Question 1

Which of following algebraic expressions would be used to denote a trisomic organism?
A) 3n
B) 2n - 1
C) 2n + 1
D) 2n + 2

Accepted Answer

A trisomic organism has an extra chromosome, so its chromosome number is represented as 2n + 1.

Question 2

The majority of autosomal aneuploid conditions are lethal, but sex chromosome aneuploids are
usually not lethal.

Accepted Answer

Sex chromosome aneuploids may cause mild to moderate physical and/or intellectual disability, but they are not usually lethal. Examples include Turner syndrome (45,X), Klinefelter syndrome (47,XXY), and Triple X syndrome (47,XXX).

Question 3

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 the answers are correct

Accepted Answer

A translocation cross is typically associated with reciprocal translocations, where segments of two non-homologous chromosomes are exchanged, leading to a cross-like configuration during meiosis.

Question 4

Human genetic diseases such a Cri-du-chat, Angelman syndrome and Prader-Willi syndrome are the result of which of the following?
A) Translocations
B) Duplications
C) Deletions
D) Inversions

Accepted Answer

Cri-du-chat, Angelman syndrome, and Prader-Willi syndrome are caused by deletions of specific chromosome segments.

Question 5

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 the answers are correct

Accepted Answer

Variations in chromosome structure can lead to evolutionary changes, cause abnormalities in offspring, and alter an organism's phenotype, making all the options correct.

Question 6

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 the answers are correct

Accepted Answer

Chromosomes can be identified based on their location of the centromere, banding patterns, and size.

Question 7

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 estimated to occur in approximately 2% of the human population.

Question 8

A loss of an internal piece of a chromosome is called a .
A) Reciprocal translocation
B) Terminal deficiency
C) Interstitial deletion
D) Gene duplication

Accepted Answer

An interstitial deletion refers to the loss of an internal segment of a chromosome, which is different from terminal deletions that occur at the end of a chromosome.

Question 9

Which of the following would have the shortest p arm of the chromosome?
A) Acrocentic
B) Metacentric
C) Telocentric
D) Submetacentric
E) All of the answers would be equal

Accepted Answer

Telocentric chromosomes have the centromere at the very end, resulting in the shortest p arm.

Question 10

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 the answers are correct

Accepted Answer

Gene duplications result in the production of gene families by creating multiple copies of a gene, which can then evolve new functions.

Question 11

Edwards and Patau syndrome are examples of .
A) Aneuploidy
B) Allopolyploidy
C) Autopolyploidy
D) Translocations

Accepted Answer

Edwards syndrome (Trisomy 18) and Patau syndrome (Trisomy 13) are examples of aneuploidy, which is a condition where there is an abnormal number of chromosomes in a cell.

Question 12

Gene duplications may be caused by which of the following?
A) The crossing over of misaligned chromosomes
B) Deletion of important genetic information
C) Reciprocal translocations
D) Position effect
E) None of the answers are correct

Accepted Answer

Gene duplications can occur when homologous chromosomes misalign during crossing over, leading to one chromosome with a duplicated segment and the other with a deletion.

Question 13

The effects of a deficiency on an organism is dependent on the size of the deletion and the importance
of the missing genetic material to the organism.

Accepted Answer

A deficiency's effects on an organism depend on the size of the deletion and the significance of the missing genetic material to the organism.

Question 14

Familial Down syndrome is a result of which of the following?
A) Inversion
B) Deficiency
C) Gene duplication
D) Translocation

Accepted Answer

Familial Down syndrome is caused by a Robertsonian translocation, where an extra part of chromosome 21 is attached to another chromosome, often chromosome 14.

Question 15

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 occur during meiosis in both paracentric and pericentric inversions to allow homologous chromosomes to align properly despite the inverted segment.

Question 16

Klinefelter and Turner syndromes are examples of which of the following?
A) Sex chromosome aneuploidy
B) Autosomal aneuploidy
C) Reciprocal translocations
D) Paracentric inversions

Accepted Answer

Klinefelter and Turner syndromes are caused by abnormalities in the number of sex chromosomes, making them examples of sex chromosome aneuploidy.

Question 17

Which of the following is not an example of euploidy?
A) Tetraploid
B) Polyploid
C) Triploid
D) Diploid
E) Aneuploid

Accepted Answer

Euploidy refers to a complete set of chromosomes, whereas aneuploidy refers to an abnormal number of chromosomes, either missing or extra. Therefore, aneuploidy is not an example of euploidy. A, B, C, and D are all examples of euploidy, representing different multiples of the haploid chromosome number.

Question 18

Which of the following rarely has an effect on the phenotype of the individual who carries it?
A) Robertsonian translocation
B) Unbalanced translocation
C) Balanced translocation
D) All of the answers are equally detrimental to the phenotype

Accepted Answer

A balanced translocation typically does not affect the phenotype because there is no loss or gain of genetic material; the genetic material is simply rearranged.

Question 19

Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred. (the * 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 20

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 the answers are correct

Accepted Answer

An inversion heterozygote has one normal chromosome and one chromosome with an inversion, meaning one chromosome has a segment that is reversed in orientation compared to the normal chromosome.

Quiz 8: Variation in Chromosome Structure and Number

Which of following algebraic expressions would be used to denote a trisomic organism?

The majority of autosomal aneuploid conditions are lethal, but sex chromosome aneuploids are usually not lethal.

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

Human genetic diseases such a Cri-du-chat, Angelman syndrome and Prader-Willi syndrome are the result of which of the following?

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

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

Inversions are contained within what percent of the human population?

A loss of an internal piece of a chromosome is called a .

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

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

Edwards and Patau syndrome are examples of .

Gene duplications may be caused by which of the following?

The effects of a deficiency on an organism is dependent on the size of the deletion and the importance of the missing genetic material to the organism.

Familial Down syndrome is a result of which of the following?

Inversion loops can occur in which of the following?

Klinefelter and Turner syndromes are examples of which of the following?

Which of the following is not an example of euploidy?

Which of the following rarely has an effect on the phenotype of the individual who carries it?

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

An inversion heterozygote contains which of the following?