DNA replication

• What is the purpose of DNA replication?

  To produce cells for growth and repair
• How is DNA replicated?

  By using DNA helicase and DNA polymerase
• What role does DNA helicase play in replication?

  It unwinds the DNA double helix
• What is the function of DNA polymerase during replication?

  It catalyzes the joining of nucleotides
• What forms between the bases on the original and new DNA strands?

  Hydrogen bonds
• What is meant by base pairing in DNA replication?

  Specific bases pair with complementary bases
• What does each new DNA molecule contain?

  One original strand and one new strand
• What is the significance of the Watson-Crick model of DNA?

  • Describes the double helix structure
  • Explains base pairing rules
  • Provides insight into DNA replication
• What does semi-conservative replication mean?

  Each new DNA has one old and one new strand
• What was the result of the Meselson and Stahl experiment?

  DNA replicated semi-conservatively
• Why did the DNA settle in the middle during the experiment?

  It contained both heavy and light strands
• What did other scientists confirm about DNA replication after Meselson and Stahl's work?

  It is the universal method for all living things
• What happens to DNA when grown in heavy nitrogen broth?

  It incorporates heavy nitrogen into its structure
• What is the significance of centrifugation in the experiment?

  It separates DNA based on density
• Why were the results different in tubes A and B?

  Different nitrogen sources affected DNA density
• What is the first stage of DNA replication?

  Separation of the two DNA strands
• What occurs in the second stage of DNA replication?

  Single strands act as templates for new strands
• Name the two enzymes involved in DNA replication.

  DNA helicase and DNA polymerase
• What are the key steps in semi-conservative DNA replication?

  1. DNA helicase unwinds the double helix
  2. DNA polymerase synthesizes new strands
  3. Hydrogen bonds form between bases
  4. Each new DNA molecule has one old and one new strand