1. Which enzyme is responsible for adding nucleotides to the new DNA strand?
2. DNA replication is described as:
3. The lagging strand is synthesized in:
4. What is the replication fork?
5. Which strand is synthesized continuously?
6. What role does DNA ligase play in replication?
7. What is the direction of DNA synthesis?
8. What are Okazaki fragments?
9. What type of bond connects the phosphate and sugar in the DNA backbone?
10. DNA replication in prokaryotes is:
11. Which enzyme relieves supercoiling during replication?
12. What is the role of telomerase?
13. Which enzyme removes RNA primers?
14. Which enzyme is responsible for unwinding the DNA helix?
15. What stabilizes single-stranded DNA during replication?
16. Which enzyme synthesizes the RNA primer?
17. What is the purpose of proofreading during replication?
18. What prevents DNA strands from reannealing during replication?
19. Replication starts at a specific site called the:
20. Which nucleotide pairs with thymine?
Topics Covered in DNA Replication MCQs
The following description outlines the major topics covered in the MCQs related to DNA replication:
1. Mechanism of DNA Replication
- Semi-Conservative Nature: DNA replication is described as semi-conservative, where each new DNA molecule consists of one parent strand and one newly synthesized strand.
- Direction of Synthesis: DNA synthesis occurs in the 5′ to 3′ direction, following the sequence on the template strand.
2. Key Enzymes in DNA Replication
- Helicase: Responsible for unwinding the DNA double helix to create replication forks.
- Primase: Synthesizes RNA primers, which provide a starting point for DNA synthesis.
- DNA Polymerase: Adds nucleotides to the growing DNA strand and removes RNA primers in some cases.
- Ligase: Joins Okazaki fragments on the lagging strand to create a continuous DNA strand.
- Topoisomerase: Relieves supercoiling stress ahead of the replication fork by cutting and rejoining DNA strands.
- Telomerase: Extends telomeres, protecting the ends of linear chromosomes from degradation.
3. Replication Fork and Strand Synthesis
- Replication Fork: A Y-shaped region where the DNA strands separate and replication occurs.
- Leading Strand vs. Lagging Strand: The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously in Okazaki fragments.
4. Key Features of DNA Structure
- Bonding: Covalent bonds connect the sugar and phosphate in the DNA backbone, while hydrogen bonds pair bases between strands.
- Base Pairing: Adenine pairs with thymine, and guanine pairs with cytosine in DNA.
5. Prokaryotic vs. Eukaryotic Replication
- Prokaryotic DNA Replication: Generally bidirectional, starting from a single origin of replication.
- Telomerase Role in Eukaryotes: Extends chromosome ends in eukaryotic cells to prevent loss of genetic material.
6. Additional Features and Quality Control
- Okazaki Fragments: Short DNA fragments on the lagging strand synthesized discontinuously.
- Single-Strand Binding Proteins: Stabilize single strands of DNA to prevent reannealing during replication.
- Proofreading: DNA polymerase performs proofreading to correct base-pairing errors, ensuring fidelity in replication.
