Cellular Reproduction Mitosis and Meiosis
Jan 18, 2016
Cellular Reproduction
Mitosis and Meiosis
Cellular Reproduction
• All organisms grow– From 1 billions of
cells– They divide from one
to two cells•Parent cell
daughter cells
Cells Alive
Why reproduce?
Asexual reproduction
•New cell identical to parent–Only ONE parent–Bacteria and Amoeba
• Mitosis = asexual reproduction
– Asexual reproduction – budding, binary fission
– Regeneration - starfish– Parthenogenesis – honey bees (new
generation without fertilization
Chromosomes• Made of DNA
– Deoxyribo Nucleic Acid
• Contain genes– Basic unit of heredity
• You have 46 chromosomes in all of your cells– 2 sets of 23
• Diploid number
Cell Cycle
Cell cycle
• Process that organizes, divides, and replicates the cell’s chromosomes
• Life of the cell until it divides
• I Play Music At The Club
Interphase
– Cell Grows– Duplicates DNA– Grows some more
Mitosis
1. Prophase• Chromosomes coil• Nuclear membrane disappears• Spindle fibers form
• 2. Metaphase• Chromosomes line up in the center of the cell
3. Anaphase• Chromosomes pulled apart toward the poles of
the cell
4. Telophase• Cell membrane pinches to form two cells
Cytokinesis
– Division of the cytoplasm– 2 new cells fully formed
•Identical to starting mother cell
Meiosis
• Process of cell division that reduces the chromosome number in half– 46 23
– How eggs and sperm are produced• Sex cells = gametes
• Split into two parts– Meiosis 1 and Meiosis 2– Similar to mitosis
End result of Meiosis
• 4 daughter cells• NOT identical to mother cell• Genetic diversity
Comparison Mitosis & Meiosis
• Mitosis– Done by somatic
cells– 1 cell division– 2 daughter cells
produced– Genetic info stays
the same– I Play Music At The
Club
• Meiosis– Done by gamete
producing cells– 2 cell divisions– 4 daughter cells
produced– Genetic info
changes– I Play Music At The
Club, Play Music At The Club
The “F” word• Gametes reunite in Fertilization
– the chromosome number returns to the starting number
– But, since any sperm can unite with any egg, who knows what you will get?!•Sexual reproduction leads to genetic
diversity