Topic 5-2

Question 1

what are the three main categories of chromosome mutations?

Answer 1

1) chromosome rearrangements
2) aneuploidy
3) polyploidy

Question 2

alters the strucutre of chromosomes

Answer 2

chromosome rearrangements

Question 3

alters the number of chromosomes

Answer 3

aneuploidy

Question 4

one or more complete sets of chromosomes are added

Answer 4

polyploidy

Question 5

what are the four types of chromosome rearrangements

Answer 5

• duplication
• deletion
• inversion
• translocation

Question 6

chromosome rearrangements are usually the result of _______ or ________

Answer 6

crossover errors, dsDNA breaks

Question 7

what is a chromosome duplication?

Answer 7

a mutation where a segment of the chromosome is duplicated

Question 8

what is a chromosome deletion?

Answer 8

a mutation where a segment of the chromosome is deleted

Question 9

what is a chromosome inversion?

Answer 9

a mutation where a segment of the chromosome is turned 180 degrees

Question 10

what is a chromosome translocation?

Answer 10

a mutation where a segment of a chromosome moves to a non-homologous chromosome or to another place on the same chromosome

Question 11

how are chromosome duplications/deletions detected?

Answer 11

loop structure in the normal chromosome (occurs in order for the homologous sequences of the chr to align)

Question 12

chromosomal duplication/deletion is often the cause of ________ in humans

Answer 12

red/green colourblindness

Question 13

what is the main problem with chr duplications?

Answer 13

abnormal development

Question 14

what is the main problem with chr deletions?

Answer 14

• homozygous = lethal
• heterozygous = whole chr can be lost, recessive mutations can be unmasked, some genes require two copies to properly function

Question 15

a type of chr deletion where one copy of a gene is not enough

Answer 15

haploinsufficiency

Question 16

duplications are important for:

Answer 16

evolution

Question 17

chr inversions reduce the rates of ______ during meiosis

Answer 17

recombination

Question 18

during both chr translocations and chr inversions, breaks may occur:

Answer 18

within a gene or on the regulatory region of a gene

Question 19

chr translocations can result in:

Answer 19

new linkage regions

Question 20

what are the three main causes of aneuploidy?

Answer 20

• deletion of centromere during mitosis and meioisis
• Robertsonian translocation
• nondisjunction during meiosis and mitosis

Question 21

______ is thought to result in the majority of aneuploidy in humans

Answer 21

failure/incomplete crossovers during meiosis

Question 22

aneuploidy is usually:

Answer 22

lethal

Question 23

down syndrome is caused by:

Answer 23

aneuploidy (three copies) of chr 21

Question 24

down syndrome is caused by:

Answer 24

spontaneous nondisjunction of chr

Question 25

maternal age increases are associated with:

Answer 25

higher rates of chr nondisjunction

Question 26

nondisjunction in a mitotic division produces:

Answer 26

genetic mosaicism

Question 27

genetic mosaicism for the sex chr produces a:

Answer 27

gynadromorph

Question 28

why is polyploidy important in agriculture?

Answer 28

used to produce larger plants and seedless fruits

Question 29

polyploidy from a single species

Answer 29

autopolyploidy

Question 30

polyploidy from two species

Answer 30

allopolyloidy

Question 31

autopolyploidy can arise through:

Answer 31

nondisjunction in mitosis or meiosis

Question 32

unequal chromosome numbers in gametes usually results in:

Answer 32

sterility

Question 33

allopolyploids may arise from:

Answer 33

hybridization between two species followed by chr doubling