4.2 DNA Replication

• What is the purpose of DNA replication?

  Create identical DNA copies
• Which enzyme separates the DNA strands during replication?

  Helicase
• The semi-conservative model ensures each new DNA molecule has one original strand.


  True
• DNA replication is a semi-conservative process.
• Match the replication model with its description:

  Semi-conservative ↔️ One old and one new strand

  Conservative ↔️ One new and one old molecule

  Dispersive ↔️ New and old DNA mixed
• Which enzyme synthesizes RNA primers during DNA replication?

  Primase
• The process of DNA replication is semi-conservative
• DNA Polymerase adds nucleotides
• What are the steps in DNA replication?

  1️⃣ Unwinding of the DNA helix by helicase

  2️⃣ Base pairing with complementary nucleotides

  3️⃣ Synthesis of new DNA strands by DNA polymerase
• In semi-conservative replication, each new DNA molecule contains one original and one new strand.


  True
• Helicase unwinds the DNA helix.
• What are the steps in the initiation phase of DNA replication?

  1️⃣ Helicase unwinds DNA at the origin

  2️⃣ Primase synthesizes RNA primers
• DNA replication ensures accurate and efficient duplication of genetic material.


  True
• Primase provides a starting point for DNA polymerase during replication.


  True
• What are Okazaki fragments joined by to complete the lagging strand?

  Ligase
• What is the key characteristic of semi-conservative replication?

  One old, one new strand
• What is the role of primase in the initiation phase of DNA replication?

  Synthesizes RNA primers
• What happens to DNA polymerase in the termination phase of DNA replication?

  Detaches from DNA
• Primase synthesizes RNA primers
• Helicase creates a replication fork
• The leading strand is synthesized continuously from 5' to 3' towards the replication fork
• Steps in DNA replication

  1️⃣ Unwinding DNA helix by helicase

  2️⃣ Base pairing with complementary nucleotides by DNA polymerase

  3️⃣ Synthesis of new strands by DNA polymerase
• Match the enzyme with its function:

  Helicase ↔️ Unwinds DNA helix

  DNA Polymerase ↔️ Adds nucleotides to DNA

  Ligase ↔️ Joins DNA fragments

  Primase ↔️ Synthesizes RNA primers
• Steps in the elongation phase of DNA replication

  1️⃣ Continuous synthesis of leading strand by DNA polymerase

  2️⃣ Discontinuous synthesis of lagging strand as Okazaki fragments

  3️⃣ Joining of Okazaki fragments by ligase
• DNA replication begins with the unwinding of the DNA helix by helicase.

  True
• Why is DNA replication essential for cell division?

  Ensures accurate genetic information
• Which replication model involves one new DNA molecule with both new strands and one entirely old molecule?

  Conservative
• DNA polymerase adds nucleotides to the growing DNA strand.


  True
• What is the function of ligase in DNA replication?

  Joins DNA fragments
• Which enzymes are involved in the initiation phase of DNA replication?

  Helicase and primase
• What does DNA polymerase add during the elongation phase of replication?

  Nucleotides
• DNA replication is a semi-conservative process.

  True
• In conservative replication, one new molecule has all new strands, and one has all old strands
• Helicase creates a replication fork at the origin of replication.


  True
• The semi-conservative nature of DNA replication reduces the risk of mutation