1. Cell Division
Chapter 3 Section 5

2. Cell Cycle
The regular sequence of growth and division that cells undergo
Cell grows
Prepares for division
Divides into two new cells, “daughter cells”
Three main stages:
Interphase
Mitosis
cytokinesis

3. Stage 1: Interphase Period before cell division
The cell grows to full size
Replicates
Makes an EXACT copy of its DNA in its nucleus
Each daughter cell must have a complete set of DNA to survive
End of replication, cell contains two identical sets of DNA
Prepares to divide

4. Stage 2: Mitosis Mitosis 4 Parts of Mitosis
The second stage of the cell cycle
Cell’s nucleus divides into two new nuclei
One copy of the DNA is distributed into each of the two daughter cells
4 Parts of Mitosis
Prophase
Metaphase
Anaphase
Telophase

5. 4 Parts of Mitosis Prophase
Threadlike chromatin in the nucleus condenses to form double-rod structure called chromosomes
Each chromosome has two rods, due to replication
Each identical rod in a chromosome is called a chromatid
Two chromatids are held together by a centromere

6. 4 Parts of Mitosis Metaphase
The chromosomes line up at the center of the cell
Each chromosome attaches to a spindle fiber at its centromere

7. 4 Parts of Mitosis Anaphase The centromeres split
The chromatids separate by spindle fibers (go to opposite ends of the cell)

8. 4 Parts of Mitosis Telophase
Chromosomes begin to stretch out, lose rodlike appearance
Nuclear envelope forms around each region of chromosomes

9. Stage 3: Cytokinesis Cytokinesis
Final stage of the cell cylce
The cytoplasm divides
Organelles are distributed into each of the two new cells
The cell will then enter interphase… and the cycle begins again.
Cytokinesis in Animal Cells: cell membrane squeezes together
Cytokinesis in Plant Cells: cell wall cannot squeeze together, a cell plate forms that gradually will develop into the cell membrane

10. The Structure of DNA Looks like a twister ladder, or spiral staircase
The sides of the ladder are made up of
Deoxyribose (sugar)
Phosphate
Each rung of the ladder is made up of a pair of molecules called nitrogen bases
Adenine (A) Thymine (T)
Guanine (G)  Cytosine (C)

11. The Replication Process
The two sides of the DNA molecule unzip and separate
Nitrogen bases floating in nucleus pair up with the bases on each half of the DNA molecule
New bases attach, two new DNA molecules form