Download THE CELL CYCLE and MITOSIS Each time new cells are produced

THE CELL CYCLE and MITOSIS
Each time new cells are produced, there is a cycle it must go through. They are:
 Interphase (before mitosis)
 Prophase
 Metaphase
 Anaphase
 Telophase
 Cytokinesis (after mitosis)
INTERPHASE
 Time between divisions..
 The nucleolus is visible.
 Chromatin is uncoiled.
 Individual chromosomes are not yet visible
 Chromosomes replicate at the end of this phase.
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PROPHASE
 First stage of mitosis
 Sister chromatids: two identical copies of the same chromosome held together by a
centromere
 Centromere: holds the sister chromatids together
 Chromosomes grow shorter and thicker
 Nuclear envelope and nucleolus disappear
 Centrioles are replicated (found only in animal cells; form the spindle fibers)
 Spindle fibers begin to form (extend from centrioles to centrioles across the cell;
help to pull the sister chromatids apart)
METAPHASE
 The 2nd phase of mitosis
 The chromatid pairs line up along the center of the cell.
 Each sister chromatid is attached to its own spindle fiber.
ANAPHASE
 The 3rd phase of mitosis.
 The centromeres divide and the chromatid pairs split forming individual
chromosomes
 The spindle fibers contract pulling each chromosome toward their pole.
 This process continues until the chromosomes arrive at each pole.
 The nucleus reappears and the spindle fibers disappear.
TELOPHASE
 The 4th phase of mitosis.
 Chromosomes arrive at opposite poles.
 Spindle fibers disappear.
 Nuclear membrane forms around each set of chromosomes.
 Chromosomes uncoil and revert to chromatin.
 Nucleolus reforms inside each nucleus.
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CYTOKINESIS
The last part of the cell cycle.
The cytoplasm divides forming two cells.
The daughter cells are genetically identical to the parent cell, only smaller.
Animals:
 Cell membrane pinches in and produces two new cells
Plant:
 They cannot pinch in due to cell wall.
 A cell plate forms between the two daughter cells.
 Each daughter cell then gets its own cell wall.
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