Question

Free DNA fragments from the surrounding medium are taken up by competent bacterial cells during __________.

• A. transformation
• B. conjugation
• C. sex-duction
• D. transduction

Hint:

This process needs no cell contact or virus, just direct uptake of DNA from outside the cell.

Answer 1

The Correct Option is A

Step 1: Transformation is the process by which a bacterial cell takes up naked, free DNA fragments directly from its surrounding environment, without any cell-to-cell contact or a viral vector.

Step 2: Only certain bacteria in a physiological state called competence can efficiently take up this external DNA and, in some cases, integrate it into their own genome by recombination.

Step 3: Conjugation requires direct cell-to-cell contact through a pilus, transduction requires a bacteriophage to carry DNA between cells, and sex-duction (F-duction) is a special case of conjugation involving an F' plasmid carrying chromosomal genes, none of which involve simply absorbing free DNA from the medium.

Step 4: So the correct answer is transformation.