Semi conservative DNA replication

• What is the method of DNA replication called?

  Semi-conservative replication
• Why must DNA be replicated during cell division?

  To ensure daughter cells receive identical DNA
• What does "semi" in semi-conservative replication refer to?

  Half of the DNA molecule is old
• What does "conserve" in semi-conservative replication imply?

  It can be used as a template
• What is the significance of semi-conservative replication for genetic information?

  It ensures genetic information remains unchanged
• What type of cells does a skin cell replicate into?

  Skin cells
• What type of cells do small intestine cells replicate into?

  Small intestine cells
• What are the steps of semi-conservative DNA replication?

  1. DNA helicase unwinds the DNA
  2. Hydrogen bonds between bases break
  3. Strands separate
  4. Each strand acts as a template
  5. New nucleotides pair with exposed bases
  6. DNA polymerase joins new nucleotides
• What enzyme unwinds the DNA during replication?

  DNA helicase
• What happens to hydrogen bonds during DNA replication?

  They are broken between complementary bases
• What role do new DNA nucleotides play in replication?

  They pair with exposed complementary bases
• What type of reaction does DNA polymerase perform to join nucleotides?

  Condensation reaction
• What type of bonds are formed between new nucleotides during replication?

  Phosphodiester bonds
• What does semi-conservative replication ensure about the new DNA molecules?

  Each contains an original and a new strand
• What are the key terms associated with DNA replication?

  • Semi-conservative
  • DNA helicase
  • Unwinds and unzips strands
  • Breaking hydrogen bonds
  • Separate strands
  • Template
  • New nucleotides
• Watson-crick model
• What model of DNA replication should you evaluate?

  Watson-Crick model
• What was the purpose of the Meselson-Stahl experiment?

  To show DNA was replicated by semi-conservatively
• What isotopes of nitrogen were used in the Meselson-Stahl experiment?

  N14 and N15
• Why was N15 used in the experiment?

  It is a heavy nitrogen isotope
• What happens to bacteria grown in N15 when transferred to N14 medium?

  They use N14 in their DNA
• What does centrifugation reveal about the density of DNA?

  Denser material settles at the bottom
• What type of DNA was produced after one generation in N14 medium?

  14N15N (hybrid) DNA
• How many generations were the bacteria allowed to divide in the experiment?

  Three generations