Q.14 Match the media component (Column I) with its role (Column II).
Column I Column II
P. Sucrose 1. Anti-foam agent
Q. Zinc chloride 2. Nitrogen source
R. Ammonium sulphate 3. Carbon source
S. Silicone oil 4. Trace element
(A) P-1, Q-2, R-3, S-4
(B) P-2, Q-1, R-3, S-4
(C) P-3, Q-2, R-4, S-1
(D) P-3, Q-4, R-2, S-1
Sucrose serves as a primary carbon source in microbial culture media, while other components like zinc chloride provide essential trace elements. Understanding their roles is key for GATE Biotechnology exam preparation.
Correct Answer
The correct matching is (D) P-3, Q-4, R-2, S-1. Sucrose (P) acts as the carbon source (3), zinc chloride (Q) supplies trace elements (4), ammonium sulphate (R) functions as the nitrogen source (2), and silicone oil (S) serves as the anti-foam agent (1).
Roles of Media Components
Sucrose provides readily available carbohydrates for energy and growth in fermentation media, commonly used for bacteria like E. coli. Ammonium sulphate delivers nitrogen for protein and nucleic acid synthesis, essential in synthetic media.
Zinc chloride supplies zinc as a trace element, supporting enzyme cofactors and metabolic processes in minimal quantities. Silicone oil prevents foam buildup in bioreactors during aeration, maintaining process efficiency.
Why Other Options Fail
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Option (A) P-1, Q-2, R-3, S-4: Incorrectly assigns sucrose as anti-foam (1) instead of carbon source, and mismatches others entirely.
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Option (B) P-2, Q-1, R-3, S-4: Wrongly places sucrose as nitrogen source (2) and zinc chloride as anti-foam (1).
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Option (C) P-3, Q-2, R-4, S-1: Sucrose correctly matches carbon (3) and silicone oil anti-foam (1), but swaps zinc chloride to nitrogen (2) and ammonium sulphate to trace (4).
Exam Preparation Tips
Focus on standard roles in microbial media: carbohydrates for carbon, salts for nitrogen/trace elements, and antifoams for industrial scalability. Practice similar matching questions from GATE BT papers to master biochemistry applications.
