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GATE 2025 BT – Question 23

Fundamentals of Biological Engineering · Downstream Processing: Filtration, centrifugation, cell disruption, chromatography, extraction, adsorption and drying · 1 mark · Multiple select

Which of the following separation processes is/are based on molecular size?

  1. Size-exclusion chromatography
  2. Ion exchange chromatography
  3. Membrane ultrafiltration
  4. Ultracentrifugation

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Show answer and explanation

Correct answer: (A) Size-exclusion chromatography; (C) Membrane ultrafiltration; (D) Ultracentrifugation

Explanation

Size-exclusion chromatography and ultrafiltration separate molecules by size. Ultracentrifugation separates by the sedimentation rate, which grows with the size and mass of a particle. Ion exchange is based on charge.

Official GATE 2025 answer key: https://gate2026.iitg.ac.in/doc/download/2025_Key/BT_Keys.pdf