What is the primary function of DNA polymerase during replication?
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Mastering this deck provides a comprehensive understanding of DNA replication, enabling students to explain the process, identify key enzymes, and appreciate the molecular fidelity mechanisms essential for genetic stability—skills crucial for research, biotechnology, and medical sciences.
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| # | Front | Back | Hint |
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| 1 | What is the primary function of DNA polymerase during replication? |
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Explore the detailed steps of DNA replication, including enzyme functions, replication forks, and accuracy mechanisms.
DNA polymerase synthesizes a new DNA strand by adding nucleotides complementary to the template strand in the 5' to 3' direction. |
| Think of polymerase as the 'builder' adding building blocks. |
| 2 | At which site on the DNA does replication initiate? | Replication begins at specific locations called origins of replication, where the DNA unwinds to form replication forks. | Origin sites are like starting points on a map. |
| 3 | What enzyme unwinds the DNA double helix during replication? | Helicase unwinds the DNA strands by breaking hydrogen bonds between complementary bases, creating the replication fork. | Helicase 'hacks' into the helix to open it up. |
| 4 | Why are leading and lagging strands synthesized differently? | The leading strand is synthesized continuously in the 5' to 3' direction, whereas the lagging strand is synthesized discontinuously in Okazaki fragments due to the antiparallel nature of DNA. | Remember: continuous (leading) vs. discontinuous (lagging). |
| 5 | What role does primase play in DNA replication? | Primase synthesizes a short RNA primer that provides a starting point with a free 3' hydroxyl group for DNA polymerase to begin DNA synthesis. | Primase 'primes' the process by laying down primers. |
| 6 | Which enzyme removes RNA primers during replication? | DNA polymerase I removes RNA primers and replaces them with DNA nucleotides in prokaryotes; in eukaryotes, RNase H performs a similar function. | Think of polymerase I as the 'clean-up crew'. |
| 7 | What is the function of the sliding clamp during DNA replication? | The sliding clamp increases the processivity of DNA polymerase by holding it securely onto the DNA template, allowing rapid and efficient synthesis. | Clamp holds the polymerase in place like a seatbelt. |
| 8 | Describe the role of topoisomerase in DNA replication. | Topoisomerase relieves supercoiling ahead of the replication fork by creating transient cuts in the DNA, preventing tangling and supercoils. | Topoisomerase acts like a 'twist-reliever'. |
| 9 | What mechanism ensures high fidelity during DNA replication? | DNA polymerase has proofreading activity via its 3’ to 5’ exonuclease function, which removes incorrectly paired nucleotides to maintain accuracy. | Proofreading is like proofreading a typed document. |
| 10 | What is the significance of the replication fork structure? | The replication fork is the Y-shaped structure where the DNA double helix is unwound, enabling simultaneous synthesis of new strands on both templates. | Think of it as the 'front line' of replication. |
| 11 | How does DNA replication differ between prokaryotes and eukaryotes? | Prokaryotes have a single circular chromosome with a single origin of replication, while eukaryotes have multiple linear chromosomes with many origins, allowing faster replication. | Circular vs. linear chromosomes. |
| 12 | What is the purpose of telomerase in eukaryotic DNA replication? | Telomerase extends the telomeres at chromosome ends, preventing loss of genetic information during lagging strand synthesis and allowing cell division. | Think of telomerase as an 'end protector'. |
| 13 | Why is DNA replication considered semi-conservative? | Because each new DNA molecule consists of one original (parental) strand and one newly synthesized strand after replication. | Semi-conservative: one old, one new. |
| 14 | What is the role of single-strand binding proteins (SSBs)? | SSBs bind to unwound single DNA strands to prevent reannealing and protect them from degradation during replication. | SSBs act as 'stabilizers'. |
| 15 | Explain how the replication process ensures accuracy and reduces mutations. | Proofreading by DNA polymerase's exonuclease activity, mismatch repair systems, and high-fidelity polymerases work together to correct errors and maintain genetic integrity. | Multiple layers of quality control. |
| 16 | What is the function of DNA ligase in replication? | DNA ligase seals nicks between Okazaki fragments on the lagging strand, forming a continuous DNA strand. | Ligase 'glues' fragments together. |
| 17 | In what direction does DNA polymerase synthesize new DNA strands? | DNA polymerase synthesizes DNA in the 5' to 3' direction, adding nucleotides to the 3' hydroxyl group of the primer or previous nucleotide. | Remember: 5' to 3'. |
| 18 | What is the significance of the origin of replication in the cell cycle? | It initiates DNA replication, ensuring the entire genome is duplicated accurately and efficiently during the S phase. | Starting point for replication. |
| 19 | Name one enzyme involved in resolving DNA supercoiling during replication. | Topoisomerase relieves supercoiling ahead of the replication fork to facilitate smooth progression of the replication machinery. | Supercoiling 'twists' are managed by topoisomerase. |
| 20 | What is the role of accessory proteins in DNA replication? | Accessory proteins assist enzymes like DNA polymerase and helicase to stabilize the replication complex, enhance processivity, and coordinate replication activities. | They are the 'support crew' for replication enzymes. |
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