MEIOSIS NON DISJUNCTION

Question 1

what happens when there is a failure of homologous chromosomes to separate properly during the anaphase of meiosis

Answer 1

produces gametes with the incorrect number of chromosomes
can arise spontaneously

Question 2

what are the three ways in which non disjunction can arise

Answer 2

1. failure of a pair of chromosomes to separate in meiosis I
2. failure of sister chromatids to separate in meiosis II
3. failure of sister chromatids to separate during meiosis

Question 3

what is it called when there is one copy of a chromosome

Answer 3

monosomy

Question 4

what is it called when there is a third copy of a chromosome

Answer 4

trisomy

Question 5

what is it called when there are three pairs of chromosomes

Answer 5

triploid

Question 6

what does 3 copies of chromosome 21 result in

Answer 6

down syndrome

Question 7

why do trisomies result in disorders

Answer 7

results in a greater quantity of proteins coded by the genes on that chromosome

Question 9

What is klinefelter syndrome

Answer 9

Some trisomies leading to developmental issues e.g. a male with multiple x chromosomes

Question 10

Turner syndrome

Answer 10

Most monosomies are lethal but a female can survive with just one x chromosome

Question 11

Triploid in plants

Answer 11

Lethal in humans
Some plant soecies can tolerate extra sets of chromosomes