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A biotechnology… (Class 12 Biology SQP 2026-27, Q11)

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BiologyCBSE Class 12 · Sample paper, session 2026-27 · 1 mark · MCQ

CBSE Class 12 Biology sample paper 2026-27: question 11

From the official CBSE sample question paper for 2026-27, section A, question 11, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q11 · 1 mark · MCQCompetency-basedBiotechnology: Principles and Processes

A biotechnology company grew Streptomyces in a fermenter to produce an antibiotic. It was observed that Day 7 onwards, the actual yield drops sharply, even though nutrient level, temperature, and aeration remain unchanged. Also, Microscopy revealed new colonies of bacteria which were not present in the original culture. So the fermenter was stopped.
What measures should be taken to prevent the fall in yield in future fermentations?

  1. (A)Increasing temperature only at the end of fermentation to kill contaminants.
  2. (B)Adding antibiotics to the culture so unwanted microbes cannot grow.
  3. (C)Ensuring sterile handling, sterilised equipment, and aseptic transfer before and during fermentation.
  4. (D)Using a genetically modified strain designed to grow faster than contaminants.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

Open one hint at a time and try again before the next.

Hint 1

What did the microscopy reveal?

Hint 2

Prevention of contamination is better than trying to kill contaminants afterwards.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. The fall in yield was caused by contaminating bacteria, not by any change in growth conditions.

  2. Contamination is best prevented by aseptic technique: sterilised equipment and media, and sterile transfer before and during fermentation. Option (C).

    1 mark

Answer: (C)

Where the marks are

  • Identifies aseptic technique as the way to prevent contamination (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Biotechnology: Principles and Processes, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.