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2013-01-23 15:50:20
BIO 220

Ch 49
Show Answers:

  1. What is gametogenesis?
    gamete formation and maturation
  2. Explain it in females?
    • egg undergoes meiosis, which is formation, at the same time she's maturing (called oogenesis)
    • - formation and maturing are happening simultaneously
  3. In oogenesis, what happens with the egg?
    egg gets bigger and bigger because she has to bring structures for early development due to the fact that the fertilized egg and early embryo don't turn on the zygotic genome at first
  4. In males, explain gametogenesis.
    • two events that take place (not two different process) at different times
    • Gametogenesis is made up of spermatogenesis, which is formation, and spermeogenesis, which is maturation
  5. Explain the sperm cell at the end of spermatogenesis.
    at the end, the cell doesn't look like a sperm, but it is haploid. Spermeogenesis must change it anatomically to resemble sperm 
  6. Explain sperm at the end of gametogenesis.
    • sperm is very small to what it orignally was 
    • Function: to bring haploid nucleus to egg only
    • Very little cytoplasm
    • Whereas the female has structures, the sperm loses material.
  7. Explain a similarity of gametogenesis in both males and females.
    • both rely on pituitary hormones
    • The anterior pituitary makes lots of hormones: FSH and LH, both of which are necessary for gametogenesis in Females and Males
  8. Male Gametogenesis: 
    When does stuff begin to happen?
    • nothing happens in testes until puberty; sperm not produced prior to puberty.
    • From puberty on, spermatogenesis and spermiogenesis are continuous until the end of sexual life.= constantly making sperm
  9. What is the set date for male gametogenesis?
    • no set date
    • i slows down, but doesn't stop like females with menopause
    • no end, but decreases with age
  10. In females, when does gametogenesis begin to happen?
    • One process (formation and maturation): begins process when in mom's uterus; still an embryo
    • every stem cell (oogonia) in follicle commits to meiosis at the same time
    • All are made; She has no oogonia at birth
    • All begin Meiosis I while she is still in womb
    • Stops at birth and doesn't start again till puberty (once a month; not continuous)
  11. Set end for female gametogenesis?
    • menopause
    • - no longer produces viable gametes
  12. Difference in terms of products of cells in male and female gametogenesis.
    • four sperm at end of gametogenesis (one spermatophyte makes four sperm)
    • one primary oocyte makes one egg
  13. Cell you will find in testes all the time is the __.
  14. What is the spermatogonium?
    • diploid cell/ provides cells that will give rise to sperm
    • it is the stem cell or the primordial germ cell: cell that will give rise to gametes
    • produces trillions of sperm
  15. True or False: Not every spermatogonium will commit to Gametogenesis.
  16. A male always has __ and they always divide __.
    • spermatogonium
    • mitotically
  17. a.       If he is going to make a sperm, some __have to commit to __, which means they __
                                                                   i.      When they commit to meiosis, changes take place= __
    b.      Part of commitment is __; cant go back and divide __; committed
    • spermatogonia
    • meiosis
    • no longer divide mitotically
    • primary spermatocyte
    • replication
    • mitotically
  18. \ 1.       Cell that begins Gametogenesis in the male is the primary __, not the __
    • spermatocyte
    • spermatogonium
  19. Which is the uncommitted stem cell?
    Which is the committed one?
    • unco: spermatogonium
    • comm: spermatocyte
  20. Explain meiosis in terms of the spermatocyte.
    • a.       Meiosis 1 (2n/4n)
    •                                                                i.       Spermatocyteà secondary spermatocyte (1n/2n)
    • b.      Meiosis II (1n/2n):
    •                                                                i.      Secondary spermatocyteà spermatid (1n/1n) completely haploid
    • c.       Spermatidà Sperm= spermeiogenesis
    •                                                                i.      No divisioin, but changes anatomically