Chapter 6: Chromosome Mutations

Question 1

define aneuploidy

Answer 1

variations in a specific chromosome

Question 2

define euploidy

Answer 2

complete haploid sets of chromosome are present

multiples of n

Question 3

define polyploidy

Answer 3

more than two sets of chromosomes are present

more than 2 multiples of the haploid chromosome are found

Question 4

nondisjunction is the…

Answer 4

disruption of the normal distribution of chromosomes into gametes

Question 5

Monosomy is a type of _______ and is defined as the…..

Answer 5

aneuploidy

loss of one chromosome

Question 6

haploinsufficiency

Answer 6

when a single recessive gene is insufficient to provide life-sustaining function for an organism

Question 7

a trisomy is the

Answer 7

addition of a chromosome

Question 8

autopolyploidy is the…

Answer 8

addition of one or more sets of chromosomes identical to the haploid compliment of the species

Question 9

allopolyploidy is the…

Answer 9

combination of chromosome sets from different species

hybridization

Question 10

what type of chromosomes aberrations change the total amount of genetic information in chromosomes?

Answer 10

• deletions

- duplications

Question 11

what type of chromosomes aberrations rearranges the genetic material but the information stays the same?

Answer 11

inversions

translocations

Question 12

translocations occur between

Answer 12

nonhomologous chromosomes

Question 13

terminal deletions occur…

Answer 13

near one end of the chromosome

Question 14

intercalary deletions occur…

Answer 14

from the interior of a chromosome

Question 15

a paracentric inversion…

Answer 15

does not include centromere

Question 16

a pericentric inversion…

Answer 16

includes the centromere

Question 17

define alternate segregation

Answer 17

segregation pattern leading to a normal balanced gamete

Question 18

define adjacent segregation

Answer 18

segregation pattern leading to gametes containing duplications or deficiencies

Question 19

robertsonian translocation produces

Answer 19

• normal
• normal carrier
• trisomy 21
• lethal

Question 20

phenotypic variations result from

Answer 20

modifications at the chromosome level

Question 21

list 3 chromosomal modifications

Answer 21

1. change in total chromosome number
2. deletion or duplication of genes or chromosome segments
3. rearrangements of genetic material

Question 22

nondisjunction in the first meiotic division results in

Answer 22

no normal zygotes

Question 23

nondisjunction in the second meiotic division results in

Answer 23

1/2 normal zygotes

Question 24

down syndrome critical region is found on which chromosome?

Answer 24

chromosome 21

Question 25

down syndrome occurs due to nondisjunction of

Answer 25

chromosome 21

Question 26

75% of nondisjunction of chromosome 21 occur during

Answer 26

meiosis 1

Question 27

what is the source of trisomy in 95% of cases?

Answer 27

the ovum

Question 28

which two human trisomies survive to term?

Answer 28

- Patau syndrome - Edwards syndrome occur at chromosome 13 & 18

Question 29

familial down syndrome is due to the translocation of...

Answer 29

the bottom part of chromosome 21 onto another chromosome

Question 30

chromosomal aberrations occur due to...

Answer 30

exposure to chemicals or radiation

Question 31

what condition results from the segmental deletion of chromosome 5?

Answer 31

cri du chat

Question 32

duplications may result in

Answer 32

- gene redundancy - phenotypic variation - genetic variability

Question 33

gene amplification is a mechanism to

Answer 33

increase rDNA that codes for rRNA

Question 34

a crossover between paracentric inversion produces

Answer 34

dicentric chromatid and acentric chromatid

Question 35

what 2 segregation patterns result from translocation?

Answer 35

- alternate segregation | - adjacent segregation

Question 36

define alternate segregation

Answer 36

leads to normal and balanced gametes

Question 37

define adjacent segregation

Answer 37

leads to gametes containing duplications and deficiencies