Chromosome Mutations: Variation in Chromosome Number and Arrangement

Question 1

Specific Terminology Describes Variations in Chromosome Number:

Answer 1

• Aneuploidy
• Euploidy
• Polyploidy

Question 2

______, the Loss of a Single Chromosome, May Have Severe Phenotypic Effects

Answer 2

Monosomy

Question 3

______ Involves the Addition of a Chromosome to a Diploid Genome

Answer 3

Trisomy

Question 4

Trisomy (2n + 1 chromosomes) for the ______ has a less dramatic phenotype than trisomies for ______, which are often lethal.

Answer 4

sex chromosomes, autosomes

Question 5

______ results from trisomy of chromosome 21.

Answer 5

Down syndrome

Question 6

______ are often found in spontaneously aborted fetuses, but ______ are not.

This suggests that ______ gametes may be functionally impaired.

Answer 6

Trisomies, monosomies, monosomic

Question 7

______, in Which More Than Two Haploid Sets of Chromosomes Are Present, Is Prevalent in Plants

Answer 7

Polyploidy

Question 8

The naming of polyploids is based on the number of sets of chromosomes found:

Answer 8

triploid
tetraploid
pentaploid

Question 9

The naming of polyploids is based on the number of sets of chromosomes found:
• a ______ has 3n chromosomes

Answer 9

triploid

Question 10

The naming of polyploids is based on the number of sets of chromosomes found:
• a ______ has 4n chromosomes

Answer 10

tetraploid

Question 11

The naming of polyploids is based on the number of sets of chromosomes found:
• a ______, 5n chromosomes

Answer 11

pentaploid

Question 12

Polyploidy can originate by:

Answer 12

autopolyploidy
allopolyploidy

Question 13

Polyploidy can originate by:
• the addition of one or more sets of chromosomes identical to the haploid complement of the same species (______)

Answer 13

autopolyploidy

Question 14

Polyploidy can originate by:
• or the combination of chromosome sets from different species as a consequence of interspecific matings (______)

Answer 14

allopolyploidy

Question 15

Variation Occurs in the ______ and ______ of Chromosomes

Answer 15

Internal Composition, Arrangement

Question 16

Rearrangements of chromosome segments include:

Answer 16

• deletions
• duplications
• inversions
• nonreciprocal translocations
• reciprocal translocations

Question 17

A ______ Is a Missing Region of a Chromosome

Answer 17

Deletion

Question 18

When a chromosome breaks in one or more places and a portion of it is lost, the missing piece is referred to as a ______ (or a ______).

Answer 18

deletion, deficiency

Question 19

The deletion can occur:

Answer 19

terminal deletion
intercalary deletion

Question 20

The deletion can occur:
• near one end (______)

Answer 20

terminal deletion

Question 21

The deletion can occur:
• from the interior of the chromosome (______)

Answer 21

intercalary deletion

Question 22

______ results from a segmental deletion of a small terminal portion of the short arm of chromosome 5

Answer 22

Cri-du-chat

Question 23

The type of Notch phenotypic expression of recessive genes in association with a deletion in Drosophila is an example of ______.

Answer 23

pseudodominance

Question 24

A ______ Is a Repeated Segment of the Genetic Material

Answer 24

Duplication

Question 25

______ arise as the result of unequal crossing over during meiosis or through a replication error prior to meiosis.

Answer 25

Duplications

Question 26

Organisms have multiple copies of the ______ genes (______). This is an example of ______.

Answer 26

ribosomal RNA, rDNA, gene redundancy

Question 27

______ is another mechanism to increase the rRNA.

Answer 27

Gene amplification

Question 28

The ______ phenotype in Drosophila results from duplication.

Answer 28

Bar-eye

Question 29

______ Rearrange the Linear Gene Sequence

Answer 29

Inversions

Question 30

An ______ involves a rearrangement of the linear gene sequence rather than the loss of genetic information.

Answer 30

inversion

Question 31

In an ______, a segment of a chromosome is turned around 180° within a chromosome.

Answer 31

inversion

Question 32

types of inversion:

Answer 32

Paracentric inversion Pericentric inversion

Question 33

Synapsis of inverted chromosomes requires an ______.

Answer 33

inversion loop

Question 34

For a paracentric inversion crossover:

Answer 34

dicentric acentric

Question 35

For a paracentric inversion crossover: • one recombinant chromatid is ______ (two centromeres)

Answer 35

dicentric

Question 36

For a paracentric inversion crossover: • one is ______ (lacking a centromere)

Answer 36

acentric

Question 37

______ Alter the Location of Chromosomal Segments in the Genome

Answer 37

Translocations

Question 38

______ - movement of a chromosomal segment to a new location in the genome.

Answer 38

Translocation

Question 39

______ Translocation • involves exchange of segments between 2 nonhomologous chromosomes

Answer 39

Reciprocal

Question 40

______ Translocation • has an unusual synapsis configuration during meiosis

Answer 40

Reciprocal

Question 41

______ or ______ involves breaks at the extreme ends of the short arms of 2 nonhomologous acrocentric chromosomes

Answer 41

Robertsonian translocation, centric fusion

Question 42

______ in Humans Are Susceptible to Chromosome Breakage

Answer 42

Fragile Sites

Question 43

______ are more susceptible to chromosome breakage when cells are cultured in the absence of certain chemicals such as ______.

Answer 43

Fragile sites, folic acid

Question 44

______ (______) is the most common form of inherited mental retardation, affecting about 1 in ______ males and 1 in ______ females, and is a ______ trait.

Answer 44

Fragile X syndrome, Martin–Bell syndrome, 4000, 8000, dominant