Download BIOL-Cell reproduction

Ch 7-1 Cellular Reproduction
•Interphase & Mitosis make up Cell Cycle (pg 174)
•The mitotic (M) phase of the cell cycle alternates
with the much longer interphase.
•The M phase includes mitosis
and cytokinesis.
•Interphase accounts
for 90% of the cell cycle.
Terms for the hereditary material (DNA) found in the
nucleus.
Chromatin—dense mass of material within the
nucleus; composed of individual chromosomes
Chromosomes—structure that carries the genes;
composed of protein & DNA
Chromatid—each individual strand of the double
stranded chromosome resulting from replication in
Prophase.
Centromere—point at which sister chromatids are
attached
*DNA, Protein spool, Chromatin, & Chromosomes
(Illustrations on pg 173)
The Cell Cycle
Interphase—(resting stage)
• Not a part of mitosis
• Cell grows & carries on all life activities
• DNA & Chromosomes replicate; producing a 2nd
set of chromosomes.
• Interphase has three subphases:
– the G1 phase (“first gap”) centered on growth,
– the S phase (“synthesis”) when the chromosomes are
copied,
– the G2 phase (“second gap”) where the cell completes
preparations for cell division,
• Mitosis (M)—the cell divides thru the
process by which chromosomes are
duplicated & distributed to daughter nuclei;
each daughter nucleus carries the same
set of genetic information as the parent
nucleus.
• There are four stages of Mitosis!
– Prophase
– Metaphase
– Anaphase
– Telophase
Prophase
• Chromosomes shorten & thicken becoming
visible
• Spindle fibers & asters form
• Centrioles move towards opposite poles
• By the end, the nucleus & nucleolus have
completely disappeared
Metaphase
• Paired chromatids (chromosomes) are lined up
at the equator.
• Microtubules are attached at the centromere.
Anaphase
• Centromere splits & the two sister chromatids
separate from one another & start moving
towards opposite poles…or sides of the cell.
Telophase
• Cytoplasm begins pinching in towards the center of the
cell…(cytokinesis)
• Spindle fibers & asters disappear
• Two new nuclei are formed
• Chromosomes become a mass of chromatin again
• The two daughter cells separate into two individual cells
• Animal Cell—pinching in a cell membrane to separate
the two cells
• Plant Cell—a cell plate forms which will eventually
become the cell wall…also they go thru mitosis without
the centrioles.