BIO 201 Lecture Notes - Lecture 25: Spindle Apparatus, Chromosome Segregation, Micrograph
18 Apr 2017
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Proliferation in bacteria: fission (cycle: replication of dna: chromosomal and plasmid dna are copied, cell lengthening and segregation of two chromosomes and plasmids, cytokinesis: daughter cells separate by pinching of plasma membrane. Proliferation in eukaryotes: the cell cycle : signal ex: growth factors, replication of dna, growth, mitosis and cytokinesis. Proliferation is more complex in eukaryotic cells because of 1,3,4. Dna is not condensed and therefore not visible so it appears as if nothing is happening (=g1,s, and g2) M-phase dna is condensed and is stained blue/black in the photomicrograph. What frog oocytes can teach us about the cell cycle. In the spring the female frog secretes progesterorone which causes her oocytes (egg precursor cells) to mature and be released for fertilization. Cells are arrested here in g2 until hormone progesterone signals oocytes to divide. Conclusion: something in the cytoplasm of progesterone-treated oocytes triggers meiosis. This something was referred to as maturation promoting factor (mpf)
