A. P-ii, Q-i, R-iii, S-i

B. P-i, Q-iv, R-iii, S-ii

C. P-iv, Q-iii, R-ii, S-i

D. P-iii, Q-i, R-ii, S-iv

The correct answer is B. P-i, Q-iii, R-iv, S-ii.
This matching reflects standard elution conditions: DEAE-Sephadex (anion exchange) uses increasing NaCl, Chromatofocusing uses pH gradient, Phenyl Sepharose (HIC) uses decreasing (NH4)2SO4, and G-150 Sephadex uses isocratic elution.[ from prior context]

Option Explanations

A. P-ii, Q-i, R-iii, S-i incorrectly assigns isocratic to DEAE (needs salt gradient) and NaCl to Chromatofocusing (pH-based).

B. P-i, Q-iii, R-iv, S-ii correctly matches: DEAE-Sephadex (i: NaCl gradient), Chromatofocusing (iii: pH gradient), Phenyl Sepharose (iv: ammonium sulfate decrease), G-150 (ii: isocratic).

C. P-iv, Q-iii, R-ii, S-i mismatches DEAE with salt precipitation and G-150 with NaCl gradient.

D. P-iii, Q-i, R-ii, S-iv wrongly applies pH to anion exchange and HIC to size exclusion.

Chromatography Technique Matching

Chromatographic technique elution conditions DEAE-Sephadex Chromatofocusing represent core GATE Life Sciences concepts. Each method’s elution matches its separation principle: charge, pI, hydrophobicity, or size.

Technique-Elution Pairings

• DEAE-Sephadex (A): Anion exchanger; proteins bind at low salt, elute with increasing NaCl gradient (0.05-1 M).(i)

• Chromatofocusing (B): Polybuffer exchanger creates internal pH gradient; proteins elute at their pI.(iii)

• Phenyl Sepharose (C): Hydrophobic interaction; bind high (NH4)2SO4 (1.5 M), elute decreasing gradient.(iv)

• G-150 Sephadex (D): Size exclusion; isocratic buffer flow, no gradient needed.(ii)

Matching Table

GATE Exam Strategy

Option B is standard: exchange (salt), focusing (pH), HIC (salt decrease), SEC (constant). PYQs test principle-elution linkage over memorization.