Question

Bacterial conjugation

• A. occurs through the uptake of free DNA from environment
• B. requires direct contact between two bacterial cells through pilus
• C. involves the transfer of genetic material from virus to bacteria
• D. is a form of asexual reproduction

Hint:

Transformation = uptake of free DNA, Transduction = virus-mediated transfer, and Conjugation = direct cell-to-cell DNA transfer through pilus.

Answer 1

The Correct Option is B

Step 1: Understand bacterial conjugation.
Bacterial conjugation is a mechanism of horizontal gene transfer in which genetic material is transferred from one bacterial cell to another.

Step 2: Identify the requirement for conjugation.
Conjugation requires physical contact between donor and recipient bacterial cells. This contact is established by a structure called the sex pilus or conjugation pilus.

Step 3: Analyze option (A).
Uptake of free DNA directly from the environment is called transformation, not conjugation. Therefore, option (A) is incorrect.

Step 4: Analyze option (B).
During conjugation, the donor bacterium transfers plasmid DNA or chromosomal DNA to the recipient through direct contact via pilus. Hence, option (B) is correct.

Step 5: Analyze option (C).
Transfer of genetic material from viruses to bacteria is called transduction, which is mediated by bacteriophages. Thus, option (C) is incorrect.

Step 6: Analyze option (D).
Conjugation is not reproduction because it does not increase bacterial number. It only transfers genetic information between cells. Therefore, option (D) is incorrect.

Step 7: Final conclusion.
Hence, bacterial conjugation requires direct contact between two bacterial cells through pilus.
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Therefore, the correct answer is option (B).