7.5 chromosomal Abnormality

Question 1

Incorrect number of chromosomes

Answer 1

• nondisjunction
  (chromosomes don’t separate properly during meiosis)

Question 2

Breakage of chromosomes

Answer 2

• deletion
• duplication
• inversion
• translocation

Question 3

nondisjunction

Answer 3

chromosomes do not separate properly.
meiosis 1- homologous chromosomes do not separate properly
meiosis 2- sister chromatids fail to separate during

Question 4

What fails to separate if nondisjunction occurs in Meiosis 1?

Answer 4

homologous chromosomes

Question 5

What is the result for the gametes? Their future zygotes?

Answer 5

Gametes would be missing a chromosome or have an extra- zygotes would be diploid except for extra or missing chromosome.

Question 6

What fails to separate if nondisjunction occurs in Meiosis 2?

Answer 6

sister chromatids

Question 7

What is the result for the gametes? Their future zygotes?

Answer 7

Gametes could be normal, or would be missing a chromosome or have an extra- zygotes could be normal or would be diploid except for extra or missing chromosome.

Question 8

Nondisjunction results in

Answer 8

Offspring with wrong chromosome number

Question 9

Trisomy

Answer 9

cells are diploid except they have 3 copies of one chromosome type

2n+1

Question 10

Monosomy

Answer 10

cells are diploid except they have only one copy of a chromosome

2n-1

Question 11

deletion

Answer 11

gamete= missing gene
zygote= missing gene, only 1 instead of 2

Question 12

duplication

Answer 12

gamete= extra gene
zygote= extra gene, 3 instead of 2

Question 13

inversion

Answer 13

gamete= could be normal
zygote= might have trouble pairing chromosomes for meiosis

Question 14

translocation

Answer 14

gamete= could be normal , could be missing or extra genes
zygote= depends on which chromatids end up