cell division

Campbell and Reece, Chapter 12

In second grade, my health teacher read us the book "Mickey the microbe," and I learned that bacteria could "multiply and divide;" I was envious since I was not going to learn how to multiply and divide until 4th grade.

TRANSPARANCY (Fig. 13.8) Mitosis - understand concepts of 2n is diploid, prophase, metaphase, anaphase. Chromosome = colored body.

TRANSPARENCY (from AHSturtevant and GWBeadle, An introduction to genetics, Dover, New York, 1939 and 1962) indicates that, if there are homologues, they do not line up (contrast with meiosis, next lecture), early (prophase) DNA doubles, later (metaphase) centromeres divide
TRANSPARENCIES (Figs 12.5 a & b) your book's equivlent of the above

Cell division in eukaryotes to make genetically identical daughter cells
FUNDAMENTAL: multicellular, all cells have same genes (except germ cells)
spindles (centriole, not in plant, aster, spindle)

vs. in prokaryote - round DNA linked to membrane

TRANSPARENCY (Fig. 12.4) cell cycle
interphase is when the cell actually functions - unwound chromatin vs. condensed chromosomes
In many cell types, for instance brain (CNS Neurons) and heart (myocardial cells) - not divide, which is why stroke and heart attack are so damaging (no new cells replaced by mitosis) vs. in intestines, cells are constantly replaced by mitoses from strm cells since, in that milieu, cells digest themselves.
Centromere (on chromosome) = kinetochore (where microtubules attach)
metaphase push apart
metaphase plate
telophase when cells separate followed by cytokinesis.
cell cycle:interphase G1, S, G2, mitosis
G = gap, S = synthesis
arrest in G1 if postmitotic these are the cells which age

observe at metaphase block w drug colchicine
look different, i.e. where centromere is and size
TRANSPARENCY (Fig. 13.3) Your book's karyotype slide

TRANSPARENCY (Fig. 12.14) Very specific molecules control progress through cell cycle.
Many of the signal transduction cascades (previous chapter) control this cell cycle.
When things go wrong with these controls, cancer occurs.

This page was last updated 7/11/02

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