Fields: Fertilization Flashcards
(142 cards)
primordial germ cells undergo _____ during the weeks 4-5 and are now called oogonia
mitosis
when does mitosis cease for all oogonia
5th month
when does meiosis begin for all oogonia
5th month
when oogonia go through meiosis I what do they become
primary oocytes
what happens at birth for primary oocytes
they stop at prophase I of meiosis I
at puberty (age 12-13), what happens
meiosis I resumes and completes and meiosis II begins
what forms when meiosis II begins after puberty
secondary oocytes
23 pairs of homologous chromosomes are present in each cell
diploid
There are 2 sister chromatids/homologous chromosome or 2 x 23 = 46 chromatids
2n
1 of each pair of homologous chromosomes in each cell
1n (haploid)
when do breast buds start to form and also pubic hair
age 9-11
when does acne first appear; armpit hair; increase in height at fastest rate
after age 12
first period arrives; puberty begins (meiosis II begins)
around age 8-13
number of eggs will decrease from 7-10 million to ovulate only ____ throughout an individuals lifetime
400
when does mitosis of spermatogonia start
at puberty (9-14 yrs)
Type A or Type B is used for spermatogonia
Type B
after mitosis, what do spermatogonia become
primary spermatocytes
what do primary spermatocytes undergo to become secondary spermatocytes
meiosis I and II
_____ undergo differentiation and become active sperm (spermatozoa)
spermatids
males produce_____throughout lifetime
sperm
after meiosis II in spermatogenesis, what do you get
4 spermatids (4 cells)
after meiosis II in females, what do you get
1 egg (1 cell), with 3 polar bodies
haploid egg + haploid sperm=
diploid cell (zygote)
spermiogenesis
spermatid to spermatozoan (sperm)