1. Cellular Reproduction and Chromosomes
Cell Cycle, Mitosis

2. Cell Cycle
Cells reproduce through a continuous sequence of growth and division known as the cell cycle
Interphase – cells are making new molecules and DNA is copied in a process called DNA replication.
Interphase broken into 3 steps:
G1 – Gap 1 involves metabolic activities
S – Synthesis involves DNA replication
G2 – Gap 2 is preparation for cell division
M – Mitosis and Cell Division

3. Cell Cycle
Timing of each phase can vary among different types of cells.
Organ cell vs. skin cell
Parent cell divides to create two new daughter cells (somatic cells have 46 chromosomes)
Purpose of Mitosis
Growth
Regeneration of Damaged Tissue
Maintenance of the Body

4. Phases of Mitosis
Several events must happen to ensure that as a cell divides, the genetic material inside is properly shared between each new daughter cell.
Root tip cells are often looked at as they undergo mitosis frequently
Phase order: PMAT
Prophase
Metaphase
Anaphase
Telophase & Cytokinesis

5. Prestep!!!
INTERPHASE!
During this phase the cell grows, heals, and creates proteins in order to start the division process!
The cell duplicates it’s genetic material (called chromatin) and creates two identical sister chromatids, joined by an object known as a centromere.

6. Mitosis
Prophase
chromatin, which is DNA and proteins, condenses and becomes visible
Nuclear membrane and nucleolus disappear
Centrioles made up of microtubules migrate to opposite poles of the cell
Spindle fibres start to form between the two centrioles

7. Mitosis Metaphase Anaphase Spindle fibres attach to centromere
Chromosomes line up on the cell’s equator (equatorial plate)
Anaphase
Centromere splits and chromatids are pulled to opposite poles of the cell

8. Mitosis Telophase Cytokinesis Chromatids reach the two opposite poles
At this time each chromatid is considered a single non-replicated chromosome
Chromosomes unwind and become less visible
Cytokinesis
Actual cell division
Spindle fibres disappear, nucleolus reappears, nuclear membrane and in plant cells a new cell wall is formed