Question 1

In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?

Accepted Answer

A) 1/4 
B) 1/8 
C) 1/16 
D) 1/32 
E) 1/64 
A) 1/4 
B) 1/8 
C) 1/16 
D) 1/32 
E) 1/64

Question 2

Use the following information to answer the questions below.
A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in this figure.
  
-A certain female's number 12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene. As cells in her ovaries undergo meiosis, her resulting eggs (ova)may have which of the following?

Accepted Answer

A) either two number 12 chromosomes with blue genes or two with orange genes 
B) either two number 19 chromosomes with long genes or two with short genes 
C) either one blue or one orange gene in addition to either one long or one short gene 
D) one chromosome 12 with one blue gene and one chromosome 19 with one long gene 
A) either two number 12 chromosomes with blue genes or two with orange genes 
B) either two number 19 chromosomes with long genes or two with short genes 
C) either one blue or one orange gene in addition to either one long or one short gene 
D) one chromosome 12 with one blue gene and one chromosome 19 with one long gene

Question 3

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

Accepted Answer

A) 1 
B) 1/2 
C) 1/4 
D) 1/6 
E) 0 
A) 1 
B) 1/2 
C) 1/4 
D) 1/6 
E) 0

Question 4

Use the following information to answer the questions below.
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a ?white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic.
-If true-breeding red long radishes are crossed with true-breeding white oval radishes, the ?F₁ will be expected to be which of the following?

Accepted Answer

A) red and long 
B) red and oval 
C) white and long 
D) purple and long 
E) purple and oval 
A) red and long 
B) red and oval 
C) white and long 
D) purple and long 
E) purple and oval

Question 5

What do we mean when we use 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 monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. 
C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one. 
D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. 
E) 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 monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. 
C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one. 
D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. 
E) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.

Question 6

Use the following description and figure to answer the questions below.
In a particular plant, leaf colour 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 Figure 14.1, 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) 1 and 2 
C) 2 and 3 
D) 4 only 
E) 1, 2, and 3 
A) 1 only 
B) 1 and 2 
C) 2 and 3 
D) 4 only 
E) 1, 2, and 3

Question 7

Use the following information to answer the questions below.
Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg).
-If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?

Accepted Answer

A) all +bt +vg heterozygotes 
B) 1/2 bent and 1/2 vestigial flies 
C) all homozygous + flies 
D) 3/4 bent to 1/4 vestigial ratio 
E) 1/2 bent and vestigial to 1/2 normal 
A) all +bt +vg heterozygotes 
B) 1/2 bent and 1/2 vestigial flies 
C) all homozygous + flies 
D) 3/4 bent to 1/4 vestigial ratio 
E) 1/2 bent and vestigial to 1/2 normal

Question 8

Use the following information to answer the questions below.
Skin colour in a certain species of fish is inherited via a single gene with four different alleles.
-One fish of this type has alleles 1 and 3 (S₁S₃)and its mate has alleles 2 and 4 (S₂S₄). If each allele confers a unit of colour darkness such that S₁ has one unit, S₂ has two units, and so on, then what proportion of their offspring would be expected to have five units of colour?

Accepted Answer

A) 1/4 
B) 1/5 
C) 1/8 
D) 1/2 
E) 0 
A) 1/4 
B) 1/5 
C) 1/8 
D) 1/2 
E) 0

Question 9

Refer to the following information to answer the questions below.
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 cacti have spines. Homozygous recessive nn cacti have no spines at all.
-If doubly heterozygous SsNn cacti were allowed to self-pollinate, the F₂ would segregate in which of the following ratios?

Accepted Answer

A) 3 sharp-spined:1 spineless 
B) 1 sharp-spined:2 dull-spined:1 spineless 
C) 1 sharp-spined:1 dull-spined:1 spineless 
D) 1 sharp-spined:1 dull-spined 
E) 9 sharp-spined:3 dull-spined:4 spineless 
A) 3 sharp-spined:1 spineless 
B) 1 sharp-spined:2 dull-spined:1 spineless 
C) 1 sharp-spined:1 dull-spined:1 spineless 
D) 1 sharp-spined:1 dull-spined 
E) 9 sharp-spined:3 dull-spined:4 spineless

Question 10

Use the following information to answer the questions below.
Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower colour is dominant to white (r). The heterozygous condition results in pink (Rr) flower colour.
-A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F₁ individuals?

Accepted Answer

A) ttRr-dwarf and pink 
B) ttrr-dwarf and white 
C) TtRr-tall and red 
D) TtRr-tall and pink 
E) TTRR-tall and red 
A) ttRr-dwarf and pink 
B) ttrr-dwarf and white 
C) TtRr-tall and red 
D) TtRr-tall and pink 
E) TTRR-tall and red

Question 11

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

Accepted Answer

A) 0% 
B) 25% 
C) 50% 
D) 75% 
E) 100% 
A) 0% 
B) 25% 
C) 50% 
D) 75% 
E) 100%

Question 12

Use the following information to answer the questions below.
Tay-Sachs disease is an inherited genetic disorder in which the gene sequence codes for an enzyme involved in lipid metabolism. Accumulation of lipids in the brain leads to seizures, blindness, loss of neural function, and early death. People can be carriers of this disease and only homozygotic offspring will die from this disorder.
-When the enzyme structure of a heterozygote carrier is examined, there is an equal number of functioning and non-functioning enzymes produced. This is an example of

Accepted Answer

A) complete dominance. 
B) co-dominance. 
C) incomplete dominance. 
D) pleitropy. 
E) epistasis. 
A) complete dominance. 
B) co-dominance. 
C) incomplete dominance. 
D) pleitropy. 
E) epistasis.

Question 13

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

Accepted Answer

A) incomplete dominance 
B) multiple alleles 
C) pleiotropy 
D) epistasis 
A) incomplete dominance 
B) multiple alleles 
C) pleiotropy 
D) epistasis

Question 14

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) 32 
E) 64 
A) 4 
B) 8 
C) 16 
D) 32 
E) 64

Question 15

Use the following information to answer the questions below.
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a ?white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic.
-In the F₂ generation of the above cross, which of the following phenotypic ratios would be expected?

Accepted Answer

A) 9:3:3:1 
B) 9:4:3 
C) 1:1:1:1 
D) 1:1:1:1:1:1 
E) 6:3:3:2:1:1 
A) 9:3:3:1 
B) 9:4:3 
C) 1:1:1:1 
D) 1:1:1:1:1:1 
E) 6:3:3:2:1:1

Question 16

Mendel accounted for the observation that traits which had disappeared in the F₁ generation reappeared in the F₂ generation by proposing that

Accepted Answer

A) new mutations were frequently generated in the F₂ progeny, "reinventing" traits that had been lost in the F₁. 
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 obscured by the dominant ones in the F₁. 
D) the traits were lost in the F₁ due to dominance of the parental traits. 
E) 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, "reinventing" traits that had been lost in the F₁. 
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 obscured by the dominant ones in the F₁. 
D) the traits were lost in the F₁ due to dominance of the parental traits. 
E) members of the F₁ generation had only one allele for each trait, but members of the F₂ had two alleles for each trait.

Question 17

Use the following pedigree shown below for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis.
  
-In each generation of this family after generation I, the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic)cases of this cancer (~ 63 years). What is the most likely reason?

Accepted Answer

A) Members of this family know to be checked for colon cancer early in life. 
B) Hereditary (or familial)cases of this cancer typically occur at earlier ages than do nonfamilial forms. 
C) This is pure chance; it would not be expected if you were to look at a different family. 
D) This cancer requires mutations in more than this one gene. 
E) Affected members of this family are born with colon cancer, and it can be detected whenever they are first tested. 
A) Members of this family know to be checked for colon cancer early in life. 
B) Hereditary (or familial)cases of this cancer typically occur at earlier ages than do nonfamilial forms. 
C) This is pure chance; it would not be expected if you were to look at a different family. 
D) This cancer requires mutations in more than this one gene. 
E) Affected members of this family are born with colon cancer, and it can be detected whenever they are first tested.

Question 18

Use the following information to answer the questions below.
Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower colour is dominant to white (r). The heterozygous condition results in pink (Rr) flower colour.
-If snapdragons are heterozygous for height as well as for flower colour, a mating between them will result in what ratio?

Accepted Answer

A) 9:3:3:1 
B) 6:3:3:2:1:1 
C) 1:2:1 
D) 27:9:9:9:3:3:3:1 
E) 9:4:3 
A) 9:3:3:1 
B) 6:3:3:2:1:1 
C) 1:2:1 
D) 27:9:9:9:3:3:3:1 
E) 9:4:3

Question 19

Use the following information to answer the questions below.
A certain (hypothetical) organism is diploid, has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in this figure.
  
-If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types?

Accepted Answer

A) only blue short gene eggs 
B) only orange short gene eggs 
C) one-half blue short and one-half orange short gene eggs 
D) three-fourths blue long and one-fourth orange short gene eggs 
E) three-fourths blue short and one-fourth orange short gene eggs 
A) only blue short gene eggs 
B) only orange short gene eggs 
C) one-half blue short and one-half orange short gene eggs 
D) three-fourths blue long and one-fourth orange short gene eggs 
E) three-fourths blue short and one-fourth orange short gene eggs

Question 20

Why did Mendel continue some of his experiments to the F₂ or F₃ generation?

Accepted Answer

A) to obtain a larger number of offspring on which to base statistics 
B) to observe whether or not a recessive trait would reappear 
C) to observe whether or not the dominant trait would reappear 
D) to distinguish which alleles were segregating 
E) to be able to describe the frequency of recombination 
A) to obtain a larger number of offspring on which to base statistics 
B) to observe whether or not a recessive trait would reappear 
C) to observe whether or not the dominant trait would reappear 
D) to distinguish which alleles were segregating 
E) to be able to describe the frequency of recombination

Exam 14: Mendel and the Gene Idea

In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

What do we mean when we use the terms monohybrid cross and dihybrid cross?

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

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

Mendel accounted for the observation that traits which had disappeared in the F₁ generation reappeared in the F₂ generation by proposing that

Why did Mendel continue some of his experiments to the F₂ or F₃ generation?

Introduction: Evolution and Themes of Biology

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

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

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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