Deck 8: Variation in Chromosome Structure and Number

Question 1

Gene duplications may be caused by

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

Answer 1

A

Question 2

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

Answer 2

D

Question 3

An inversion heterozygote contains

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

Answer 3

C

Question 4

Inversion loops can occur in

A) paracentric inversions.
B) pericentric inversions.
C) gene duplications.
D) reciprocal translocations.
E) both paracentric inversions and pericentric inversions.

Question 5

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 C D * E F G H

A) Terminal deletion
B) Interstitial deletion
C) Inversion
D) Gene duplication

Question 6

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

A) reciprocal translocation
B) terminal deficiency
C) interstitial deletion
D) gene duplication

Question 7

Which algebraic expression would be used to denote a trisomic organism?

A) 3n
B) 2n − 1
C) 2n + 1
D) 2n + 2

Question 8

Which type of chromosome has the longest p arm of the chromosome?

A) Acrocentric
B) Metacentric
C) Telocentric
D) Submetacentric

Question 9

Robertsonian translocations usually occur between what types of chromosomes?

A) Metacentric
B) Acrocentric
C) Telocentric
D) Submetacentric

Question 10

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

A) Translocations
B) Duplications
C) Deletions
D) Inversions

Question 11

Familial Down syndrome is a result of

A) inversion.
B) deficiency.
C) gene duplication.
D) translocation.

Question 12

Edward and Patau syndromes are examples of ________.

A) aneuploidy
B) allopolyploidy
C) autopolyploidy
D) translocations

Question 13

Inversions are contained within what percent of the human population?

A) Less than 1%
B) Approximately 2%
C) Approximately 5%
D) Greater than 10%

Question 14

Which of the following is not an example of euploidy?

A) Tetraploid
B) Polyploid
C) Triploid
D) Diploid
E) Aneuploid

Question 15

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

A) Robertsonian translocation
B) Unbalanced translocation
C) Balanced translocation
D) Chromosome loss

Question 16

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

Question 17

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 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

Question 18

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.

Question 19

Klinefelter and Turner syndromes are examples of

A) sex chromosome aneuploidy.
B) autosomal aneuploidy.
C) reciprocal translocations.
D) paracentric inversions.

Question 20

A translocation cross may occur in an individual that has a(n)

A) reciprocal translocation.
B) unbalanced translocation.
C) simple translocation.
D) All of the answers are correct

Question 21

The polytene chromosomes of Drosophila are an example of ________.

A) aneuploidy
B) polyploidy
C) translocations
D) inversion loops
E) None of the answers are correct

Question 22

Translocations and inversions represent a change in the total amount of genetic material in chromosomes.

Question 23

A diploid organism has a total of 36 chromosomes. Assuming all possible chromosome combinations are viable, if a mutant tetraploid version of this organism was created how many chromosomes would it have? If a mutant version of this organism was monosomic for chromosome 9 how many chomosomes would it have?

A) 144; 35
B) 72; 35
C) 144; 37
D) 72; 37

Question 24

A ________ translocation represents when a piece of one chromosome is attached to another chromosome.

A) simple
B) complex
C) reciprocal
D) balanced

Question 25

Homologous genes within a species are called paralogs.

Question 26

The failure of chromosomes to separate during anaphase is called ________.

A) synapsis
B) maternal effect
C) epistasis
D) nondisjunction

Question 27

Due to the formation of an inversion loop, sections of DNA may either be duplicated or deleted depending on the size of the inversion.

Question 28

The ends of chromosomes have areas of repeated DNA called centromeres.

Question 29

Which human cells exhibit endopolyploidy?

A) Sex cells
B) Nerve cells
C) All somatic cells
D) Liver cells
E) Red blood cells

Question 30

In meiotic nondisjunction, meiotic products can be n+1, n-1, or n depending on when nondisjunction occurs. If non disjunction occurs in Meiosis I, what is the outcome?

A) two trisomic and two monosomic products
B) one trisomic and three monosomic products
C) one trisomic, one monosomic, and two normal products
D) None of these answers are correct

Question 31

Hemophilia A is an X-linked blood clotting disorder. A normal man and a woman with hemophilia A have a child with Turner Syndrome. This child does not have hemophilia. In whom did non-disjunction occur? In meiosis I or meiosis II?

A) Woman; meiosis I
B) Woman; meiosis II
C) Man; meiosis I
D) Man; meiosis II
E) Woman; there is not enough information to tell if the nondisjunction happened in meiosis I or II.

Question 32

________ is a drug that is used to experimentally produce polyploidy in organisms.

A) Penicillin
B) Colchicine
C) Polymosca
D) Karyocine

Question 33

Polyploid plants tend to produce fewer fruits and flowers, be smaller in size, and not adapt as well to extreme environmental conditions as normal varieties.

Question 34

What type of plants are usually seedless?

A) Aneuploid
B) Diploid
C) Triploid
D) Tetraploid

Question 35

The short arm of a chromosome is denoted by the letter ________ and the long arm by the letter ________.

A) p, q
B) s, l
C) q, p
D) c, d

Question 36

Trisomy 8 usually leads to early miscarriage of a fetus. However, adult individuals have been found with cells that have three copies of chromosome 8 in them. How can this be?

A) The trisomic 8 adults likely have a mosaic region with trisomy 8.
B) The trisomic cells underwent complete nondisjunction.
C) The trisomic cells underwent a meiotic nondisjunction.
D) This individual must be triploid.

Question 37

What term describes an organism with two complete sets of chromosomes from two different species?

A) Tetraploid
B) Aneuploid
C) Allodiploid
D) Allotetraploid

Question 38

Which syndrome is not correctly matched to its aneuploid condition?

A) Down syndrome-trisomy 21
B) Edward syndrome-trisomy 18
C) Klinefelter syndrome-XO
D) Jacobs syndrome-XYY

Question 39

A photographic representation of the chromosomes of an organism is called a(n) ________.

A) allele variation
B) chromosomal spreading
C) chromosome picture
D) karyotype

Question 40

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

Question 41

The salivary amylase gene (AMY1) is present in two diploid copies in chimpanzees. Humans are known to have between 6-15 copies, an adaptation that is thought to be related to the high-starch diet of humans. This difference among humans is an example of

A) G banding.
B) copy number variation.
C) a simple translocation.
D) a reciprocal translocation.

Question 42

The common goldfish Carassius auratus has 100 chromosomes and is tetraploid. The goldfish therefore has ________ sets of chromosomes containing ________ chromosomes each.

A) 4; 25
B) 2; 50
C) 4; 100
D) 1; 100

Question 43

You perform comparative genomic hybridization. You correctly synthesize your red and green DNA, but you forget to treat the DNA with heat before you apply the samples to metaphase chromosomes. What will the ratio of green fluorescence to red fluorescence be?

A) 0
B) 1
C) 2
D) There will be no signal.

Question 44

In individuals with reciprocal tranlocations, meiosis can produce unbalanced gametes.

Question 45

Genetic abnormalities that occur before fertilization may result in some tissues of the body differing in their genetic composition. This is called mosaicism.

Question 46

The African clawed frog (Xenopus laevis) is allotetraploid, likely as a result of an interspecies mating long ago, followed by a duplication of the entire genome. Xenopus laevis is fertile and has a normal life cycle. In contrast, mules, the allodiploid offspring of a male donkey and a female horse, are generally sterile. Why can Xenopus reproduce and mules cannot?

A) Frogs are less sensitive to multiple copies of the genome than mammals.
B) In allotetraploid organisms each chromosome has a chromosome to pair up with in meiosis, whereas in allodiploid organisms they do not.
C) The two frogs that interbred to form the Xenopus laevis must have been more closely genetically related than the donkey and horse are.
D) The mule must have a genetic mutation that prevents it from reproducing.

Question 47

When scientists apply colchicine to plants to induce polyploidy, often tetraploid Is it possible that these tetraploids to be fertile, hence becoming a new species?

A) No, because all autotetraploids are sterile.
B) Yes, the tetraploids can produce diploid eggs and pollen.

Question 48

The aneuploid condition frequently affects the phenotype of an organism.

Question 49

SMAD4 is a tumor suppressor gene located on chromosome 18 that is known to be homozygously deleted in human lung cancer. If you were to perform comparative genomic hybridization using tissue from a lung cancer patient with a homozygous negative SMAD4 tumor, what ratio of green to red fluorescence would you expect?

A) A ratio of 1 on all of chromosome 18.
B) A ratio of 2 on the part of chromosome 18 containing the SMAD4 gene, with a value of 1 on the remainder of the chromosome.
C) A ratio of 0 on all of chromosome 18.
D) A ratio of 0 on the part of chromosome 18 containing the SMAD4 gene, with a value of 1 on the remainder of the chromosome.
E) A ratio of 1 on the part of chromosome 18 containing the SMAD4 gene, with a value of 0 on the remainder of the chromosome.

Question 50

A wholphin is a rare hybrid animal born from mating a female bottlenose dolphin with a male false killer whale. Wholphins are diploid. Interestingly, wholphins are fertile. What can you conclude from the fact that wholphins are fertile?

A) Wholphins are allotetraploid.
B) Dolphins and false killer whales likely have the same number of chromosomes.
C) Dolphins and false killer whales are actually the same species.
D) One of the parents must have been aneuploid.

Question 51

In polyploids, the chromosomal number is an integral multiple, whereas in aneuploids the number is plus or minus one or more from the diploid number.