1. 1. Notes on Cell Cycle 2. Lab: Cell Cycle 3. Video: Mitosis & nanotechnology (if time) Homework: Learning Goal: Describe the cell cycle and explain why it occurs.

2. What is the cell cycle? The life cycle consists of all the activities the cell does before it “dies”. So the cell cycle is the life cycle of the cell.

3. 1. Interphase – growth and normal metabolic activities. 2. Cell division – cell produces two identical daughter cells.

4. Phases of the Cell Cycle: Cell Division: Cell reproduction, making two identical cells. Two phases… 1.Mitosis: Splitting the nucleus 2.Cytokinesis: Splitting the cytoplasm and other organelles Interphase: The “everyday” phase, or time between cell divisions. Three phases… 1.G1: Growth, increase in size 2. S: Synthesis, copying DNA 3.G2: Growth, preparing for division

5. The Cell Cycle

6. What is the end result? 2 identical daughter cells that perform the same function as the parent cell Why do cell go through mitosis? To replace old cells (reproduction), repair damaged ones, & growth of new ones

7. Some Background On Chromosomes (nuclear contents) Chromosomes are tightly wound up DNA strands. During Interphase (most of the time), DNA is NOT wound up and is called chromatin. chromatinnucleosome

8. 46 per cell, 23 pairs Exception: Sex Cells Each side of X is called a chromatid (a copied strand of DNA) Disk holding two sides together is a centromere Chromosomes

9. Greatest Discoveries