PCR amplification is evident during which phase of the amplification curve?

PCR amplification is evident during which phase of the amplification curve?

• A. Lag
• B. Log
• C. Plateau
• D. Declined

Answer: (B)

Amplification is most evident during the exponential (log) phase. In this stage, the target DNA is copied efficiently so the product roughly doubles each cycle, causing a sharp, steady rise in the fluorescence signal. This rapid, consistent growth is what real-time PCR uses to quantify the amount of starting material, and it contrasts with the lag phase (minimal early product) and the plateau phase (reagent limits slow amplification). A decline isn’t typical in standard PCR curves.

Amplification is most evident during the exponential (log) phase. In this stage, the target DNA is copied efficiently so the product roughly doubles each cycle, causing a sharp, steady rise in the fluorescence signal. This rapid, consistent growth is what real-time PCR uses to quantify the amount of starting material, and it contrasts with the lag phase (minimal early product) and the plateau phase (reagent limits slow amplification). A decline isn’t typical in standard PCR curves.