A researcher measures the rate of starch digestion by amylase at pH 2, 7, and 10. At which pH would the rate be greatest, and why?

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Question

A researcher measures the rate of starch digestion by amylase at pH 2, 7, and 10. At which pH would the rate be greatest, and why?

Accepted Answer

pH 7, because this is close to the optimum pH for salivary amylase — Salivary amylase has an optimum pH of approximately 7 (neutral), at which the active site shape is most complementary to the starch substrate. At pH 2, the highly acidic conditions alter the shape of the active site, denaturing the enzyme and greatly reducing activity. At pH 10, the alkaline environment also distorts the active site, reducing reaction rate.

Answer

pH 2, because amylase works fastest in the stomach environment

Answer

pH 7, because this is close to the optimum pH for salivary amylase

Answer

pH 10, because alkaline conditions increase enzyme activity overall

Answer

pH 2, because acid conditions denature amylase optimally

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