Exam #3 chpt 8

Question 1

mutation

Answer 1

driving force in evolution and key player in human health.

Question 2

chromosome structure mutations

Answer 2

breaking and rejoining of chromosomes for chromosome rearrangement

Question 3

imbalanced gene dosage

Answer 3

• harmful effects from duplications, deletions, and aneuploidy.
• not the right dosage can cause problems in protein production.

Question 4

duplications and deletions

Answer 4

• loop in prophase 1
• phenotypic consequences are from unbalanced gene dosage
• larger duplicated region the larger the difference in phenotype.

Question 5

haploinsufficiency

Answer 5

• one copy of a gene is insufficient for normal function

- deletion heterozygosity often produces haploinsufficiency

Question 6

unequal crossing over

Answer 6

• creates reciprocal duplications/deletions.

- one usually ends up with a duplication and the other a deletion.

Question 7

inversions

Answer 7

changes in gene expression if…

• inversions break point falls within a gene
• inversion places a gene in a new regulatory environment
• reduced fertility when recombination is within the inverted region
• forms a loop to line up inverted region

Question 8

inversion loops

Answer 8

• crossing over can cause unusual structures

- recombination can lose segments and mess up centromeres

Question 9

translocations

Answer 9

-reciprocal is most common but can also be nonreciprocal
-significant role in health
-reduce the percent of viable gametes
-can alter gene regulation
gene can be inactivated, translocation break point
occurs within gene
-can create hybrid genes by fusion between two separate genes

Question 10

robertsonian translocations

Answer 10

short arm and long arm are traded= creating a really long chromosome and a super short chromosome.
-small fragment usually lost.

human chromosome #2 robertsonian translocation from chimps
-14 and 21 also robertsonian.

Question 11

aneuploidy

Answer 11

when there are more or fewer copies than normal of a particular chromosome
-common forms
monosomy, and trisomy
-occurs frequently and virtually always harmful.

Question 12

nondisjunction

Answer 12

the failure of homologous chromosomes fr sister chromatid to separate at mitosis an meiosis
-leads to some gametes missing a chromosome or having an extra

Question 13

mitotic aneuploidy

Answer 13

• failure to separate sister chromatids
• detachment of chromosomes form spindle fibers
• important source fo genetic mosaicism
• nullisomy, monosomy, trisomy, tetrasomy

Question 14

nullisomy

Answer 14

2n-2

absence of both chromosomes of a homologous pair

Question 15

monosomy

Answer 15

2n-1

loss of a single chromosome

Question 16

tirsomy

Answer 16

2n+1
gain of a single chromosome
down syndrome #21

Question 17

tetrasomy

Answer 17

2n+2

two homologous chromosomes

Question 18

polyploidy

Answer 18

• possession of more than two sets of chromosomes
• major in flowering plant evolution and crops
• well tolerated in plants but rare and usually harmful in humans.

Question 19

autopolyploidy

Answer 19

sets of chromosomes of polyploid individual are derived from a single species

• can arise form nondisjunction
• usually a new species when a fertile polyploid forms.

Question 20

allopolyploidy

Answer 20

sets of chromosomes of a polyploid individual are derived from two or more species
-close relatives are sterile then chromosome doubling occurs and fertile allotetraploids are created.

Question 21

metacentric

Answer 21

chromosome arms are approximately the same length

Question 22

submetacentric

Answer 22

the centromere is DISPLACED towards one end producing a short arm and a long arm

Question 23

acrocentric

Answer 23

the centromere is NEAR one end, producing a long arm and a know at the other

Question 24

telocentric

Answer 24

centromere is at or ver NEAR one end