Gamete formation Flashcards
Which are the only cell found in the body that can undergo both meiosis and mitosis?
Primordial germ cells
What do Primordial germ cells produce?
Sperm/Eggs
Talk through oogenesis
(6 stages) Which stages are before birth/after puberty?
Before birth:
1) Primordial germ cells undergo mitosis
2) PMCs differentiate into oogonia in gonad and continue mitosis - some into meiosis I
3) Arrest as primary oocytes in prophase I
After puberty:
1) Continues meiosis I = secondary oocyte and polar body
2) Begins meiosis II - arrests in metaphase II
3) Completes meiosis on fertilisation - 1 or 3 more polar bodies.
When is meiosis of female gametes complete? In which two places of oogenesis does meiosis arrest?
Only on fertilisation by sperm.
Arrests in prophase I at birth until puberty- primary oocytes.
After puberty - Arrests in metaphase II as secondary oocyte - until fertilised - meiosis completes
What is a primordial follicle?
A primary oocyte surrounded by flattened epithelial cells
What is a primordial follicle?
A primary oocyte surrounded by flattened epithelial cells
Do PGCs differentiate in men before puberty?
No spermatogenesis only occurs at puberty
Do PGCs differentiate in men before puberty?
No spermatogenesis only occurs at puberty
Do male or female gametes experience more mutations?
Male as much more mitosis/meiosis.
What is the most common cause of miscarriage?
Chromosomal abnormality in gamete
