Ch 9: What I thought we were doing

Chapter 9

Four events necessary for prokaryotic and eukaryotic cells to divide:
-Must be a reproductive signal. Signal make come from inside or outside of cell —> initiates cell division.
-Replication of DNA and other vital cell components must occur so that each of the two new cells will have identical genes and complete cell functions.
-Cell must distribute the replicated DNA to each of the two new cells —> segregation
-New material must be added to the cell membrane (and cell wall in some organisms) in order to separate the two new cells by a process called cytokinesis.

Prokaryotes divide by binary fission - cell grows in size, replicates it's DNA, and divides into two new cells.

Eukaryotic cells divide by meiosis or mitosis.
-Development involves both cell reproduction and cell specialization.
Exceptions:
-Eukaryotic cells do NOT constantly divide.
-Eukaryotes usually have many elongated chromosomes.
-Eukaryotic cells have a distinct nucleus and so cytokinesis is distinct from segregation of the genetic material and can happen only after duplication of the entire nucleus.
-Cytokinesis proceeds differently in plant cells (with cell walls) then in animal cells (no cell wall).
-Meiosis occurs only in cells that produce the gametes (sex cells) involved in sexual reproduction.

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