BIO 201 Lecture 25: Lecture 25 - Cell division and the cell cycle
6 Sep 2018
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Lecture 25: cell division and the cell cycle (ch. Proliferation in bacteria: fission (cycle: replication of dna: chromosomal and plasmid dna (if any) are copied, cell lengthening and segregation of the two chromosomes and plasmids, cytokinesis: daughter cells separate by pinching of plasma membrane. Bacteria are basically reproduction machines and usually only stop proliferating if starving (i. r. no atp) G1 = gap 1: growth, signals for proliferation. G2 = gap 2: dna checked for errors. M = mitosis: chromosome condensation, mitotic spindle assembly, chromosome segregation, cytokinesis (cell division) 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 this photomicrograph. What frog oocytes can teach us about the cell cycle. In the spring the female frog secretes progesterone which causes her oocytes (egg precursor cells) to mature and be released for fertilization.
