The cell cycle and mitosis

1
The cell cycle and mitosis
2

• Cells constantly reproduce exact duplicates of
  themselves. Why?
• Replacement
• Repair
• Growth

3

• Cells must make an exact copy of their DNA
• DNA is the blueprint of the cell and is found in
  the nucleus

4

• Cell growth and division happens in a series of
  recognizable steps called the Cell Cycle
• Rephrase what is the cell cycle?

5

• Cell cycle has three phases
• 1. Interphase
• Cell growth
• DNA replication occurs
• 2. Mitosis
• Nuclear division
• 2 daughter cells formed, each has identical DNA
• 3. Cytokinesis
• 2 identical cells

6
(No Transcript)
7

• DNA forms chromosomes-
• For most of the cells life, DNA is arranged
  loosely in the form of chromatin
• During mitosis DNA condenses into chromosomes

8
Interphase

• Longest phase
• Cell grows
• Chromosomes are duplicated- each duplicate is
  called a sister chromatid

9
Prophase

• Nuclear envelope breaks down
• Sister chromatids joined at centromere
• Centrioles move to opposite ends and the spindle
  fibers form between them

10
Metaphase

• Short
• Spindle fibers attach to centromere
• Sister chromatids line up along midline

11
Anaphase

• Sister chromatids are pulled apart by the spindle
  fibers

12
Telophase

• Final phase of mitosis- opposite of prophase
• Chromatids reach opposite poles
• Nuclear envelope reforms
• Chromosomes unwind

13
Cytokinesis

• Cytoplasm division
• Cytokinesis differs between plants and animals-
  why?