Question 1

In Drosophila,the sex of a fly with the karyotype____ is male.

Accepted Answer

A) XX:2A 
B) XXY:2A 
C) XO:2A 
D) XYY:4A 
E) XXX:2A 
A) XX:2A 
B) XXY:2A 
C) XO:2A 
D) XYY:4A 
E) XXX:2A

Question 2

Individuals have been identified who have two different karyotypes,such as 45,X/46,XY or 45,X/46,XX.Such individuals are called ______.

Accepted Answer

A) heteromorphic 
B) homogametic 
C) trisomic 
D) mosaics 
E) heterogametes 
A) heteromorphic 
B) homogametic 
C) trisomic 
D) mosaics 
E) heterogametes

Question 3

In  Drosophila,the female is the ____ sex.

Accepted Answer

A) isogametic 
B) heterogametic 
C) homogametic 
D) mosaic 
E) genic balance 
A) isogametic 
B) heterogametic 
C) homogametic 
D) mosaic 
E) genic balance

Question 4

Klinefelter and Turner syndromes have how many chromosomes,respectively?

Accepted Answer

A) 47,46 
B) 46,46 
C) 45,47 
D) 47,45 
E) 46,45 
A) 47,46 
B) 46,46 
C) 45,47 
D) 47,45 
E) 46,45

Question 5

Give the sex of the following people assuming that the autosomes are present in the normal number.XO; XY; XXY.Answers are in order respectively .

Accepted Answer

A) female; male; male 
B) male; male; female 
C) female; male; female 
D) male; female; female 
E) male; male; male 
A) female; male; male 
B) male; male; female 
C) female; male; female 
D) male; female; female 
E) male; male; male

Question 6

The Protenor mode of sex determination is the ______ .

Accepted Answer

A) XO/YY scheme 
B) XX/XO scheme 
C) scheme based on single translocations in the X chromosome 
D) scheme based on F plasmids inserted into the FMR- 1 gene 
E) hermaphroditic scheme 
A) XO/YY scheme 
B) XX/XO scheme 
C) scheme based on single translocations in the X chromosome 
D) scheme based on F plasmids inserted into the FMR- 1 gene 
E) hermaphroditic scheme

Question 7

One form of hemophilia is caused by a sex- linked recessive gene.Assume that a man with hemophilia marries a phenotypically normal woman whose father had hemophilia.What is the probability that their first son will have hemophilia?

Accepted Answer

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

Question 8

One form of hemophilia is caused by a sex- linked recessive gene.Assume that a man with hemophilia marries a phenotypically normal woman whose father had hemophilia.What is the probability that they will have a daughter with hemophilia? Note: In this problem,you must include the probability of having a daughter in your computation of the final probability.

Accepted Answer

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

Question 9

A color- blind woman with Turner syndrome XO has a father who is color blind.Given that the gene for the color- blind condition is recessive and X- linked,provide a likely explanation for the origin of the color- blind and cytogenetic conditions in the woman.

Accepted Answer

A) nondisjunction in the father at meiosis I 
B) no abnormalities had to occur to produce this daughter 
C) nondisjunction in the father in meiosis I or II 
D) nondisjunction in the other in meiosis I or II 
E) nondisjunction in the mother in meiosis I and in the father in meiosis II 
A) nondisjunction in the father at meiosis I 
B) no abnormalities had to occur to produce this daughter 
C) nondisjunction in the father in meiosis I or II 
D) nondisjunction in the other in meiosis I or II 
E) nondisjunction in the mother in meiosis I and in the father in meiosis II

Question 10

Which of the following is not a tenant of the Lyon hypothesis?

Accepted Answer

A) X inactivation occurs early in development. 
B) X inactivation is passed down during mitosis. 
C) initial X inactivation is random. 
D) X inactivation of descendant cells is the same as the progenitor cell. 
E) X inactivation occurs on the maternal X chromosome. 
A) X inactivation occurs early in development. 
B) X inactivation is passed down during mitosis. 
C) initial X inactivation is random. 
D) X inactivation of descendant cells is the same as the progenitor cell. 
E) X inactivation occurs on the maternal X chromosome.

Question 11

In Drosophila,sex is determined by a balance between the number of haploid sets of autosomes and the number of ______.

Accepted Answer

A) centromeres 
B) telomeres 
C) X chromosomes 
D) nucleolar organizers 
E) Y chromosomes 
A) centromeres 
B) telomeres 
C) X chromosomes 
D) nucleolar organizers 
E) Y chromosomes

Question 12

What region is the major control center of X inactivation in mammals?

Accepted Answer

A) Xic 
B) NRY 
C) SRY 
D) MSY 
E) Barr Body 
A) Xic 
B) NRY 
C) SRY 
D) MSY 
E) Barr Body

Question 13

Under what condition might a human female have the XY sex chromosome complement?

Accepted Answer

A) She has an XX chromosome and a Y chromosome. 
B) The Y chromosome has an active Xist gene on it. 
C) The X chromosome has a mutation such that it is able to overpower the Y chromosome. 
D) This is not possible. 
E) This female would have one complete X chromosome and a Y chromosome that lacks SRY. 
A) She has an XX chromosome and a Y chromosome. 
B) The Y chromosome has an active Xist gene on it. 
C) The X chromosome has a mutation such that it is able to overpower the Y chromosome. 
D) This is not possible. 
E) This female would have one complete X chromosome and a Y chromosome that lacks SRY.

Question 14

Assume that you are told that a particular organism,Drosophila,has the XO chromosome complement.You are also told that the autosomal complement is a normal 2n.You know that in humans the XO complement is female determining.Would you be correct in assuming that the Drosophila sex for XO is also female? Choose the answer that includes the correct explanation.

Accepted Answer

A) No,the chromosomal basis for sex determination in Drosophila is based on the balance between the number of X chromosomes and haploid sets of autosomes. 
B) Yes,because sex determination in humans and insects is essentially the same. 
C) Yes,the presence of an X chromosome determines a female in both organisms. 
D) No,sex determination in Drosophila is dependent on the presence or absence of the Y chromosome. 
E) No,it takes two X chromosomes to produce a female in humans and a Y chromosome to produce a male in Drosophila. 
A) No,the chromosomal basis for sex determination in Drosophila is based on the balance between the number of X chromosomes and haploid sets of autosomes. 
B) Yes,because sex determination in humans and insects is essentially the same. 
C) Yes,the presence of an X chromosome determines a female in both organisms. 
D) No,sex determination in Drosophila is dependent on the presence or absence of the Y chromosome. 
E) No,it takes two X chromosomes to produce a female in humans and a Y chromosome to produce a male in Drosophila.

Question 15

Assume that a man who carries an X- linked gene has children.Assuming normal meiosis and random combination of gametes,the man would pass this gene to______ .

Accepted Answer

A) all of his sons 
B) half of his daughters 
C) all of his children 
D) half of his sons 
E) all of his daughters 
A) all of his sons 
B) half of his daughters 
C) all of his children 
D) half of his sons 
E) all of his daughters

Question 16

How many Barr bodies would one expect to see in cells of Turner syndrome females and Klinefelter syndrome males?

Accepted Answer

A) zero and two 
B) one and one 
C) zero and one 
D) one and zero 
E) zero and zero 
A) zero and two 
B) one and one 
C) zero and one 
D) one and zero 
E) zero and zero

Question 17

Which regions of the X chromosome recombine during meiosis?

Accepted Answer

A) the pseudoautosomal regions 
B) the heterochromain 
C) SRY 
D) the male- specific region of the Y 
E) the centromere 
A) the pseudoautosomal regions 
B) the heterochromain 
C) SRY 
D) the male- specific region of the Y 
E) the centromere

Question 18

What are the sex- chromosome constitution X and Y chromosomes of the inviable offspring resulting from a cross between a white- eyed female Xw XwY and a wild- type male normal chromosome complement in Drosophila melanogaster?

Accepted Answer

A) X+XwXw and YY 
B) X+XwY and X+XwXw 
C) YY and XwYY 
D) XwXwY and YY 
E) X+Y 
A) X+XwXw and YY 
B) X+XwY and X+XwXw 
C) YY and XwYY 
D) XwXwY and YY 
E) X+Y

Question 19

Genotypic sex determination does not in____ .

Accepted Answer

A) mammals 
B) birds 
C) reptiles 
D) round worms 
E) flies 
A) mammals 
B) birds 
C) reptiles 
D) round worms 
E) flies

Question 20

The accompanying figure is a pedigree of a fairly common human hereditary trait; the boxes represent males and the circles represent females.Filled in symbols indicate the abnormal phenotype.Given that one gene pair is involved,what is the inheritance pattern of the trait?

Accepted Answer

A) X- linked dominant 
B) X- linked recessive 
C) epistasis 
D) autosomal recessive 
E) autosomal dominant 
A) X- linked dominant 
B) X- linked recessive 
C) epistasis 
D) autosomal recessive 
E) autosomal dominant

Exam 7: Sex Determination and Sex Chromosomes

In Drosophila,the sex of a fly with the karyotype____ is male.

Individuals have been identified who have two different karyotypes,such as 45,X/46,XY or 45,X/46,XX.Such individuals are called ______.

In Drosophila,the female is the ____ sex.

Klinefelter and Turner syndromes have how many chromosomes,respectively?

Give the sex of the following people assuming that the autosomes are present in the normal number.XO; XY; XXY.Answers are in order respectively .

The Protenor mode of sex determination is the ______ .

One form of hemophilia is caused by a sex- linked recessive gene.Assume that a man with hemophilia marries a phenotypically normal woman whose father had hemophilia.What is the probability that their first son will have hemophilia?

A color- blind woman with Turner syndrome XO has a father who is color blind.Given that the gene for the color- blind condition is recessive and X- linked,provide a likely explanation for the origin of the color- blind and cytogenetic conditions in the woman.

Which of the following is not a tenant of the Lyon hypothesis?

In Drosophila,sex is determined by a balance between the number of haploid sets of autosomes and the number of ______.

What region is the major control center of X inactivation in mammals?

Under what condition might a human female have the XY sex chromosome complement?

Assume that a man who carries an X- linked gene has children.Assuming normal meiosis and random combination of gametes,the man would pass this gene to______ .

How many Barr bodies would one expect to see in cells of Turner syndrome females and Klinefelter syndrome males?

Which regions of the X chromosome recombine during meiosis?

What are the sex- chromosome constitution X and Y chromosomes of the inviable offspring resulting from a cross between a white- eyed female Xw XwY and a wild- type male normal chromosome complement in Drosophila melanogaster?

Genotypic sex determination does not in____ .

The accompanying figure is a pedigree of a fairly common human hereditary trait; the boxes represent males and the circles represent females.Filled in symbols indicate the abnormal phenotype.Given that one gene pair is involved,what is the inheritance pattern of the trait?

Introduction to Genetics

Mitosis and Meiosis

Mendelian Genetics

Extensions of Mendelian Genetics

Chromosome Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophages

Chromosome Mutations: Variation in Number and Arrangement

Extranuclear Inheritance

DNA Structure and Analysis

DNA Replication and Recombination

DNA Organization in Chromosomes

The Genetic Code and Transcription

Translation and Proteins

Gene Mutation,dna Repair,and Transposition

Regulation of Gene Expression in Bacteria

Transcriptional Regulation in Eukaryotes

Post-Transcriptional Regulation in Eukaryotes

Epigenetic Regulation in Eukaryotes

Recombinant Dna Technology

Genomic Analysis

Applications of Genetic Engineering and Biotechnology

Developmental Genetics

Cancer Genetics

Quantitative Genetics and Multifactorial Traits

Population and Evolutionary Genetics

CRISPR and Genomic Editing

DNA Forensics

Genomics and Precision Medicine

Genetically Modified Foods

Gene Therapy

Advances in Neurogenetics: The Study of Huntington Disease

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What are the sex- chromosome constitution X and Y chromosomes of the inviable offspring resulting from a cross between a white- eyed female X^wX^wY and a wild- type male normal chromosome complement in Drosophila melanogaster?