DNA Replication - Semi-Conservative Model - Unsolved Practice Set
Chapter: Molecular Basis of Inheritance | Topic: DNA Replication Semi Conservative Model
DNA REPLICATION - SEMI-CONSERVATIVE MODEL - UNSOLVED PRACTICE SET
Topic: DNA Replication Semi Conservative Model
Multiple Choice Questions
Q1. According to the semi-conservative model of DNA replication, each daughter DNA molecule consists of:
- Two newly synthesised strands
- One parental strand and one newly synthesised strand
- Two parental strands
- Only RNA strands
Q2. The enzyme responsible for unwinding the DNA double helix during replication is:
- DNA polymerase
- Helicase
- Ligase
- Primase
Q3. DNA polymerase synthesises new DNA strands in the direction of:
- 3' to 5' only
- 5' to 3' only
- Both directions simultaneously
- A random direction
Q4. Short fragments synthesised discontinuously on the lagging strand during DNA replication are called:
- Primers
- Okazaki fragments
- Nucleosomes
- Replication forks
Q5. The enzyme that joins Okazaki fragments together on the lagging strand is called:
- DNA polymerase
- Helicase
- DNA ligase
- RNA polymerase
Short Answer Questions
Q6. What does "semi-conservative" mean in the context of DNA replication?
Q7. Why is DNA replication described as occurring at a "replication fork"?
Q8. What is the role of primase in DNA replication?
Q9. Why is the lagging strand synthesised discontinuously, unlike the leading strand?
Long Answer Questions
Q10. Describe the process of DNA replication, explaining the roles of helicase, primase, DNA polymerase, and ligase.
Q11. Explain why one strand (the leading strand) is synthesised continuously while the other (the lagging strand) is synthesised in short fragments during replication.
APPLICATION / ANALYSIS
Q12. A biology student is asked to compare the semi-conservative, conservative, and dispersive models of DNA replication that were once proposed as possibilities. Explain what distinguishes the semi-conservative model from the other two, in terms of how parental and new DNA strands would be distributed.
Q13. If a cell undergoing replication has a defective ligase enzyme, predict what problem this would cause specifically on the lagging strand, and explain your reasoning based on how Okazaki fragments are normally processed.