Below are the descriptions of the individual strips.
To easily print out the strips please open “Strip
Sequence Template.docx.”
MALES
Meiosis initiated in puberty—1
Extra info: males are born with spermatogonial
stem cells that give rise to the cells that will enter
meiosis upon puberty. Continues from puberty to
death
Meiosis proceeds uninterrupted—2
Extra info: starts at meiotic entry and ends at cell
division
Symmetric cell division—3
After MI, cytokinesis is an even cell division
Symmetric cell division--4
After MII, cytokinesis is an even cell division;
there was no intervening cell cycle between
these divisions
4 functional germ cells—5
Biochemically distinct b/c coupled to meiosis are
species-specific differentiation programs
(spermatogenesis in humans) and genetically
distinct b/c contain ½ of the DNA content as starting
cell (haploid)
FEMALES
Meiosis initiated in fetal development—1
Cell population call primordial germ cells (PGCs)
travel to the fetal gonadal ridge in the fetus (~week
8-9 in human). Receive a cue to enter meiosis; do
DNA replication (S phase), homologous
recombination
Arrested at prophase of meiosis I—2
Arrest at end of recombination; intact chiasmata
hold chromosomes together, but the DSBs were
resolved (fixed) by the crossing over events; this is
where the oocytes grow in size and accumulate
materials to support meiosis, fertilization and early
embryonic development. Once fully-grown
transcription shuts off so having a maternal store of
RNAs to translate is very important for later events.
Resumption of meiosis upon puberty—3
Occurs upon LH surge in a cyclical fashion.
Enter MI where sisters remain attached and
homologs are segregated (remind students of
unique MI segregation)
Asymmetric cell division—4
Extrude small portion of cytoplasm in a nonfunctional cell called a polar body. Strategy to keep
all those materials to support meiosis, fertilization
and early embryonic development.
Arrest at metaphase of meiosis II—5
Won’t finish MII unless fertilized by sperm; next
division is asymmetric as well.
1 functional germ cell—6
1 cell b/c of the asymmetric divisions;
Biochemically distinct b/c coupled to meiosis are
species-specific differentiation programs
(oogenesis in humans) and genetically distinct
b/c contain ½ of the DNA content as starting cell
(haploid)