Gametogenesis Flashcards
Meiosis:
Moves from 2n to n
Spermatogenesis end size
Meiosis separates the cytoplasm equally.
Stages of sperm:
germ cell - spermatogonium - primary spermatocyte - Secondary spermatocyte - Spermatids - Sperm cells
Oogenesis: symmetrical or asymmetrical?
asymmetrical
What bodies grow and fade as the egg matures?
Polar bodies containing excess DNA
Sertoli cells
Provide nutrients for developing spermatids
These structures allow flagellar bending
Dyneins
What is broadcast spawning?
Release of large numbers of gametes into an aquatic environment
Animal hemisphere
the upper hemisphere the usually contains the germinal vesicle (nucleus)
Vegetal hemisphere
bottom hemisphere typically containing mRNAs
GnRHs
Gonadotropin releasing hormones
What are two common gonadotropins?
Luteinizing hormone (LH) and follicle stimulating hormone (FSH)
Where is estrogen created?
Connective tissue cells in the ovary
Where is progesterone created?
Made especially by the corpus luteum
Estrogen and Progesterone together
inhibit hormone production by the hypothalamus and pituitary[inhibit gonadotrophin that causes ovulation, therefore stopping ovulation]
Progesterone function
Other than linking with estrogen to stop ovulation, it thickens the uterine lining.
hCG
Human Chorionic Gonadotropin : made by embryo, and stimulates the corpus luteum to maintain progesterone
RU486 and Progesterone
binds to the progesterone receptor, but does not activate signaling. Overall works to prevent preparation of the uterus for embryonic development.
Egg Jelly/ Cumulus Complex
Outer section of egg cell that sperm must digest.
Vitelline envelope / Zona pellucida
Second outer shell of egg cell that sperm bind to
Difference between oocytes and eggs
oocytes have not completed meiosis, whereas eggs have
Most mammalian and amphibian oocytes are arrested in what phase?
Metaphase II
What is MPF? [acronym]
Maturation Promoting Factor
What is CSF [acronym]
Cytostatic Factor
What is the relationship between CSF and MPF in regards to metaphase, and maturation?
Cytostatic factor causes arrest at metaphase II by PREVENTING the destruction of MPF.
What does MPF do?
MPF promotes maturation, but also results in the arrest of the egg cell at metaphase II.
How do egg cells progress beyond metaphase II?
During fertilization, Ca2+ levels rise in the cell, which destroys Emi2, allowing APC [anaphase promoting complex] to become active, progressing the cell.
Can ES or iPS cells produce gametes?
Yes.
