Cell Division:

1
Cell Division Mitosis and Cytokinesis
Pick up the handout And your W.R Quiz! Did you
take the quiz on Friday? Did you miss lab last
week?
2
Agenda 9/28/09 Learning Goal

• Agenda
• Go over quizzes (end of class)
• Begin discussing the nucleus and Cell Cycle
• Cell Cycle Mitosis

• Learning Goal
• To understand why a cell goes through a cycle and
  divides.
• Homework
• Cancer Article and questions due Wednesday
  9/30/09
• Excel Lab graph due Friday 10/2/09

3
What is the Cell Cycle? the life
cycle of a cell.

• Interphase The everyday phase, or time between
  cell divisions.
• G1 Growth, increase in size
• S Synthesis, copying DNA
• G2 Growth, preparing for division

• Cell Division Cell reproduction, making two
  identical cells.
• Mitosis Splitting the nucleus
• Cytokinesis Splitting the cytoplasm and other
  organelles

4
Some Background On Chromosomes

• During Interphase (most of the time), DNA is NOT
  wound and called chromatin.
• Chromosomes are just tightly wound up DNA strands.

5

• 46 per cell, 23 pairs
• Exception Sex Cells
• Each side of X is called a chromatid, or copied
  strand of DNA
• Disk holding two sides together is centromere

6
Mitosis
What is the end result? 2 exact copies
of 1 cell Why do cells undergo mitosis?
Growth, repair, reproduction
7
Interphase (before actual mitosis begins)
8
Prophase
9
Metaphase
10
Anaphase
11
Telophase
12
Cytokinesis The division of cytoplasm
organelles.
Plant vs. Animal