Practice question

Exponential amplification follows 2^n where n is cycle number. Typically 30 to 40 cycles generate 10⁹-fold amplification, converting trace template into detectable product visible on agarose gel. Fewer than 25 cycles may produce insufficient yield, especially for low-copy targets. Beyond 40 cycles, reaction reaches plateau due to depletion of dNTPs, primers, polymerase inactivation, and accumulation of inhibitors, increasing risk of non-specific products, primer-dimers, and background smearing. Therefore 25-35 cycles for abundant templates and 30-40 cycles for rare templates balances sensitivity with specificity in analytical PCR.