The Cell cycle

1
The Cell cycle Cell division Mitosis

• How the cell in the body replicate

2
Cell Life Cycle

• Each cell has a life cycle
• The cell grows
• When it gets too big it prepares to divide
• When the cell divides its genetic material, it
  is called Mitosis
• When the cells split, it is called cytokinesis

3
Interphase

• This is the longest part of the cells cycle
• G1 phase growth
• S phase DNA replication
• Sister chromatids are formed
• G2 phase- prepare for Mitosis

4
Cell Division

• All cells come from existing cells. All living
  things create new cells by dividing.
• Cell division is different in prokaryotes and
  eukaryotes.

Prokaryotic cell reproducing
5
Cell Division in Prokaryotes

• Prokaryotes reproduce by binary fission.
• Steps in prokaryote binary fission
• DNA replicates
• Cell grows
• New cell wall develops
• Cell splits into two cells

Binary Fission
6
Cell division in Eukaryotic cells

• In Eukaryotic cells the nucleus divides before
  the rest of the cell does.
• The process of nuclear division is called
  mitosis.
• Mitosis is a multi- step process.

7
Mitosis

• After the DNA is replicated inside the nucleus,
  the chromosomes condense.
• Then the nuclear envelope dissolves.
• Chromosomes are lined up as sister chromatids in
  the center of the cell, with the centromere
  attached to a spindle structure.

8
Mitosis continued

• The sister chromatids separate into individual
  chromosomes
• Each moves to opposite sides of the cell, pulled
  by the fibers of the spindle.

9
Cytokinesis

• Each side of the cell now has identical DNA.
• When the membrane pinches in during
  cytokinesis, each daughter cell will have half
  the cytoplasm and organelles of the original cell.

10
Control of cell Division

• The cell has checkpoints to insure cell division
  goes well.
• G1 checkpoint if the cell is large and healthy,
  it will divide
• G2 checkpoint checks that the DNA was copied
  correctly
• Mitosis checkpoint to make sure genetic material
  was divided correctly.

11
Cancer

• If one of the proteins that monitors cell growth
  is not working properly (usually because of a
  mutation in the genetic code) then the cell will
  divide uncontrollably. This is cancer.

12
Write a one paragraph summary of the cell cycle
and cell division, explain why these are
important and what happens if something goes
wrong.