Gametogenesis Flashcards
What is gametogenesis
the formation of the gametes by meiosis in the sex organs
What is spermatogensis?
the formation of the sperm in the testes (spermatoza)
what is a primordial germ cell
Cells that divide by meosis to ultimtley form the sperm and ova
What is the first step in spermatogenisis 1/5
The diploid primoridal germ cell divides several times by mitosis to form diploid spermatogonia
spermatogenisis 2/5
the spermatognoia then grow without further division until they are big enough to be called primary spematocytes
spermatogenisis 3/5
The spermatocytes undergo meiosis. The first meiotic division results in 2 haploid cells called secondary spermatocytes
spermatogenisis 4/5
The second meiotic division results in 4 haploid cells called spermatids
spermatogenisis 5/5
The spermatids then differentiate into the tubules of the testes to from spermatozoa the active gametes capable of fertilising an ovum
How are primary spermatocytes form
The spermatognia then grow without further divison until they are big enough
How are spermatids formed
Spermatocytes undergo meiosis . The first meiotic division results in 2 haploids cells called secondary spermatocytes
The second meiotic division results in 4 haploid cells called spermatids
How is spermatozoa formed
The spermatids then differentiate in the tubules of the testes to form spermatozoa
What is pollination
transfer of pollen from the anther to the stigma often from one flower to another
What is the role of the pollen tube in fertilsation
tube that grows out of a pollen grain down the style , into the ovary and through the mircropyle of the ovule to carry 2 male nuclei to the ovule
What is external fertilsation
fertilsation that occurs female and male gametes are released outside parental bodies
What is sporophyte generation
diploid generation in plants that produces spores by meiosis
