Meiosis and X Inactivation Flashcards
What happens in the process of meiosis?
Diploid cells (in ovaries and testes) divide to form haploid cells
In meiosis, chromosomes can be reassorted/rearranged (become recombinant copies) .
What does this give rise to?
Creates genetic diversity.
Describe meiosis.
p.s even just read over what I’ve read to get a rough idea
-Cells undergo DNA replication in a way similar to cell division
-Homologous chromosomes undergo pairing to form bivalence
-This pairing enables the formation of bivalence, where the sisters undergo recombination meaning there’s an exchange of particular segments from the external and maternal copy.
-Bivalent chromosomes line up on the spindle of the first meiotic division, metaphase 1.
-In anaphase 1, the homologs separate.
-Cells undergo telophase 1.
-Cells undergo a second meiotic division, again, through going through the processes of prophase 2, metaphase 2, anaphase 2.
-Individual sister chromatids get separated to daughter cells.
Is DNA replication in meiosis quicker or slower than mitosis?
Slower
->don’t know why
What does the formation of bivalence’s allow?
The exchange of material between maternal and parental chromosomes.
What is oogenesis?
Process of egg formation.
What is spermatogenesis?
Process of sperm formation.
Which gamete goes through more cell divions?
Sperm
What is the danger associated with undergoing more cell divison?
More chance for mutations.
When does meiosis of eggs begin?
Early embryotic life.
When doe meiosis of sperm begin?
Puberty
How long does the production of sperm take?
60-65 days
How long does the production of eggs take?
10-15 years
Describe fertilisation.
Two haploid cells (egg, sperm) form 1 diploid cell (zygote) – develops into embryo
What gametes give male/female.
Male= XY
Female= XX
