Question

The ability of Lactococcus lactis subsp. diacetylactis to ferment citrate is encoded by

• A. Lac operon
• B. Plasmid
• C. Transposons
• D. 'Cit' plasmid

Hint:

Citrate fermentation: encoded by 'Cit' plasmid.
Found in Lactococcus lactis subsp. diacetylactis.
Produces diacetyl for flavour.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Certain metabolic abilities in bacteria are encoded by plasmids.
Citrate fermentation is a specific trait.
Step 2: Key Formula or Approach:
No specific formula.
Need to know the genetic basis of citrate fermentation.
Step 3: Detailed Explanation:
The ability of Lactococcus lactis subsp. diacetylactis to ferment citrate is encoded by the 'Cit' plasmid.
This plasmid carries the genes for citrate utilization.
The lac operon is for lactose metabolism.
Transposons are mobile genetic elements.
Thus, the 'Cit' plasmid is the correct answer.
Step 4: Final Answer:
The ability to ferment citrate is encoded by the 'Cit' plasmid.
Hence, the correct option is (D). \bigskip