Mitosis and the Cell Cycle Cell reproduction
Some Definitions n Somatic Cells – body cells – Produced through mitosis – Has 46 chromosomes (23 pairs) n Homolog – each member of a chromosome pair n Diploid (2 n) – total of 46 chromosomes in people – zygote & somatic cells n Haploid (n) – total of 23 chromosomes in people, gametes (sperm & egg)
The Cell Cycle n. The sequence of growth and division of a cell. n 95% of cell cycle in interphase n 5% of cell cycle in mitosis
Cell cycle
Interphase n Growth Stage 1 (G 1) – metabolic activity of the cell n Synthesis Stage (S) – metabolic activity of the cell, replication of DNA n Growth Stage 2 (G 2) – metabolic activity of the cell, prepare for division
Mitosis n. Happens in all cells n. Cell division process n 5 major stages
Prophase n Nuclear envelope disappears n Chromosomes condense – can see sister chromatids and centromere n Spindle forms
Metaphase n Chromosomes move to the equator of spindle n Each chromatid is attached to spindle with centromere
Anaphase n Centromeres split n Sister chromatids are pulled apart to opposite poles of the cell n Each chromatid is now a separate chromosome
Telophase n Nuclear envelopes (2) reform n Chromosomes begin to uncoil
Cytokinesis n Cytoplasm divides n Two new daughter cells are now separate