For males, they are produced in the Testes or male testicle.
The endosymbiotic theory explains that mitochondria and chloroplasts descended from the same type of bacteria. Symbiosis is an interaction between two organisms of different species, and <u>endo</u>symbiosis is a type of symbiosis in which one organism lives <u>inside </u>the other one. According to the endosymbiotic theory, a host cell ingested symbiotic bacteria, which specialized into mitochondria or chloroplasts. The evidence for this theory is that mitochondria and chloroplasts, like bacteria, have their own circular DNA. They also have their own transcriptional and translational machinery.
Anaphase I begins when the two chromosomes of each bivalent (tetrad) separate and start moving toward opposite poles of the cell as a result of the action of the spindle. Notice that in anaphase I the sister chromatids remain attached at their centromeres and move together toward the poles.
