial flowers?

Accepted Answer

A)  9/16 
B)  1/16 
C)  3/16 
D)  1/4 
A)  9/16 
B)  1/16 
C)  3/16 
D)  1/4

Question 11

Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this child's parents?

Accepted Answer

A)  One parent must be homozygous for the recessive allele; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. 
B)  One parent must be heterozygous; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. 
C)  Both parents must be heterozygous. 
D)  One parent must be homozygous dominant; the other parent must be heterozygous. 
A)  One parent must be homozygous for the recessive allele; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. 
B)  One parent must be heterozygous; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. 
C)  Both parents must be heterozygous. 
D)  One parent must be homozygous dominant; the other parent must be heterozygous.

Question 12

Skin color in a certain species of fish is inherited by a single gene with four different alleles. How many different types of gametes would be possible in this organism?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
A)  2 
B)  4 
C)  8 
D)  16

Question 13

Assuming independent assortment for all gene pairs, what is the probability that a cross between the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?

Accepted Answer

A)  1/2 
B)  1/16 
C)  1/8 
D)  3/4 
A)  1/2 
B)  1/16 
C)  1/8 
D)  3/4

Question 14

Which of the following statements correctly describes how Mendel accounted for the observation that traits had disappeared in the F₁ generation and then reappeared in the F₂ generation?

Accepted Answer

A)  New mutations were frequently generated in the F₂ progeny, causing traits that had been lost in the F₁ to reappear in the F₂. 
B)  The mechanism controlling the appearance of traits was different between the F₁ and the F₂ plants. 
C)  Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F₁. 
D)  Members of the F₁ generation had only one allele for each trait, but members of the F₂ had two alleles for each trait. 
A)  New mutations were frequently generated in the F₂ progeny, causing traits that had been lost in the F₁ to reappear in the F₂. 
B)  The mechanism controlling the appearance of traits was different between the F₁ and the F₂ plants. 
C)  Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F₁. 
D)  Members of the F₁ generation had only one allele for each trait, but members of the F₂ had two alleles for each trait.

Question 15

A black guinea pig crossed with a guinea pig with albinism produced 12 black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?

Accepted Answer

A)  Albinism is a recessive trait; black is a dominant trait. 
B)  Albinism is a dominant trait; black is incompletely dominant. 
C)  Albinism and black are codominant. 
D)  Albinism is a recessive trait; black is codominant. 
A)  Albinism is a recessive trait; black is a dominant trait. 
B)  Albinism is a dominant trait; black is incompletely dominant. 
C)  Albinism and black are codominant. 
D)  Albinism is a recessive trait; black is codominant.

Question 16

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

Accepted Answer

A)  the knowledge that multiple alleles are involved 
B)  the allele for blue hydrangea is completely dominant over the allele for pink hydrangea 
C)  the alleles are codominant 
D)  environmental factors such as soil pH affect the phenotype 
A)  the knowledge that multiple alleles are involved 
B)  the allele for blue hydrangea is completely dominant over the allele for pink hydrangea 
C)  the alleles are codominant 
D)  environmental factors such as soil pH affect the phenotype

Question 17

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

Accepted Answer

A)  Hh 
B)  HhTt 
C)  T 
D)  HT 
A)  Hh 
B)  HhTt 
C)  T 
D)  HT

Question 18

Which of the following statements best describes the addition rule of probability?

Accepted Answer

A)  the probability that two or more independent events will occur simultaneously 
B)  the probability that either one of two independent events will occur 
C)  the probability of producing two or more heterozygous offspring 
D)  the likelihood that a trait is due to two or more meiotic events 
A)  the probability that two or more independent events will occur simultaneously 
B)  the probability that either one of two independent events will occur 
C)  the probability of producing two or more heterozygous offspring 
D)  the likelihood that a trait is due to two or more meiotic events

Question 19

In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?

Accepted Answer

A)  A negative 
B)  O negative 
C)  B positive 
D)  AB negative 
A)  A negative 
B)  O negative 
C)  B positive 
D)  AB negative

Question 20

In rabbits, the homozygous genotype LᶜLᶜ has normal legs, LᶜLᶜ results in deformed legs, and LᶜLᶜ results in very short legs. The genotype FᴮFᴮ produces black fur, FᴮFᵇ brown fur, and FᵇFᵇ white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?

Accepted Answer

A)  25% 
B)  33% 
C)  100% 
D)  50% 
A)  25% 
B)  33% 
C)  100% 
D)  50%

Exam 14: Mendel and the Gene Idea

Which of the following statements is correct in describing the terms monohybrid cross and dihybrid cross?

What is the probability of producing the genotype AABBCC in a cross of individuals who both possess this genotype: AaBbCc?

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

Which of the following scenarios describes an example of epistasis?

Mendel's law of independent assortment has its basis in which of the following events of meiosis I?

Given the following genotypes for two parents, AABBCc × AabbCc, assume that all traits exhibit simple dominance and independent assortment. What proportion of the progeny of this cross will be expected to phenotypically resemble the first parent with the genotype AABBCc?

Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this child's parents?

Skin color in a certain species of fish is inherited by a single gene with four different alleles. How many different types of gametes would be possible in this organism?

Assuming independent assortment for all gene pairs, what is the probability that a cross between the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring?

Which of the following statements correctly describes how Mendel accounted for the observation that traits had disappeared in the F₁ generation and then reappeared in the F₂ generation?

A black guinea pig crossed with a guinea pig with albinism produced 12 black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

Which of the following statements best describes the addition rule of probability?

In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

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Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

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An Overview of Animal Diversity

An Introduction to Invertebrates

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Vascular Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

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Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

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