Biology 130 Molecular Biology and Genetics

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Biology 130 Molecular Biology and Genetics
Kandinsky Several Circles
Chromosomes dividing during Cell division
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Biology 130 Molecular Biology and Genetics Knox
College Winter 2007   Instructors    
Christopher Thompson      Stuart
Allison                         SMC
B110                    SMC B210                  
       x7477                          
x7185                         email 
cthompso                 email  sallison   Lab
Coordinator  Leanne Lilly, SMC B113, x7386,
email  mlilly   Office Hours Thompson MWF
1030-12 Th 900-1230.  Allison  MWF 3rd  and
5th period   Lecture  SMAC A110 MWF 2nd
period       Lab  SMAC B121   Textbooks 
Campbell and Reece.  2005.  Biology 7th Ed. 
Benjamin Cummings.                       Ridley. 
2000.  Genome.  Perennial.                    
    Course Webpage  http//courses.knox.edu/bio1
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Cell Division

• Unicellular organisms
• Reproduce by cell division
• Multicellular organisms depend on cell division
  for
• Development from a fertilized cell
• Growth
• Repair
• The cell division process
• Is an integral part of the cell cycle

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• Cell division results in genetically identical
  daughter cells
• Cells duplicate their genetic material before
  they divide, ensuring that each daughter cell
  receives an exact copy of the genetic material,
  DNA
• A cells endowment of DNA, its genetic
  information,
• is called its genome
• The DNA molecules in a cell are packaged into
  chromosomes

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Chromosomes

• Eukaryotic chromosomes
• Consist of chromatin, a complex of DNA and
  protein that condenses during cell division
• In animals
• Somatic cells have two sets of chromosomes
• Gametes have one set of chromosomes
• In preparation for cell division
• DNA is replicated and the chromosomes condense

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Cell Division

• Eukaryotic cell division consists of
• Mitosis, the division of the nucleus
• Cytokinesis, the division of the cytoplasm
• In meiosis
• Sex cells are produced after a reduction in
  chromosome number

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The cell cycle consists of the mitotic phase and
interphase. Interphase can be broken down into
three phases G1, S, and G2.
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The Cell Cycle

• We typically divide interphase into three phases
  the G1 phase (for Gap 1), the S phase (for
  synthesis), and G2 phase (for gap 2).
• The cell only duplicates its chromosomes (DNA)
  during the S synthesis phase. Thus a cell grows
  (G1), continues to grow as it synthesizes DNA and
  duplicates chromosomes (S), grows more and
  completes preparations for cell division (G2) and
  then divides (M).
• Daughter cells then repeat the cycle
  potentially infinitely.

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Red spotted newt
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Hypothesis In this model a chromosome tracks
along a microtubule as the microtubule
depolymerizes at its kinetochore end,
releasing tubulin subunits.
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Bacterial cell division
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Dinoflagellate Diatom