Final: Meiosis Flashcards
(12 cards)
Crossover/recombination
during meiotic prophase, forms a new hybrid DNA molcule
Independent assortment
during meiosis I
happens along with reduction of diploid to haploid
When does meiosis occur during oogenesis?
prior to birth
meiosis 1 during oocyte maturation and meiosis 2 after fertilization
When does meiosis occur in spermatogenesis
mitotic divisions occur in testis of the adult
About what percent of fertilized eggs result in a live birth?
40-60%
What do telomeres do during meiotic prophase?
anchor chromosomes to nuclear envelope to facilitate chromosome movement and pairing
What does pairing do in meiotic prophase?
mediates homolog recognition and pairing
What do cytoskeletal motor proteins do in meiosis?
Drive chromosome movement and positioning by linking chromosomes to the cytoskeleton across the nuclear envelope
What do enzymes that create double stranded DNA breaks and repairs do in meiosis prophase?
Initiate homologous recombination by creating breaks
repair enzymes facilitate crossover and homolog pairing
What do components of the synaptonemal complexes do in meiosis prophase?
mediate and stabilize synapsis (tight pairing) of homologous chromosomes along their lengths
after recombination and dsDNA repair the complex breaks down and homologs are now held together by crossovers and cohesins
How are chromosomes attached to kinetochores during mitosis, meiosis 1, and meiosis 2?
mitosis: bipolar (sister chromatids separate)
meiosis 1: monopolar (homologs separate)
meiosis 2: bipolar
What are polar bodies?
small non functional cells produced during meiotic divisions of oocytes
