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The Cell Cycle● The regular sequence of growth and
division that cells undergo is known as the cell cycle.!
● Three main stages: !◦ Interphase!◦ Mitosis!◦ Cytokinesis
Stage 1: Interphase● During the first part of the cell cycle
known as interphase, the cell grows to mature size, makes a copy of its DNA, and prepares to divide into two cells.!
● DNA is spread out as chromatin
Stage 2: Mitosis
● Mitosis = the cell’s nucleus divides into 2 separate new nuclei.!
● One copy of DNA is distributed into 2 daughter cells.
Stage 2: Mitosis (Prophase)
● “Pro” means “first”: It is the first part of mitosis!
● What happens?!◦ DNA scrunches up into ! chromosomes!!◦ Nucleus dissolves
Stage 2: Mitosis (Metaphase)
● Chromosomes line up in the MIDDLE of the cell!
● Remember: !!Metaphase = Middle
Stage 2: Mitosis (Anaphase)
● Chromosomes are pulled to opposite ends of the cell by the centrioles with ropes called spindle fibers.!
● Remember: !!Anaphase = Apart
Stage 2: Mitosis (Telophase)
● The cell starts to form two new nuclei around the chromosomes!
● Chromosomes start to unwind back into chromatin!
● Remember:!◦ Telophase = Two Nuclei
Stage 3: Cytokinesis● Cytoplasm divides, distributing organelles into each of
the two new cells.!● Each new daughter cell has the same number of
chromosomes as the original parent cell.!● Remember:!● Cytokinesis = Cytoplasm splits
Cytokinesis in Animal Cells● In animal cells the cell membrane
pinches in creating two new cells, (each with ½ the organelles.)
Cytokinesis in Plant Cells● Form a cell plate across middle that
eventually turns into a new cell membrane, (new cell wall follows.)
Length of the Cell Cycle● Cells spend most of their time during the interphase
stage of the cell cycle.!● Mitosis only happens at the end to make new cells
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