Cell Theory All living things are made of cells Cells are the basic functional unit of living things All cells come from preexisting cells

The Cell Cycle Cell Replication

The Cell Cycle Interphase – Growth Mitosis – Cell Division G1 Phase S Phase G2 Phase Mitosis – Cell Division Prophase Metaphase Anaphase Telophase

INTERPHASE G1 Phase (Gap 1 Phase) S Phase (Synthesis G2 (Gap 2 Phase) Cell grows and functions normally Produces more organelles Cytoplasm increases S Phase (Synthesis DNA Replication occurs G2 (Gap 2 Phase) Growth continues in preparation for mitosis

M PHASE (Mitosis) Division of the cell Reminder Chromosome: 2 sister chromatids held together (forms an “X) Chromatid: half a chromosome (single side of an “X” Centromere: holds sister chromatids together to form a chromosome

Prophase Nuclear envelope disappears DNA molecules coil to form chromosomes Centrioles migrate to opposite poles Spindle fibers appear

Metaphase Chromosomes align along equator Spindle fibers attach to centromere

Anaphase Centromere splits and pulls chromosomes apart into chromotids Chromotids move to opposite poles

Telophase Chromotids begin to unwind into loose strands of DNA Nuclear envelope reappears Spindle fibers disappear Cytokinesis: division of plasma and cell membrane

INTERPHASE Mitosis PROPHASE TELOPHASE METAPHASE ANAPHASE

Identify each of the stages of mitosis!

What about the FIRST cells of an organism? Fertilization and Meiosis