Enzymes are affected by pH and temperature because they are: MCQ with Answer and Explanation

Enzymes are affected by pH and temperature because they are:
A. Carbohydrates
B. Lipids
C. Proteins
D. Nucleic acids
Answer: Option C
Solution (By JKSSB Mock Tests)
Enzymes are proteins with complex three-dimensional structures maintained by hydrogen bonds, ionic bonds, and hydrophobic interactions. Extremes of pH or high temperature disrupt these bonds, causing denaturation (loss of structure and function). Each enzyme has an optimum pH and temperature. For example, pepsin works in acidic stomach, trypsin in alkaline intestine.

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Practice More chemistry Questions

Question #1
Assertion (A): Dry HCl gas does not change the color of dry litmus paper. Reason (R): Acids produce H⁺ ions only in the presence of water.
A. Both A and R are true but R is NOT the correct explanation of A.
B. A is true but R is false.
C. Both A and R are true and R is the correct explanation of A.
D. A is false but R is true.

Correct Answer: Option C


Explanation:
The acidic behavior of HCl is due to the presence of H⁺ (or H₃O⁺) ions, which are generated only when it dissolves in water. Without moisture, HCl doesn't dissociate to produce H⁺, so it doesn't change the color of dry litmus. Both statements are correct and R explains A.

This question belongs to: Science chemistry
Question #2
The process of converting a solid directly into vapor without passing through the liquid state is called:
A. Condensation
B. Evaporation
C. Distillation
D. Sublimation

Correct Answer: Option D


Explanation:
Sublimation is the direct transition from solid to gas phase. Examples: naphthalene, camphor, iodine, solid CO₂ (dry ice). Evaporation is liquid to gas; condensation is gas to liquid; distillation separates liquid mixtures based on boiling points.

This question belongs to: Science chemistry
Question #3
The extraction of aluminium is done by:
A. Electrolysis of molten alumina in cryolite
B. Thermite process
C. Reduction with aluminium
D. Reduction with carbon

Correct Answer: Option A


Explanation:
Aluminium is highly reactive; its oxide cannot be reduced by carbon. Hall-Héroult process electrolyzes alumina dissolved in molten cryolite (Na₃AlF₆) using carbon anodes.

This question belongs to: Science chemistry