Lecture 8 - Cancer - Mitosis Gone Wrong

• • Cancer is a group of cells that come from uncontrolled cell division.
• • Some cancers run in families while others are caused by things in the environment. Like poor lifestyle choices.
• • Cancer can even happen in cats, dogs, fish, even plants
• • Tumor: When cells grow uncontrollably and form a mass of cells.
• Benign Tumor: a tumor that is not cancerous because it has no affect on surrounding cells. 
• Malignant Tumor: a tumor is cancerous because it interferes with functioning of surrounding cells.
• Sometimes Cancer cells can break away from the tumor and travel to a different part of the body… This is called ~ Metastasis
• Abnormal Meiosis

  • Errors during meiosis can occur during “Crossing Over” or/and “Independent Assortment”
  • This can change: 

  1. The number of chromosomes or 
  2. Changes the chromosomes structure!   
• 1. Structural Errors

  • During cross over chemical bonds that hold the DNA together in chromosomes are broken and reformed. This causes Chromosomes Structural errors.
• 1. Structural Errors

  • A. Deletion: a piece of DNA is deleted from chromosome
• 1. Structural Errors

  • B. Duplication: a section of DNA appears 2-3x
• 1. Structural Errors

  • C. Inversion: a section of DNA is inverted
• 1. Structural Errors

  • D. Translocation: a segment of DNA becomes attached to a different chromosome 
• 1. Structural Errors

  • E. Insertion: a piece of DNA is inserted into the chromosome
• 1. Structural Errors

  • F. Base pair substitution: base pairs switch locations
• 2. Chromosome #Errors

  • Sometimes homologous chromosome pairs or sister chromatids do no separate as they should during meiosis ~ called non-disjunction.
  • This would occur during Anaphase I or II
  • As a result gametes produced have too many or few chromosomes.
• • The loss of a chromosome is called ~ Monosomy 
• • The gain of an extra chromosomes is called ~ Trisomy