Question

Suppose the thermocycler is INCORRECTLY programmed to omit the 72∘C step in each cycle of an otherwise normal PCR run. Which of the following would most likely occur?

a) DNA denaturation would not occur
b) Primer annealing would not occur
c) DNA elongation would not occur
d) DNA amplification would still occur

Answer 1

Omitting the 72°C step in PCR would most likely prevent DNA elongation, as it is the optimal temperature for Taq DNA polymerase to function, leading to hindered DNA amplification.

Step-by-step explanation:

If a thermocycler is incorrectly programmed to omit the 72°C step in each cycle of a PCR run, c) DNA elongation would most likely not occur. The 72°C step is the optimal temperature for Taq DNA polymerase, the enzyme responsible for synthesizing new DNA strands by extending primers that are annealed to the template. Omitting this temperature step would prevent the enzyme from efficiently adding nucleotides to the primers, thereby hindering DNA amplification.