1. The Cell Cycle

2. The Cell Cycle
Cell Cycle = A repeating sequence of cell growth and division during the life of a cell.
Cell division in eukaryotes = more complex due to organelles and a nucleus.

3. Five Stages of the Cell Cycle
Interphase:
G1 - primary growth phase
S – synthesis; DNA replicated
G2 - secondary growth phase
Mitotic phase
M - mitosis
C - cytokinesis

4. Cell Cycle

5. Interphase - G1 Stage 1st growth stage after cell division
Cells mature by making more cytoplasm & organelles
Cell carries on its normal metabolic activities

6. Two identical copies of DNA are made
Interphase – S Stage
Synthesis stage
DNA (chromosomes) copied
Two identical copies of DNA are made
Original DNA

7. Keeping Cells Identical
The instructions for making cell parts are encoded in the DNA, so each new cell must get a complete set of the DNA molecules

8. Eukaryotic Chromosomes
All eukaryotic cells store genetic info in chromosomes
Most eukaryotes have between 10 and 50 chromosomes in their body cells
Human body cells have 46 chromosomes (23 pairs)

9. Eukaryotic Chromosomes
Each chromosome is made of tightly coiled DNA
Chromatin is the relaxed form of DNA in a cell’s nucleus
DNA can only be seen when highly coiled in chromosomes
Chromatin: the relaxed form of DNA in the cell’s nucleus

10. Chromosomes in Dividing Cells
Duplicated chromosomes are called sister chromatids
Sister chromatids are held together by the centromere
Called Sister Chromatids

11. Sister Chromatids result from the S phase!
After S Phase
Before S Phase

12. Interphase – G2 Stage 2nd Growth Stage Cell prepares for division
All cell structures needed for division are made (ex: centrioles)
Additional organelles & proteins are made

13. Cells prepare for Division Cell Divides into Identical cells
Sketch the Cell Cycle
DNA Copied
Cells prepare for Division
Cells Mature
Daughter Cells
Cell Divides into Identical cells