Question 1

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*)indicates the centromere.
Before:A B C D * E F G H
After:A B C D * E F E F G H
A) terminal deficiency
B) interstitial deficiency
C) inversion
D) gene duplication

Accepted Answer

The sequence after the change shows a repetition of the segment "E F", indicating that a gene duplication has occurred.

Question 2

A translocation cross may occur in an individual which has which of the following?
A) reciprocal translocation
B) unbalanced translocation
C) simple translocations
D) All of these choices are correct.

Accepted Answer

A reciprocal translocation involves an exchange of genetic material between two non-homologous chromosomes. This can result in a translocation cross during meiosis if the individual produces gametes that contain the translocated chromosomes in a way that cannot properly pair and segregate during meiosis. Unbalanced translocations and simple translocations can also cause problems during meiosis, but they do not necessarily result in a translocation cross. Therefore, only choice A is the best answer.

Question 3

Which of following expressions denotes a trisomic organism?
A) 3n
B) 2n-1
C) 2n+1
D) 2n+2

Accepted Answer

A trisomic organism has an extra copy of one chromosome, therefore its total number of chromosomes is 2n+1. Choice A represents triploidy (three sets of chromosomes), choice B represents monosomy (only one copy of a chromosome), and choice D represents tetrasomy (four copies of a chromosome).

Question 4

Examples of euploidy include
A) diploidy.
B) triploidy.
C) tetraploidy.
D) polyploidy.
E) aneuploidy.

Accepted Answer

Euploidy refers to the correct number of chromosomes in a cell, meaning multiples of the haploid number (n). Diploidy (2n), triploidy (3n), tetraploidy (4n), and polyploidy (more than 4n) are all examples of euploidy. Aneuploidy, on the other hand, refers to an abnormal number of chromosomes, such as trisomy (three copies of a chromosome) or monosomy (one copy of a chromosome).

Question 5

Inversion loops can occur in which of the following?
A) paracentric inversions
B) pericentric inversions
C) gene duplications
D) reciprocal translocations
E) both paracentric inversions and pericentric inversions

Accepted Answer

Inversion loops can occur in both paracentric inversions and pericentric inversions. A paracentric inversion occurs when the inverted segment does not include the centromere, and a pericentric inversion occurs when the inverted segment includes the centromere. Inversion loops can often form during meiosis in these types of inversions, which can lead to meiotic recombination and potentially genetic disorders. Gene duplications and reciprocal translocations do not typically lead to inversion loops.

Question 6

The production of gene families,such as the globin genes,is the result of ________.
A) inversions
B) deficiencies
C) gene duplications
D) simple translocations
E) None of these choices are correct.

Accepted Answer

The production of gene families such as the globin genes is a result of gene duplications. Gene duplication is a process where a gene is copied and inserted into the genome, resulting in two or more copies of the same gene. Over time, these duplicate genes can accumulate mutations, leading to the formation of gene families.

Question 7

Edward and Patau syndromes are examples of ________.
A) aneuploidy
B) allopolyploidy
C) autopolyploidy
D) translocations

Accepted Answer

Edward and Patau syndromes are caused by aneuploidy, which is an abnormal number of chromosomes in a cell. In Edward syndrome, there is an extra copy of chromosome 18, while in Patau syndrome, there is an extra copy of chromosome 13.

Question 8

Which of the following would have the shortest p arm of the chromosome?
A) acrocentic
B) metacentric
C) telocentric
D) submetacentric

Accepted Answer

The telocentric chromosome has only one arm (q arm) and lacks a p arm, therefore it has the shortest p arm. Acrocentric chromosomes have a small p arm, but not as short as telocentric. Metacentric and submetacentric chromosomes have long p and q arms of approximately equal length.

Question 9

The effects of a deficiency on an organism are dependent on the importance of the missing genetic material.

Accepted Answer

This statement is true. The more important the missing genetic material is, the more severe the effects of the deficiency will be on the organism. However, if the missing genetic material is not critical to the survival and function of the organism, the effects may be minimal or even non-existent.

Question 10

Inversions are contained within what percent of the human population?
A) less than 1%
B) approximately 2%
C) approximately 5%
D) greater than 10%

Accepted Answer

Inversions are relatively rare structural variations, occurring in approximately 2% of the general population.

Question 11

Which of the following generally has the least effect on the phenotype of the individual who carries it?
A) Robertsonian translocation
B) unbalanced translocation
C) balanced translocation
D) All of these choices are equally detrimental to the phenotype.

Accepted Answer

Balanced translocation involves an exchange of genetic material between non-homologous chromosomes, but there is no loss or gain of genetic material. Therefore, balanced translocation generally has the least effect on the phenotype of the individual who carries it compared to Robertsonian and unbalanced translocations, which can cause partial or complete loss or duplication of genetic material, leading to significant phenotypic abnormalities.

Question 12

Robertsonian translocations usually occur between what types of chromosomes?
A) metacentric
B) acrocentric
C) telocentric
D) submetacentric

Accepted Answer

Robertsonian translocations typically occur between acrocentric chromosomes, which are chromosomes with the centromere located near the end. These include chromosomes 13, 14, 15, 21, and 22 in humans. The translocation involves the fusion of two acrocentric chromosomes, resulting in one larger chromosome and one smaller chromosome.

Question 13

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*)indicates the centromere.
Before:A B C D * E F G H
After:A B G F E * D C H
A) reciprocal translocation
B) pericentric inversion
C) paracentric inversion
D) gene duplication
E) None of the answers are correct.

Accepted Answer

The sequence after the change shows that the segment C D * E F G has been inverted, which includes the centromere, indicating a pericentric inversion.

Question 14

What causes gene duplications?
A) the crossing over of misaligned chromosomes
B) deletion of important genetic information
C) reciprocal translocations
D) position effect
E) None of these choices are correct.

Accepted Answer

Gene duplications can occur through unequal crossing over during meiosis, which can result in misaligned chromosomes and duplication of genetic material from one chromosome onto another.

Question 15

An inversion heterozygote contains which of the following?
A) two homologous chromosomes with inversions
B) two normal chromosomes
C) one normal chromosome and one chromosome with an inversion
D) None of these choices are correct.

Accepted Answer

An inversion heterozygote contains one normal chromosome and one chromosome with an inversion. They have one inverted copy of a chromosome and one non-inverted copy. A homozygous inversion would have two homologous chromosomes with inversions, but that is not the case for a heterozygote.

Question 16

What process is the cause of human genetic diseases such a cri-du-chat (or Lejeune)syndrome?
A) translocation
B) duplication
C) deletion
D) inversion

Accepted Answer

Cri-du-chat syndrome is caused by a deletion in chromosome 5. This means that a portion of the chromosome is missing, which can result in developmental delays, intellectual disability, and other physical characteristics associated with the syndrome. Translocation, duplication, and inversion can also cause genetic diseases, but they are not specifically associated with Cri-du-chat syndrome.

Question 17

Chromosomes may be identified based on which of the following characteristics?
A) location of the centromere
B) banding patterns
C) size of the chromosome
D) All of these choices are correct.

Accepted Answer

Chromosomes can be identified based on all of these characteristics: location of the centromere, banding patterns, and size of the chromosome. Therefore, the best choice is D, which includes all of these options.

Question 18

Variations in chromosome structure are important for which of the following reason(s)?
A) evolution of new species
B) may result in the production of abnormal offspring
C) may alter the phenotype of an organism
D) All of these choices are correct.

Accepted Answer

Variations in chromosome structure can lead to the evolution of new species as well as alter the phenotype of an organism. However, it can also result in the production of abnormal offspring due to genetic imbalances. Therefore, all the choices are correct.

Question 19

A loss of an internal portion of a chromosome is called a(n)________.
A) reciprocal translocation
B) terminal deficiency
C) interstitial deletion
D) gene duplication

Accepted Answer

A loss of an internal portion of a chromosome is called an interstitial deletion. A reciprocal translocation involves the exchange of segments between non-homologous chromosomes, a terminal deficiency is the loss of a segment from the end of a chromosome, and gene duplication involves the duplication of a segment of a chromosome.

Question 20

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*)indicates the centromere.
Before: A B C D * E F G H
After:A C D * E F G H
A) terminal deletion
B) interstitial deletion
C) inversion
D) gene duplication

Accepted Answer

An interstitial deletion occurred, where a segment of the chromosome between genes B and C was deleted.

Quiz 8: Variation in Chromosome Structure and Number

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before:A B C D E F G H After:A B C D * E F E F G H

A translocation cross may occur in an individual which has which of the following?

Which of following expressions denotes a trisomic organism?

Examples of euploidy include

Inversion loops can occur in which of the following?

The production of gene families,such as the globin genes,is the result of ________.

Edward and Patau syndromes are examples of ________.

Which of the following would have the shortest p arm of the chromosome?

The effects of a deficiency on an organism are dependent on the importance of the missing genetic material.

Inversions are contained within what percent of the human population?

Which of the following generally has the least effect on the phenotype of the individual who carries it?

Robertsonian translocations usually occur between what types of chromosomes?

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before:A B C D E F G H After:A B G F E * D C H

What causes gene duplications?

An inversion heterozygote contains which of the following?

What process is the cause of human genetic diseases such a cri-du-chat (or Lejeune) syndrome?

Chromosomes may be identified based on which of the following characteristics?

Variations in chromosome structure are important for which of the following reason(s) ?

A loss of an internal portion of a chromosome is called a(n) ________.

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before: A B C D E F G H After:A C D * E F G H

Quiz 8: Variation in Chromosome Structure and Number

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*) indicates the centromere. Before:A B C D * E F G H After:A B C D * E F E F G H

A translocation cross may occur in an individual which has which of the following?

Which of following expressions denotes a trisomic organism?

Examples of euploidy include

Inversion loops can occur in which of the following?

The production of gene families,such as the globin genes,is the result of ________.

Edward and Patau syndromes are examples of ________.

Which of the following would have the shortest p arm of the chromosome?

The effects of a deficiency on an organism are dependent on the importance of the missing genetic material.

Inversions are contained within what percent of the human population?

Which of the following generally has the least effect on the phenotype of the individual who carries it?

Robertsonian translocations usually occur between what types of chromosomes?

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*) indicates the centromere. Before:A B C D * E F G H After:A B G F E * D C H

What causes gene duplications?

An inversion heterozygote contains which of the following?

What process is the cause of human genetic diseases such a cri-du-chat (or Lejeune) syndrome?

Chromosomes may be identified based on which of the following characteristics?

Variations in chromosome structure are important for which of the following reason(s) ?

A loss of an internal portion of a chromosome is called a(n) ________.

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk (*) indicates the centromere. Before: A B C D * E F G H After:A C D * E F G H

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before:A B C D E F G H After:A B C D * E F E F G H

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before:A B C D E F G H After:A B G F E * D C H

Given the following sequence of genes on a chromosome,determine what change in chromosome structure occurred.The asterisk () indicates the centromere. Before: A B C D E F G H After:A C D * E F G H