Meiosis

Question 1

Phase sequence differences from mitosis?

Answer 1

One S phase followed by two M phases

Question 2

homologous recombination?

Answer 2

genes from paired homologous chromosomes during prophase 1 “cross over” to promote genetic variability

Question 3

genes from paired homologous chromosomes during prophase 1 “cross over” to promote genetic variability

Answer 3

homologous recombination

Question 4

Shugoshin (Sgo)’s function?

Answer 4

protects sister chromatids from being pulled apart during anaphase 1. They do get separated in anaphase 2.

Question 5

Nondisjunction

Answer 5

failure of chromosomes to separate normally in anaphase (can happen in meiosis 1 and 2 as well as mitosis). Creates aneuploidy (Ex: trisomy 21, Down’s Syndrome)

Question 6

When does spermatogenesis enter meiosis?

Answer 6

Spermatogonia enters at puberty. Continues the rest of the male’s life.

Question 7

When does Oogenesis (oogonium) initially enter meiosis?

Answer 7

before birth, arrested in meiosis 1 until puberty. no further oocytes produced after birth