Week 5- Meiosis- Holy

Question 1

What are the two major functions of meiosis

Answer 1

2 functions of meiosis → create haploid cells and increase genetic diversity

Question 2

Compare meiosis and mitosis

Answer 2

Mitosis produces 2 identical daughter cells, meiosis produces 4 different haploid cells. Meiosis undergoes 1 S-phase with 2 M-phases, and they have pairing of homologous chromosomes with crossing over

Question 3

What are germ cells called prior to meiosis, after the first meiotic division, and after the second meiotic division?

Answer 3

Germ cells prior to meiosis → Primary **cyte
After 1st meiotic division → Secondary **cyte
Second meiotic division → Males = spermatids, Females = mature egg

Question 4

What are the two ways genetic diversity is generated in meiosis?

Answer 4

Genetic diversity → homologous recombination and independent assortment

Question 5

What is homologous recombination (crossing over)?

Answer 5

homologous recombination → when 2 parts of homologous chromosomes exchange genetic information

Question 6

What is random assortment?

Answer 6

Random assortment → when there is no order as to which chromosome (maternal or paternal) gets lined up on each side of the M plate to be pulled apart.

Question 7

Differentiate between haploid, diploid, and tetraploid.

Answer 7

Haploid = 1 copy of chromosome, Diploid = 2 copies of chromosome, Tetraploid = 4 copies of chromosome

Question 8

What is nondisjunction?

Answer 8

Nondisjunction → failure of chromosomes to separate accurately in anaphase, can happen in meiosis I or II or mitosis

Question 9

order of event for males

Answer 9

germ cell ⇒ spermatogonia ⇒ highly mitotically active ⇒ TONS of spermatogonia ⇒ birth ⇒ puberty ⇒ speratogonia can keep reproducing mitotically or ⇒ primary spermocyte ⇒ meiosis I ⇒ secondary spermocyte ⇒ meiosis II ⇒ 4 haploid spermatids

Question 10

order of events for females

Answer 10

germ cells: oogonia ⇒ highly mitotically active ⇒ TONS of oogonia ⇒ primary oocytes ⇒ meiosis I ⇒ arrest in prophase I ⇒ birth ⇒ stay in G0 state until puberty ⇒ handful of primary oocytes get stimulated each cycle to finish meiosis I ⇒ 1 polar body and one secondary oocyte ⇒ secondary oocyte either sloughs off if it is not fertilized or ⇒ gets fertilized ⇒ finish meiosis II which sperm invaginates

Question 11

names of male PGC derivatives

Answer 11

PGC ==> spermatogonia ==> primary spermocytes ==> secondary spermocytes ==> spermatids

Question 12

names of female PGC derivatives

Answer 12

PGC ==> oogonia ==> primary oocytes ==> secondary oocytes ==>

Question 13

shugoshin

Answer 13

protein that makes sure sister chromatids remain together during anaphase I