Chromosome Mutations: Variation in Number & Arrangement

Question 1

Having missing or extra chromosomes is a condition called

Answer 1

aneuploidy (2n + x)

Question 2

represents a change in the whole set of chromosomes

Answer 2

Euploidy (Xn)

Question 3

Polyploidy means that…

Answer 3

More than 2 haploid sets of Chromosomes are present

Question 4

Why are polyploid plants bigger than their diploid counterparts?

Answer 4

larger than diploid relatives due to larger cell size rather than a greater cell number

Question 5

Each additional set of chromosomes is identical to the parent species

Answer 5

Autopolyploidy

Question 6

an alkaloid derived from the autumn crocus plant

Answer 6

Colchicine

Question 7

How does Colchicine stop cell division

Answer 7

interferes w/ spindle formation, replicated chromosomes cannot separate at anaphase and do not migrate to the opposite poles

Question 8

What is monosomy?

Answer 8

The loss of a single chromosome from an otherwise diploid genome is called monosomy (2n -1)

Question 9

What is trisomy?

Answer 9

The gain of one chromosome results in trisomy (2n + 1)

Question 10

Klinefelter syndrome (47,XXY)
Down Syndrome
Patau’s Syndrome
Edward’s Syndrome
Cri-du-chat Syndrome

are all examples of trisomy (True or False)

Answer 10

False (Answer: Cri-du-chat Syndrome is a partial monosomy, a deletion, 46,-5p)

Question 11

Why does chromosome variation occur?

Answer 11

a random error during the production of gametes, a phenomenon referred to as nondisjunction, whereby paired homologs fail to disjoin during segregation

Question 12

Why does the risk of offspring increase as maternal age increases?

Answer 12

each ovum that is released has been arrested in meiosis, thus women produce ova that are significantly older

Question 13

What is deletion?

Answer 13

When chromosome breaks in one or more places and a portion of it is lost, the missing piece is called a deletion

Question 14

deletion near one end of the chromosome is called?

Answer 14

terminal deletion

Question 15

the deletion that occurs within the interior of the chromosome is called?

Answer 15

intercalary deletion

Question 16

Chromosome Inversion means

Answer 16

segment of a chromosome is turned around 180 degrees within a chromosome

Question 17

The inverted segment may be short or quite long and may or may not include the centromere

Answer 17

paracentric inversion

Question 18

pericentric inversion

Answer 18

If the centromere is part of the inverted segment

Question 19

Duplication

Answer 19

When any part of the genetic material—a single locus or a large piece of a chromosome—is present more than once in the genome, it is called a duplication

Question 20

movement of a chromosomal segment to a new location

Answer 20

Translocation

Question 21

Reciprocal translocation

Answer 21

the exchange of segments between two nonhomologous chromosomes

Question 22

breaks at the extreme ends of the short arms of two nonhomologous acrocentric chromosomes and the larger segments fuse at their centromeric region is what type of translocation?

Answer 22

Robertsonian translocation

Question 23

caused by the FMR1 gene

Answer 23

Fragile X/Martin Bell Syndrome (FXS)

Question 24

Fragile X/Martin Bell Syndrome (FXS) happens because of…

Answer 24

the FMR1 gene, which has CGG is repeated abnormally in an untranslated area adjacent to the coding sequence of the gene (normal is 6-54 while FXS has 55-230)