Which of the following is an example of a coenzyme? MCQ with Answer and Explanation

Which of the following is an example of a coenzyme?
A. Collagen
B. Hemoglobin
C. NAD⁺
D. Pepsin
Answer: Option C
Solution (By JKExamLibrary)
NAD⁺ (nicotinamide adenine dinucleotide) is a coenzyme derived from vitamin B₃, serving as an electron carrier in redox reactions. Pepsin is an enzyme, collagen a structural protein, hemoglobin a transport protein. Coenzymes are organic non-protein molecules that assist enzymes.

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Practice More Biology Questions

Question #1
Which of the following diseases is vector-borne?
A. Tetanus
B. Common cold
C. Typhoid
D. Plague

Correct Answer: Option D


Explanation:
Plague is caused by Yersinia pestis and transmitted to humans by the bite of infected fleas (from rodents), thus vector-borne. Common cold is airborne, typhoid is water/food-borne, tetanus enters through wounds from soil. Other vector-borne diseases include malaria (mosquito), dengue (mosquito), Lyme disease (tick).

This question belongs to: Science Biology
Question #2
The human chromosome number (2n) is:
A. 23
B. 48
C. 46
D. 44

Correct Answer: Option C


Explanation:
Humans have 46 chromosomes in somatic cells (22 pairs of autosomes and one pair of sex chromosomes). Gametes have 23 chromosomes.

This question belongs to: Science Biology
Question #3
Which of the following is the correct sequence of taxonomic hierarchy from lowest to highest?
A. Species → Genus → Family → Order → Class → Phylum → Kingdom
B. Species → Family → Genus → Order → Class → Phylum → Kingdom
C. Genus → Species → Family → Order → Class → Phylum → Kingdom
D. Species → Genus → Order → Family → Class → Phylum → Kingdom

Correct Answer: Option A


Explanation:
The correct taxonomic hierarchy in ascending order is: Species (lowest) → Genus → Family → Order → Class → Phylum (or Division in plants) → Kingdom (highest). Some classifications add Domain above Kingdom. This system groups organisms based on shared characteristics. Binomial nomenclature uses Genus and Species. Option A correctly places Family before Order.

This question belongs to: Science Biology