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