1. Asexual Reproduction
Getting to the Details

2. Asexual Reproduction in Prokaryotes
Binary Fission
Prior to division, an exact copy of DNA is made
Each copy attaches to a different point on plasma membrane
Cell stretches out and pinches in two

3. Asexual Reproduction in Eukaryotes
The Cell Cycle or life cycle of cell can range from 16 hours to days, to a lifetime
Eukaryotic Cells are more complex, so process of cell division is more complicated

4. First Stage of Interphase
G1 - Gap 1 Begins at the end of cell division
This is the time for cell growth and activity
This stage can be extended if environmental factors are not favorable

5. Second Stage of Interphase
S - Synthisis
The DNA replicates or makes a copy of itself during this stage
Each chromosome now consists of two sister chromatids

6. Third Stage of Interphase
G2 – Gap 2
Centrioles replicate, and begin to separate
Centriole pairs produce centrosomes –spindle organizing centers
The nucleolus produces ribosomes for increasing protein synthesis needed for growth

7. Mitosis Begins: Prophase
Changes in the Nucleus:
Chromatin condenses to become visible
Sister chromatids join together at centromere
The Nucleolus disappears
Nuclear membrane begins to dissolve

8. Prophase Continued: Changes in the cytoplasm
Centrosomes move to opposite sides to the cell forming poles
Mitotic spindles grow out from the centrosomes
Each chromosome attaches to a spindle fiber microtubule
Chromosomes begin to move toward the middle of the cell

9. Metaphase The mitotic spindle is complete
Chromosomes are all lined up on the ‘metaphase plate’ at the middle of the cell
The sister chromatids face opposite poles.
Each member of the pair is attached to a spindle fiber heading in the opposite direction

10. Anaphase
Anaphase begins when the two centromeres of each chromosome come apart
The sister chromatids separate and are pulled by the spindle fiber to opposite poles
Each sister chromatid is now considered a complete daughter chromosome
The cell begins elongating

11. Telophase Telophase is roughly the reverse of prophase
Daughter nuclei appear at opposite poles as nuclear membrane forms around chromosomes
Chromatin uncoils so chromosomes no longer visible

12. More on Telophase Nucleoli reappear Mitotic Spindle disappears
Cell elongation continues
Mitosis is complete

13. Cytokinesis The cytoplasm divides equally
In animals, a cleavage furrow forms, pinching the cell in two
In plants, a cell plate forms between new cells, forming a cell wall

14. Mistakes in Mitosis
Cancer occurs when cell cycle regulation malfunctions
Cells divide rapidly, forming abnormal tissue or tumors
Current research is focusing on cell cycle regulation
Most chemotherapies work by disrupting cell division and the formation of the spindle fibers