The tetrad has 2 homologous pairs of chromosomes each containing identical twin chromatids. After crossing over, there are 2 homologous pairs each containing sister chromatids - they are no longer identical because parts have crossed over and it's already a sort of sexual event. Each oocyte only makes one definitive egg, plus 3 tiny polar bodies which contain the other chromosomes, but with little cytoplasm and no cellular machinery and which end up degenerating. Only one of the gametes needs to be a proper cell, so the male gametes produce 4 tiny things with a few mitochondria which work on fructose to make them motile. The proper cell is the ovum. Males make an awful lot of gametes all the time - up to half a billion in one ejaculation. By puberty females only have a few tens of thousands potential ova left, and in general only produce one definitive ovum each month
Good morning sir / mam Can I use this video for my channel for better experience for my students, i recently started a RU-vid channel in my mother language,my main theme was good understanding of the biology concepts in my mother Tung, with better visual effects,can you give permission then I used your video, to better way i present my class
Best video explanation but why didn't you explained the sub phase of prophase I searched for meiosis only to understand those sub phase Please explain and reply
