Question

Antibiotics can be used to kill the specific pathogenic bacterium, Mycobacterium tuberculosis, that causes tuberculosis. The appearance of antibiotic-resistant strains has made it more difficult to cure M. tuberculosis infections. These antibiotic-resistant bacteria survive and pass on the genes to their offspring, making the resistant phenotype more common in the population. DNA analysis indicates that the genes for antibiotic resistance are not normally present in bacterial chromosomal DNA. Which of the following statements best explains how the genes for antibiotic resistance can be transmitted between bacteria without the exchange of bacterial chromosomal DNA?
a. The antibiotic-resistant bacteria release a hormone that signals neighboring bacteria to become resistant.
b. The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria.
c. The antibiotic-resistant bacteria are the result of bacteria that specifically modify their own chromosomal DNA to neutralize the antibiotics
d. The antibiotic alters the bacterial genome of each bacterium, which results in an antibiotic-resistant population.

Answer 1

Answer:

b. The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria.

Explanation:

Transformation is a genetic process by which bacteria take up foreign genetic material from the surrounding environment. In consequence, this process does not involve direct cell-to-cell interaction. Transformation allows the occurrence of horizontal gene transfer (HGT) events among different bacteria capable of exchanging extrachromosomal DNA plasmids, thus increasing genetic diversity in bacteria. Many different types of bacteria can acquire foreign genes, including antibiotic resistance genes, by HGT events involving plasmids, transposable elements, bacteriophages, etc.