Cell Cycle

1
Cell Cycle
2
Interphase

• G1 rapid growth and metabolic activity
• S The chromosomes replicate
• cell structures that carry genetic info (DNA)
• G2 Centrioles replicate cell prepares for
  division
• organelles used to separate chromosomes

3
Interphase

• All cells go through it
• All human cells begin with 46 chromosomes
• 23 from mom and 23 from dad
• Thats 23 pairs of homologous chromosomes
• Chromosome 1 from mom codes for the same info as
  1 from dad
• At the end of interphase, each chromosome is
  double stranded
• Each strand is a chromatid

4
Mitosis OR Meiosis

• To separate chromosomes
• Mitosis somatic cells
• Meiosis gametic cells

5
Cytokinesis

• Cytoplasm divides
• The cell divides
• Two cells are made from one

6
Cellular Organization
Prokaryotic
Eukaryotic
Gametic Cells
Somatic Cells
Binary Fission
Mitosis
Meiosis
7
Binary Fission

• The circular chromosome is copied
• Two copies attach to the cell wall at different
  spots
• Cell membrane grows b/w chromosomes
• Cell pinches inward until two cells form

8
Eukaryotic Cells

• Two kinds of division, based on cells job
• Mitosis for body (somatic) cells
• skin, heart, nervous, blood
• Meiosis for sex (gametic) cells
• sperm or egg (ovum)

9
Mitosis

• Prophase chromosomes show
• Metaphase they line up single file on the
  metaphase plate
• Anaphase they separate at the centromere
• Telophase theyre encased in a nuclear
  membrane they begin to unwind
• RESULT two cells with identical genetics

10
Meiosis

• Pro I chromosomes pair up in homologous pairs
  forming tetrads so crossing over can occur

11
Meiosis

• Metaphase I they line up on the metaphase plate
  in tetrads
• Anaphase I homologous chromosomes separate

12
Meiosis

• Telophase I similar to mitosis
• Cells then go through another interphase without
  replicating DNA
• Meiosis II (with Pro II, Met II, Ana II, Telo II)
  is the same as Mitosis
• RESULT 4 cells with different genetic
  information

13
Mitosis v. Meiosis

• http//library.thinkquest.org/C004535/mitosis_vs_m
  eiosis.html
• Mitosis cells are Diploid (2N) all chromosomes
  are in pairs
• Meiosis cells are Haploid (N) all chromosomes
  are in singles