DNA Replication

• What is the first step in DNA replication?

  DNA gets split by an enzyme known as helicase
• How does the double helix structure of DNA open during replication?

  The double helix structure opens by the enzyme splitting it
• What does it mean that the two strands of DNA are complementary?

  One strand can serve as a template for the other strand
• Why must DNA be copied before a cell can divide?

  So that the two new cells will each have one copy of the DNA
• What happens to the original strand of DNA during replication?

  It serves as a template for the new complementary strands
• During which phase of the cell cycle does DNA replication occur?

  During the S phase
• What is the role of helicase in DNA replication?

  Helicase "unzips" the old strands of DNA
• What happens to the bonds during the unzipping of DNA?

  The hydrogen bonds between the strands break
• What is the primary enzyme involved in replicating both strands of DNA?

  DNA polymerase
• Where is helicase found during DNA replication?

  Helicase is found around the nucleus
• What does each new strand of DNA contain after replication?

  Each new strand has a complementary base pair sequence
• How many template strands are present in each new DNA strand after replication?


  Each new strand contains one original template strand
• What are the key enzymes involved in DNA replication and their functions?

  • Helicase: Unzips the DNA strands
  • DNA polymerase: Synthesizes new DNA strands using the original strands as templates
• What is the process of DNA replication in summary?

  1. DNA strands are unzipped by helicase.
  2. The original strands serve as templates.
  3. DNA polymerase synthesizes new complementary strands.
  4. Each new DNA molecule consists of one original and one new strand.
• DNA polymerase finds free floating nucleotide bases to attach to the seperate ones on the original DNA strand.
• Each new DNA strand is considered semi-conservative.
• Why are the new DNA strands considered semi-conservative?

  They each contain one of the original template strands. They are similar, not identical copies of the parent strand.