Create two identical cells from one cell Purposes: Create a new organism Growth and Repair

Binary Fission Single Circular chromosome is replicated Cell doubles in size Cell divides with one copy of chromosome in cell

Chromosome = two sections of identical DNA joined by a centromere Sister Chromatids = 2 identical halves of a chromosome. When separated chromatids = chromsomes

Cell cycle = series of events that cells go through as they grow and divide Begins and ends with formation of identical cells What do cells need to do before they can divide? Grow Replicate DNA

Two main phases – Interphase and M phase Interphase is when the cell is not actively dividing Longest phase broken into 3 stages: G1, S, G2

G1 = First growth phase Cell grows and carries out cell functions Cell creates RNA proteins and organelles Extended G1 phase (G0 phase) = no replication Nerves, roots, stems

S = Synthesis DNA is replicated, cell now has two copies DNA *Each chromosome is copied. The new copy is joined to the old copy. Identical copies = sister chromatids. Together they form a chromosome.

G2 = Second Growth Phase Cell finishes preparation for division Protein RNA and macromolecules are made 2x as much DNA in nucleus

M phase = Division Division of the nucleus Followed by division of the cytoplasm (cytokinesis) Two cells are created from 1 cell Shortest phase

Diagram and label the phases of Mitosis for a cell with 4 Chromosomes.