ABSTRACT
In this chapter, the authors explore eukaryotic cells, focusing on details of their structure, how they are related to prokaryotic cells, and how they evolved from ancestral prokaryotes. The germ cells are the only cells in the body capable of meiosis, the specialized cell divisions that give rise to mature sperm and egg cells. Diploid primordial germ cells migrate into the embryonic gonad and engage in repeated rounds of mitosis, to generate spermatogonia in males and oogonia in females. Its purpose is to generate genetic diversity, creating genetic differences between the daughter cells. After the DNA is replicated during S phase, the two sister chromatids of each chromosome are divided equally between the daughter cells during M phase. In advance of cell division, mitochondria increase in mass, and mtDNA molecules replicate before being segregated into daughter mitochondria that then need to segregate into daughter cells.
