Cell Tissue Organ Organ System Organism

**Cells must divide and create many cells in order for this process to occur

The Cell Cycle Interphase, Mitosis and Cytokinesis

G1 – (Organelles Duplicate)

G2 –

(Cell prepares to divide)

S – DNA synthesizes (also called duplicates or replicates)

Interphase (G1, S and G2)

** Cell grows

** Organelles duplicated (G1)**DNA synthesizes (S)** Only chromatin (uncoiled chromosomes) visible

** Majority of time for a cell is in this phase

• Carriers of genes• Some genes carry the

“instructions” for protein production

• Remember, chromosomes are duplicated during the S phase of Interphase prior to mitosis!

• You have 46 total chromosomes in the nucleus of most of your cells!!

**Four phases of mitosis (cell division) are:

**Anaphase

**Recall Mitosis Divides the nucleus, Cytokinesis Divides the Cytoplasm

**Telophase

** Duplicated chromosomes become visible

** A spindle, football shape structure that contains many fibers, moves to opposite poles

**Chromosomes line up in the MIDDLE of the cell ) its equator)

**Each chromatid is attached to a separate spindle fiber by its centromere (in the middle!!)

** Centromeres split pulling apart sister chromatids.** Chromatids move to opposite poles

** Chromosomes uncoil back into chromatin** Two nuclei appear

** In plants a cell plate forms between the 2 cells

** In animals a cleavage furrow forms (plants have a cell plate)

Animal Cell

** Two new identical daughter cells after

ONLY in animal cells

Only in PlantsOnly in Plants

**NO TRUE NUCLEUS!!! DNA replicates and the plasma membrane just pinches inward to form two new cells.