Transcript Cellular Reproduction

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