AP Biology Questions: DNA Replication Enzymes

📚 Quick Study Guide

🔍 DNA Replication: The process by which a DNA molecule is copied to produce two identical DNA molecules. 🧬 DNA Polymerase: Enzyme that synthesizes new DNA strands by adding nucleotides to the 3' end of a primer. It also proofreads the new strand. 🚧 Helicase: Enzyme that unwinds the DNA double helix at the replication fork. 🔗 Ligase: Enzyme that joins Okazaki fragments on the lagging strand. 🧪 Primase: Enzyme that synthesizes RNA primers, providing a starting point for DNA polymerase. ⚖️ Topoisomerase: Enzyme that relieves strain ahead of the replication fork by breaking, swiveling, and rejoining DNA strands. ✂️ Single-Strand Binding Proteins (SSBPs): Proteins that bind to single-stranded DNA to prevent it from re-forming a double helix.

🧪 Practice Quiz

1. Which enzyme is responsible for unwinding the DNA double helix at the replication fork?
   1. A. DNA Polymerase
   2. B. Helicase
   3. C. Ligase
   4. D. Primase
2. What is the function of DNA ligase in DNA replication?
   1. A. To synthesize RNA primers
   2. B. To unwind the DNA double helix
   3. C. To join Okazaki fragments
   4. D. To relieve strain ahead of the replication fork
3. Which enzyme synthesizes RNA primers during DNA replication?
   1. A. DNA Polymerase
   2. B. Helicase
   3. C. Ligase
   4. D. Primase
4. What is the role of single-strand binding proteins (SSBPs) during DNA replication?
   1. A. To unwind the DNA double helix
   2. B. To prevent the re-formation of the double helix
   3. C. To synthesize RNA primers
   4. D. To join Okazaki fragments
5. Which enzyme relieves strain ahead of the replication fork by breaking, swiveling, and rejoining DNA strands?
   1. A. DNA Polymerase
   2. B. Helicase
   3. C. Topoisomerase
   4. D. Ligase
6. What is the primary function of DNA polymerase?
   1. A. Unwinding the DNA double helix
   2. B. Synthesizing new DNA strands
   3. C. Joining Okazaki fragments
   4. D. Relieving strain ahead of the replication fork
7. Okazaki fragments are synthesized on which strand during DNA replication?
   1. A. Leading strand
   2. B. Lagging strand
   3. C. Both leading and lagging strands
   4. D. Neither leading nor lagging strands