Question 1

A male that is produced from an unfertilized haploid egg is an example of what type of sex determination system?

Accepted Answer

A)  X-Y 
B)  Z-W 
C)  X-O 
D)  haplo-diploid 
A)  X-Y 
B)  Z-W 
C)  X-O 
D)  haplo-diploid D

Question 2

The genetic control of X-inactivation is governed by a short region on the X chromosome called the ________.

Accepted Answer

A)  Y-inactivation center (Yic) 
B)  condensation center 
C)  X-inactivation center (Xic) 
D)  X-initiation center 
A)  Y-inactivation center (Yic) 
B)  condensation center 
C)  X-inactivation center (Xic) 
D)  X-initiation center C

Question 3

Which of the following does not inactivate an X chromosome?

Accepted Answer

A)  mammals 
B)  Drosophila 
C)  C. elegans 
D)  humans 
A)  mammals 
B)  Drosophila 
C)  C. elegans 
D)  humans B

Question 4

With rare exceptions,a calico cat is likely to be female.

Accepted Answer

A) True 
 B)False

Question 5

Brown spotting of the teeth in humans is caused by a dominant X-linked gene. If a man with normal teeth marries a woman with brown teeth who had a father with normal teeth,then ________ of their daughters will have brown teeth.

Accepted Answer

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

Question 6

In humans,which sex is considered to be the heterogametic sex?

Accepted Answer

A)  male 
B)  female 
A)  male 
B)  female

Question 7

What gene is encoded in the Xic?

Accepted Answer

A)  Xce 
B)  Xist 
C)  TsiX 
A)  Xce 
B)  Xist 
C)  TsiX

Question 8

Studies of X-linked inheritance and sex chromosomes provided the evidence for which of the following?

Accepted Answer

A)  chromosomal theory of inheritance 
B)  particulate theory of inheritance 
C)  theory of natural selection 
D)  law of segregation 
E)  principle of dominance 
A)  chromosomal theory of inheritance 
B)  particulate theory of inheritance 
C)  theory of natural selection 
D)  law of segregation 
E)  principle of dominance

Question 9

Flowering plants will produce flowers that are dioecious,meaning that the male and female parts are contained within the same flower.

Accepted Answer

A) True 
 B)False

Question 10

Dosage compensation offsets the problems associated with differences in the number of ________ chromosomes in many species.

Accepted Answer

A)  sex 
B)  autosome 
C)  somatic 
D)  nuclear 
A)  sex 
B)  autosome 
C)  somatic 
D)  nuclear

Question 11

How many Barr bodies would an individual with a XXY genotype possess?

Accepted Answer

A)  0 
B)  1 
C)  2 
A)  0 
B)  1 
C)  2

Question 12

If a gene is located on the X chromosome,but not the Y,it is said to be an example of ________.

Accepted Answer

A)  autosomal inheritance 
B)  sex-linkage 
C)  reciprocal cross 
D)  pseudoautosomal inheritance 
E)  holandric 
A)  autosomal inheritance 
B)  sex-linkage 
C)  reciprocal cross 
D)  pseudoautosomal inheritance 
E)  holandric

Question 13

Pseudoautosomal inheritance occurs when

Accepted Answer

A)  a gene on an autosome is silenced by inactivation. 
B)  a gene on a Y chromosome has the same inheritance pattern as a gene on an X chromosome. 
C)  a gene on an autosome has the same inheritance pattern as a gene on a sex chromosome. 
D)  a gene on a sex chromosome has the same inheritance pattern as a gene on an autosome. 
A)  a gene on an autosome is silenced by inactivation. 
B)  a gene on a Y chromosome has the same inheritance pattern as a gene on an X chromosome. 
C)  a gene on an autosome has the same inheritance pattern as a gene on a sex chromosome. 
D)  a gene on a sex chromosome has the same inheritance pattern as a gene on an autosome.

Question 14

Red-green colorblindness is a X-linked recessive trait in humans.If a woman who is a carrier for red-green colorblindness marries a normal male,what percent of their sons will be colorblind?

Accepted Answer

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

Question 15

The coat color of calico cats is a result of ________.

Accepted Answer

A)  maternal inheritance 
B)  X-inactivation 
C)  imprinting 
D)  extra nuclear inheritance 
A)  maternal inheritance 
B)  X-inactivation 
C)  imprinting 
D)  extra nuclear inheritance

Question 16

The Lyon hypothesis attempts to explain the molecular mechanism of ________.

Accepted Answer

A)  X-inactivation 
B)  genomic imprinting 
C)  maternal inheritance 
D)  extra nuclear inheritance 
A)  X-inactivation 
B)  genomic imprinting 
C)  maternal inheritance 
D)  extra nuclear inheritance

Question 17

In a Z-W system,which is considered to be the homogametic sex?

Accepted Answer

A)  males 
B)  females 
A)  males 
B)  females

Question 18

A human individual has a karyotype that is XY but is phenotypically female.An explanation for this could be

Accepted Answer

A)  a deletion of the Sry gene on the Y chromosome, thus resulting in an female phenotype. 
B)  a translocation of the Sry gene to one of the X chromosomes has occurred, thus resulting in a female phenotype. 
C)  the Sry gene has been amplified 10 fold on the Y chromosome. 
D)  sex is determined by genes located on autosomes, not sex chromosomes. 
A)  a deletion of the Sry gene on the Y chromosome, thus resulting in an female phenotype. 
B)  a translocation of the Sry gene to one of the X chromosomes has occurred, thus resulting in a female phenotype. 
C)  the Sry gene has been amplified 10 fold on the Y chromosome. 
D)  sex is determined by genes located on autosomes, not sex chromosomes.

Question 19

Sex determination in humans and Drosophila is similar in the fact that

Accepted Answer

A)  the ratio of X chromosomes to sets of autosomes determines maleness or femaleness in both. 
B)  males in both will always have one Y chromosome, whereas females will not have a Y chromosome. 
C)  females lack X chromosomes. 
D)  males have one X chromosome and females have two X chromosomes. 
A)  the ratio of X chromosomes to sets of autosomes determines maleness or femaleness in both. 
B)  males in both will always have one Y chromosome, whereas females will not have a Y chromosome. 
C)  females lack X chromosomes. 
D)  males have one X chromosome and females have two X chromosomes.

Question 20

An example of a mechanism in which sex is determined by environmental factors is

Accepted Answer

A)  females are produced from fertilized eggs, whereas males are produced from unfertilized eggs. 
B)  when the male cares for the eggs, all of the offspring will be male, whereas if the female cares for the eggs, all of the offspring will be female. 
C)  fertilized eggs incubated at one temperature produce males, whereas eggs incubated at a different temperature produce females. 
D)  males will have a Y chromosome, whereas females will not have a Y chromosome. 
A)  females are produced from fertilized eggs, whereas males are produced from unfertilized eggs. 
B)  when the male cares for the eggs, all of the offspring will be male, whereas if the female cares for the eggs, all of the offspring will be female. 
C)  fertilized eggs incubated at one temperature produce males, whereas eggs incubated at a different temperature produce females. 
D)  males will have a Y chromosome, whereas females will not have a Y chromosome.

Exam 4: Sex Determination and Sex Chromosomes

A male that is produced from an unfertilized haploid egg is an example of what type of sex determination system?

The genetic control of X-inactivation is governed by a short region on the X chromosome called the ________.

Which of the following does not inactivate an X chromosome?

With rare exceptions,a calico cat is likely to be female.

Brown spotting of the teeth in humans is caused by a dominant X-linked gene. If a man with normal teeth marries a woman with brown teeth who had a father with normal teeth,then ________ of their daughters will have brown teeth.

In humans,which sex is considered to be the heterogametic sex?

What gene is encoded in the Xic?

Studies of X-linked inheritance and sex chromosomes provided the evidence for which of the following?

Flowering plants will produce flowers that are dioecious,meaning that the male and female parts are contained within the same flower.

Dosage compensation offsets the problems associated with differences in the number of ________ chromosomes in many species.

How many Barr bodies would an individual with a XXY genotype possess?

If a gene is located on the X chromosome,but not the Y,it is said to be an example of ________.

Pseudoautosomal inheritance occurs when

Red-green colorblindness is a X-linked recessive trait in humans.If a woman who is a carrier for red-green colorblindness marries a normal male,what percent of their sons will be colorblind?

The coat color of calico cats is a result of ________.

The Lyon hypothesis attempts to explain the molecular mechanism of ________.

In a Z-W system,which is considered to be the homogametic sex?

A human individual has a karyotype that is XY but is phenotypically female.An explanation for this could be

Sex determination in humans and Drosophila is similar in the fact that

An example of a mechanism in which sex is determined by environmental factors is

Overview of Genetics

Reproduction and Chromosome Transmission

Mendelian Inheritance

Extensions of Mendelian Inheritance

Extranuclear Inheritance, Imprinting, and Maternal Effect

Genetic Linkage and Mapping in Eukaryotes

Variation in Chromosome Structure and Number

Genetics in Bacteria

Genetics of Viruses

Molecular Structure of DNA and RNA

Molecular Structure of Chromosomes and Transposition

Dna Replication and Recombination

Gene Transcription and RNA Modification

Translation of MRNA

Gene Regulation in Bacteria

Gene Regulation in Eukaryotes

Non-Coding Rnas

Gene Mutation and DNA Repair

Molecular Technologies

Genomics

Medical Genetics and Cancer

Population Genetics

Quantitative Genetics

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