AP BIOLOGY

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BIOCHEMISTRY

ENZYMES AND METABOLISM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The enzyme activity is influenced by the pH of the surrounding solution. Generally, all enzymes react most effectively at their optimal pH.* Most enzymes are most active in the range of between pH ____ For example, the salivary amylase works at pH 6.8.* However, there are some exceptions. For example, the pepsin enzymes in the stomach act at the optimal pH range of between 1.5 and 2.5. The trypsin enzyme in the duodenum, on the other hand, only works well in an alkaline medium, at a pH of around 8.5
A
6 to 8
B
7 to 9
Explanation: 

Detailed explanation-1: -Enzyme activity is at its maximum value at the optimum pH. As the pH value is increased above or decreased below the optimum pH the enzyme activity decreases.

Detailed explanation-2: -Changing the pH will affect the charges on the amino acid molecules. Amino acids that attracted each other may no longer be. Again, the shape of the enzyme, along with its active site, will change. Extremes of pH also denature enzymes.

Detailed explanation-3: -In general, an enzyme has an optimum pH. Although most enzymes remain high activity in the pH range between 6 and 8, some specific enzymes work well only in extremely acidic (i.e. pH <5.0) or alkaline (i.e. pH >9.0) conditions.

Detailed explanation-4: -At lower temperatures, the enzyme salivary amylase is deactivated and at higher temperatures, the enzyme is denaturated. Therefore, more time will be taken by enzyme to digest the starch at lower and higher temperatures. At 37° C, the enzyme is most active, hence, takes less time to digest the starch.

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