1. BIOLOGY Unit 4 Notes: Cell Division Basics & The Cell Cycle

2. (1) What is Cell Division?
Processes cells use to make copies of themselves.
Single Celled organisms can use it to reproduce.
Types of Division:
Mitosis
Meiosis

3. (2) Why Do Cells Divide?
Grow (make an organism larger and more complex)
Repair (tissues that were damaged)
Replace (lost / broken down cells)
Reproduce (to make more cells or organisms)

5. (4) The Cell Cycle
The cycle used to cells to prepare for cell division:
Makes copies of organelles.
Doubles the size of the cell.
Checks DNA for errors.
Completes cell division after preparation.

6. (5) Cell Cycle Diagram Interphase: G1 S G2 G1 PHASE G1 CkPt M PHASE G2
S PHASE
G2 PHASE

7. (6) Cell Cycle Stages G1 Phase = 1st Growth Phase
Cell copies organelles and increases size.
G1 Check Point Cell Makes sure cell is growing properly.
S Phase = DNA Synthesis Phase
Cell copies DNA
G2 Phase = 2nd Growth Phase
Cell continues to copy organelles and increase size.
G2 Check Point Cell makes sure DNA was copied properly.
M Phase = Mitosis or Meiosis Phase
Cell actually divides.

9. (7) Cancer & The Cell Cycle
If cells do not accurately check for errors during the G1 or G2 check points, defective or mutated cells will begin dividing in the organism.
Cancer:
Malfunctioning cells which divide and grow uncontrollably.