DNA replication: enzymes and proofreading

What you’ll practice

Sharpen your genetics fundamentals by identifying which enzyme does what at each stage of replication, and by explaining how fidelity is maintained through proofreading and repair.

Expect questions that connect concepts (leading vs lagging strand, Okazaki fragments, clamp loading, exonuclease activity) rather than isolated definitions.

Quiz format and difficulty

Every question has 4 options and there’s no timer, so you can reason through mechanisms without rushing.

Choose your preferred question count and a difficulty setting before you start; the “Mixed” balance blends easier recall items with scenario-style questions that test application.

Common pitfalls to avoid

Many mistakes come from mixing up similar-sounding roles (e.g., primase vs polymerase, ligase vs topoisomerase) or confusing proofreading with mismatch repair.

Pay close attention to directionality (5′→3′ synthesis), which strand is continuous, and when RNA primers are removed and replaced.

Tips for scoring higher

• Match each enzyme to its specific job (unwinding, priming, extending, sealing, relieving supercoils)
• Track strand direction and where Okazaki fragments form
• Separate proofreading (3′→5′ exonuclease) from post-replication mismatch repair
• Watch for prokaryote vs eukaryote differences in polymerases and accessory proteins
• Use process-of-elimination on close options by checking timing and location in the fork