Question

The problem of pathogenic bacteria becoming resistant to a large number of antibiotics is a serious public health concern. A bacterial strain in a paticnt being treated with one antibiotic may suddenly become resistant not only to that antibiotic but to others as well even though it has not been exposed to the other antibiotics. This occurs when the bacteria acquire a plasmid from another strain that contains several different transposons. In the operation of transposons, A. ryplcally the transposon moves from its original site and relocares to a different site. B. a duplicated transposon must be inserted into the same DNA molecule as the original. C. all transposons are approximately the same size. D. the insertion sites must be in a consensus sequence. E. the transposase may recognize the repetitive ends of the transposon and participate in the cleavage of the recipient site.

Short answer

A) Typically, the transposon moves from its original site and relocates to a different site. B) A duplicated transposon must be inserted into the same DNA molecule as the original. C) All transposons are approximately the same size. D) The insertion sites must be in a consensus sequence. E) The transposase may recognize the repetitive ends of the transposon and participate in the cleavage of the recipient site. Answer: A and E

Step-by-step solution

Statement A

Typically, the transposon moves from its original site and relocates to a different site. This statement is correct. Transposons, also known as "jumping genes," can move from one location to another within a DNA molecule. This movement of transposons is what leads to the spread of antibiotic resistance in bacteria.

Statement B

A duplicated transposon must be inserted into the same DNA molecule as the original. This statement is incorrect. Duplicated transposons can be inserted into the same DNA molecule, but they can also be inserted into different DNA molecules.

Statement C

All transposons are approximately the same size. This statement is incorrect. Transposons vary in size and can range from a few hundred to several thousand base pairs in length.

Statement D

The insertion sites must be in a consensus sequence. This statement is incorrect. Although some transposons preferentially target specific sequences, there is no strict requirement for a consensus sequence for insertion.

Statement E

The transposase may recognize the repetitive ends of the transposon and participate in the cleavage of the recipient site. This statement is correct. Transposase is an enzyme that is responsible for cutting the DNA at the target site and then inserting the transposon at the cut site. Transposase recognizes the repetitive ends of the transposon, which are essential for its movement. In conclusion, the correct statements about the operation of transposons are A and E.