The term 'operon' in genetics refers to: MCQ with Answer and Explanation

The term 'operon' in genetics refers to:
A. A DNA repair mechanism
B. A viral DNA integrated into host genome
C. A set of linked genes regulated by a single promoter
D. A single gene with multiple functions
Answer: Option C
Solution (By JKSSB Mock Tests)
An operon is a functional unit of DNA in prokaryotes containing a cluster of genes under the control of a single promoter, transcribed as a single mRNA. Example: lac operon. It includes operator, promoter, and structural genes. Operons allow coordinate regulation. Eukaryotes generally lack operons.

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Practice More Biology Questions

Question #1
Consider the following statements about the nervous system:
1. Motor neurons carry impulses from the CNS to effectors.
2. Sensory neurons carry impulses from receptors to the CNS.
3. Interneurons are found only in the peripheral nervous system.
Which of the above is/are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1, 2, and 3
D. 1 and 3 only

Correct Answer: Option A


Explanation:
Motor (efferent) and sensory (afferent) neurons are correctly described. Interneurons are found in the CNS, not PNS. So 3 is incorrect.

This question belongs to: Science Biology
Question #2
The chemical reaction that links amino acids together is a:
A. Hydrolysis
B. Reduction
C. Dehydration synthesis
D. Oxidation

Correct Answer: Option C


Explanation:
Peptide bond formation is a condensation (dehydration synthesis) reaction where the carboxyl group of one amino acid reacts with the amino group of another, releasing a water molecule. Hydrolysis breaks bonds by adding water. Oxidation/reduction involve electron transfer. Dehydration synthesis builds polymers.

This question belongs to: Science Biology
Question #3
The plant cell wall is mainly composed of:
A. Cellulose
B. Lignin
C. Chitin
D. Peptidoglycan

Correct Answer: Option A


Explanation:
The primary cell wall of plants consists of cellulose microfibrils embedded in a matrix of hemicellulose and pectin. Secondary walls may contain lignin.

This question belongs to: Science Biology