Question

Enzyme catalyzed reactions are affected by various changes in the reaction environment. Which of the following changes can affect an enzyme catalyzed reaction?
I. A change in temperature
II. A change in pH
III. A change in salinity

• A. I only
• B. II only
• C. I and II only
• D. I and III only
• E. I, II, and II

Answer 1

The correct option is E I, II, and II

Many factors affect the activity of enzyme like:

I. Temperature: Enzyme functions best at an optimum temperature of 20-40° C . The enzyme activity decreases with the slight decrease or increase from this optimum temperature range. A rise of 10° C in temperature causes the activity of the enzyme to be doubled. However, at very high temperature enzyme activity decreases because denaturation of proteins occurs.

II. pH: The pH range is 6-7.05 at which maximum. For most enzymes, the effective pH range is 4-9. Below this range, denaturation of enzymes occurs.

III Ionic concentration: Enzyme activity is affected by the concentration of ions especially hydrogen ions because each molecule of H⁺ (in slightly alkaline solution) and ‎OH⁻ ions (in slightly acidic medium). Thus, enzymes are capable of ionising either as an acid or as a base depending upon the acidity of external solution.

Hence all the options are correct.

So, the correct answer is 'I, II and III'.