HB+Cell+Division

=__**Cell Division (Chapter 18)**__=

What are the three stages of interphase. Describe each phase.

 * In G1, a cell doubles organelles and accumulates materials for DNA synthesis.
 * In S, DNA replication occurs
 * In G2, a cell synthesizes proteins needed for cell division.

How does interphase prepare a cell for cell division?

 * When the cell gets ready to divide it grows larger, number of organelles doubles, and the amount of chromatin doubles as DNA synthesis occurs. For mammalian cells, interphase lasts for about 20 hours, which is 90% of the cell cycle.

Define: mitosis, sister chromatids, centromere, cytokinesis, apoptosis

 * mitosis: duplication division that assures that all body cells have the diploid number and the same kinds of chromosomes as the cell that divides.
 * sister chromatids: the enlargement of a pair of chromosomes shows that in dividing cells each chromosome is composed of two identical parts, these parts are sister chromatids.
 * centromere: has the function of holding the chromatids together until a certain phase of mitosis when the centromere splits.
 * cytokinesis: is the division of the cytoplasm.
 * apoptosis: is the processed of programmed cell death.



Following mitosis, how does the chromosome number of the daughter cell compare with the chromosome number of the parent cell?

 * Because the parent cell and daughter cell have the same number and kinds of chromosomes, they are generally identical.

What are the phases of mitosis and what happens during each phase?

 * Prophase: chromosomes attach to spindle fibers.
 * Metaphase: chromosomes align at the equator.
 * Anaphase: chromatids separate, becoming chromosomes that move towards the poles.
 * Telophase: Nuclear envelopes form around chromosomes; cytokinesis begins.

How is the cytoplasm divided between the daughter cells following mitosis?

 * Following DNA replitcation, each chromosomeis duplicated.When the centromeres split, the sister chromatids, now called chromosomes, move into daughter nuclei.

Define: parent cell, daughter cell, diploid, centrosome, mitotic spindle, centrioles.

 * Parent Cell: cell that divides
 * Daughter Cell: new cells
 * Diploid: the complete number of chromosomes.
 * Centrosome: the microtubule organizing center of cell.
 * Mitotic Spindle: where the assembling of microtubles that make up spindle fibers.
 * Centrioles: Short cylinders of microtubules that are present in centrosomes.

What is the importance of mitosis and how is the process controlled?

 * Mitosis is duplication division. The nuclei of the two new cells have the same number and kinda of chromosomes as the cell that divides.