Quick guide to semi-conservative DNA replication for high school exams

📚 Quick Study Guide

• 🧬 DNA Replication: The process by which a DNA molecule makes a copy of itself.
• 🧪 Semi-Conservative: Each new DNA molecule consists of one original strand and one newly synthesized strand.
• 🔑 Key Enzymes:
  • 🧬 *DNA Helicase:* Unwinds the DNA double helix.
  • 🧪 *DNA Polymerase:* Adds nucleotides to the growing DNA strand.
  • ✂️ *DNA Ligase:* Joins DNA fragments together.
• 📍 Origin of Replication: The specific site on the DNA molecule where replication begins.
• ➡️ Replication Fork: The point at which the DNA strands separate during replication.
• 🔄 Leading Strand: Synthesized continuously in the 5' to 3' direction.
• fragment.
• 💡 Base Pairing: Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C).

Practice Quiz

1. Which of the following best describes semi-conservative DNA replication?

   1. A. The original DNA molecule is completely conserved.
   2. B. The new DNA molecule consists of two newly synthesized strands.
   3. C. Each new DNA molecule contains one original and one new strand.
   4. D. The DNA molecule is broken down into smaller fragments.

2. What is the role of DNA helicase in DNA replication?

   1. A. To add nucleotides to the growing DNA strand.
   2. B. To join DNA fragments together.
   3. C. To unwind the DNA double helix.
   4. D. To proofread the newly synthesized DNA.

3. Which enzyme is responsible for adding nucleotides to the growing DNA strand?

   1. A. DNA ligase
   2. B. DNA helicase
   3. C. DNA polymerase
   4. D. RNA primase

4. What is the function of DNA ligase?

   1. A. To unwind the DNA double helix.
   2. B. To add nucleotides to the growing DNA strand.
   3. C. To join DNA fragments together.
   4. D. To initiate DNA replication.

5. In what direction is the leading strand synthesized?

   1. A. 3' to 5'
   2. B. 5' to 3'
   3. C. Both directions simultaneously
   4. D. It does not have a specific direction.

6. What are Okazaki fragments?

   1. A. Short DNA fragments synthesized on the leading strand.
   2. B. Short RNA sequences that initiate DNA replication.
   3. C. Short DNA fragments synthesized on the lagging strand.
   4. D. Enzymes that proofread the newly synthesized DNA.

7. Which base pairs with Adenine (A) in DNA?

   1. A. Guanine (G)
   2. B. Cytosine (C)
   3. C. Thymine (T)
   4. D. Uracil (U)