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. Nucleic acids
B. Carbohydrates
C. Lipids
D. Proteins
Answer: Option D
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
Which catalyst is used in the decomposition of KClO₃ to prepare oxygen in the laboratory?
A. V₂O₅
B. Pt
C. MnO₂
D. Fe₂O₃

Correct Answer: Option C


Explanation:
Manganese dioxide (MnO₂) catalyzes the thermal decomposition of potassium chlorate: 2KClO₃ (heat, MnO₂) → 2KCl + 3O₂. Without MnO₂, decomposition requires higher temperature. MnO₂ is not consumed. Other catalysts can be used, but MnO₂ is standard in school labs. V₂O₅ is for SO₂ oxidation, Pt for various, Fe₂O₃ not typical. This is a simple preparation of oxygen.

This question belongs to: Science chemistry
Question #2
The chemical name of Vitamin C is:
A. Calciferol
B. Ascorbic acid
C. Tocopherol
D. Retinol

Correct Answer: Option B


Explanation:
Vitamin C is chemically known as ascorbic acid (C6H8O6). It is a vital nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters. Deficiency leads to scurvy. Retinol is Vitamin A, Calciferol is Vitamin D, and Tocopherol is Vitamin E.

This question belongs to: Science chemistry
Question #3
The scientist who first proposed that electrons move in specific orbits around the nucleus was:
A. J. J. Thomson
B. Ernest Rutherford
C. James Chadwick
D. Niels Bohr

Correct Answer: Option D


Explanation:
Niels Bohr in 1913 proposed the planetary model where electrons revolve in certain allowed circular orbits without radiating energy, with quantized angular momentum. Rutherford proposed the nuclear model but did not specify quantized orbits. Thomson gave plum pudding. Chadwick discovered neutron.

This question belongs to: Science chemistry