Question 1

What is the chromosomal system of sex determination in most species of ants and bees?

Accepted Answer

A) Haploid-diploid 
B) X-0 
C) X-X 
D) X-Y 
E) Z-W 
A) Haploid-diploid 
B) X-0 
C) X-X 
D) X-Y 
E) Z-W A

Question 2

Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?

Accepted Answer

A) Mitochondrial inheritance 
B) Chloroplast inheritance 
C) Genomic imprinting 
D) Infectious inheritance 
E) Sex-linkage 
A) Mitochondrial inheritance 
B) Chloroplast inheritance 
C) Genomic imprinting 
D) Infectious inheritance 
E) Sex-linkage B

Question 3

A man with hemophilia (a recessive, sex-linked condition)has a daughter of normal phenotype. She marries a man who is normal for the trait. What is the probability that a daughter of this mating will be a hemophiliac?
 That a son will be a hemophiliac?
 If the couple has four sons, what is the probability that all four will be born with hemophilia?

Accepted Answer

0; 1⁄2, 1/16

Question 4

In humans, male-pattern baldness is controlled by an autosomal gene that occurs in two allelic forms. Allele Hn determines nonbaldness, and allele Hb determines pattern baldness. In males, because of the presence of testosterone, allele Hb is dominant over Hn. If a man and woman both with genotype HnHb have a son, what is the chance that he will eventually be bald?

Accepted Answer

A) 0% 
B) 25% 
C) 33% 
D) 50% 
E) 75% 
A) 0% 
B) 25% 
C) 33% 
D) 50% 
E) 75%

Question 5

Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative?

Accepted Answer

A) AaBb × AaBb 
B) 46, XY or 46, XX 
C) vg+vgse+se × vgvgsese 
D) +2 × +3 
A) AaBb × AaBb 
B) 46, XY or 46, XX 
C) vg+vgse+se × vgvgsese 
D) +2 × +3

Question 6

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

Accepted Answer

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

Question 7

SRY is best described in which of the following ways?

Accepted Answer

A) A gene region present on the Y chromosome that triggers male development 
B) A gene present on the X chromosome that triggers female development 
C) An autosomal gene that is required for the expression of genes on the Y chromosome 
D) An autosomal gene that is required for the expression of genes on the X chromosome 
E) Required for development, and males or females lacking the gene do not survive past early childhood 
A) A gene region present on the Y chromosome that triggers male development 
B) A gene present on the X chromosome that triggers female development 
C) An autosomal gene that is required for the expression of genes on the Y chromosome 
D) An autosomal gene that is required for the expression of genes on the X chromosome 
E) Required for development, and males or females lacking the gene do not survive past early childhood

Question 8

Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?

Accepted Answer

A) The frequency of crossing over varies along the length of the chromosome. 
B) The relationship between recombination frequency and map units is different in every individual. 
C) Physical distances between genes change during the course of the cell cycle. 
D) The gene order on the chromosomes is slightly different in every individual. 
E) Linkage map distances are identical between males and females. 
A) The frequency of crossing over varies along the length of the chromosome. 
B) The relationship between recombination frequency and map units is different in every individual. 
C) Physical distances between genes change during the course of the cell cycle. 
D) The gene order on the chromosomes is slightly different in every individual. 
E) Linkage map distances are identical between males and females.

Question 9

You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown-eye locus. Where is a located on the chromosome?

Accepted Answer

About one-third of t

Question 10

What is the mechanism for the production of genetic recombinants?

Accepted Answer

A) X inactivation 
B) Methylation of cytosine 
C) Crossing over and independent assortment 
D) Nondisjunction 
E) Deletions and duplications during meiosis 
A) X inactivation 
B) Methylation of cytosine 
C) Crossing over and independent assortment 
D) Nondisjunction 
E) Deletions and duplications during meiosis

Question 11

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

Accepted Answer

A) Frequency of new meiosis 
B) Average of the ages of mother and father 
C) Age of the mother 
D) Age of the father 
E) Exposure of pregnant women to environmental pollutants 
A) Frequency of new meiosis 
B) Average of the ages of mother and father 
C) Age of the mother 
D) Age of the father 
E) Exposure of pregnant women to environmental pollutants

Question 12

Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation.

Accepted Answer

Because bananas are triploid, homologous

Question 13

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

Accepted Answer

A) It revealed new and unanticipated features of Mendel's pea plant varieties. 
B) It allowed the study of meiosis and mitosis, revealing parallels between behaviors of genes and chromosomes. 
C) It allowed scientists to see the DNA present within chromosomes. 
D) It led to the discovery of mitochondria. 
E) It showed genes functioning to direct the formation of enzymes. 
A) It revealed new and unanticipated features of Mendel's pea plant varieties. 
B) It allowed the study of meiosis and mitosis, revealing parallels between behaviors of genes and chromosomes. 
C) It allowed scientists to see the DNA present within chromosomes. 
D) It led to the discovery of mitochondria. 
E) It showed genes functioning to direct the formation of enzymes.

Question 14

What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

Accepted Answer

The disorder would a

Question 15

The frequency of crossing over between any two linked genes will be which of the following?

Accepted Answer

A) Higher if they are recessive 
B) Dependent on how many alleles there are 
C) Determined by their relative dominance 
D) The same as if they were not linked 
E) Proportional to the distance between them 
A) Higher if they are recessive 
B) Dependent on how many alleles there are 
C) Determined by their relative dominance 
D) The same as if they were not linked 
E) Proportional to the distance between them

Question 16

In another cross, a wild-type fruit fly (heterozygous for gray body color and red eyes)is mated with a black fruit fly with purple eyes. The offspring are as follows: wild type, 721; black-purple, 751; gray-purple, 49; black-red, 45. What is the recombination frequency between these genes for body color and eye color?
 Using information from problem 4, what fruit flies (genotypes and phenotypes)would you mate to determine the sequence of the body-color, wing-size, and eye-color genes on the chromosome?

Accepted Answer

6%. Wild type (heterozygous fo

Question 17

What is the chromosomal system for determining sex in mammals?

Accepted Answer

A) Haploid-diploid 
B) X-0 
C) X-X 
D) X-Y 
E) Z-W 
A) Haploid-diploid 
B) X-0 
C) X-X 
D) X-Y 
E) Z-W

Question 18

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Accepted Answer

A) Tortoiseshell females; tortoiseshell males 
B) Black females; orange males 
C) Orange females; orange males 
D) Tortoiseshell females; black males 
E) Orange females; black males 
A) Tortoiseshell females; tortoiseshell males 
B) Black females; orange males 
C) Orange females; orange males 
D) Tortoiseshell females; black males 
E) Orange females; black males

Question 19

What is the source of the extra chromosome 21 in an individual with Down syndrome?

Accepted Answer

A) Nondisjunction in the mother only 
B) Nondisjunction in the father only 
C) Duplication of the chromosome 
D) Nondisjunction or translocation in either parent 
E) It is impossible to detect with current technology 
A) Nondisjunction in the mother only 
B) Nondisjunction in the father only 
C) Duplication of the chromosome 
D) Nondisjunction or translocation in either parent 
E) It is impossible to detect with current technology

Question 20

Which of the following statements describes genomic imprinting?

Accepted Answer

A) It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele. 
B) It is greatest in females because of the larger maternal contribution of cytoplasm. 
C) It may explain the transmission of Duchenne muscular dystrophy. 
D) It involves an irreversible alteration in the DNA sequence of imprinted genes. 
A) It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele. 
B) It is greatest in females because of the larger maternal contribution of cytoplasm. 
C) It may explain the transmission of Duchenne muscular dystrophy. 
D) It involves an irreversible alteration in the DNA sequence of imprinted genes.

Exam 15: The Chromosomal Basis of Inheritance

What is the chromosomal system of sex determination in most species of ants and bees?

Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe?

Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative?

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

SRY is best described in which of the following ways?

Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?

You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown-eye locus. Where is a located on the chromosome?

What is the mechanism for the production of genetic recombinants?

The frequency of Down syndrome in the human population is most closely correlated with which of the following?

Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation.

Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics?

What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

The frequency of crossing over between any two linked genes will be which of the following?

What is the chromosomal system for determining sex in mammals?

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

What is the source of the extra chromosome 21 in an individual with Down syndrome?

Which of the following statements describes genomic imprinting?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

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: Harvesting Chemical Energy

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Molecular Basis of Inheritance

From Gene to Protein

Control of Gene Expression

Viruses

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 Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

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 Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

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