Step I Nbme 3. Bacterial genetics

[RedSoxSuck]

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Bacterial strain X is resistant to Ampicillin and sensitive to Gentamycin. Bacterial strain Y is resistane to gentamycin and sensitive to Ampicillin. Bacterial strain X and Y are grown in mixed culture in medium without antibiotics, then the culture is plated on medium containing both ampicillin and gentamycin. Bacterial colonies grow on the plate. In a second experiment DNase is added to a mixed culture medium. When this mixed culture is plated on medium containning both antibiotics ,no colonies grow. Assuming that bacterial cells are impermeable to DNase, which of the following processes best explain these observations?

A- Conjugation
B- Mutation
C- Transduction
D- Transformation
E- Transposition

Answer key says A is the answer. I chose D but i am sure.

Thanks

 

[thehundredthone]

If the DNase is able to prevent uptake of, well, DNA, then it's transformation. Transduction and conjugation are both DNase resistant.

Take the NBME offline "Answer keys" with a pinch of salt as and when needed.

Here's some Phloston and Myxedema wisdom for you:
http://forums.studentdoctor.net/archive/index.php/t-941636.html

 

[RedSoxSuck]

If the DNase is able to prevent uptake of, well, DNA, then it's transformation. Transduction and conjugation are both DNase resistant.

Take the NBME offline "Answer keys" with a pinch of salt as and when needed.

Here's some Phloston and Myxedema wisdom for you:
http://forums.studentdoctor.net/archive/index.php/t-941636.html

So the answer is transformation and i was CORRECT? If yes then +1 for me.