An adaptive walk of beta-lactamase in response to selective pressure exerted by cefotaxime likely involved:
A)the random generation of five changes that provide microbial resistance to the antibiotic.
B)sequential changes in single amino acids that each provided an incremental level of resistance to the antibiotic.
C)increased genetic change induced by selective pressure exerted by the antibiotic.
D)one clear beneficial change and several non-impactful changes in the gene.
E)major shifts in the metabolic pathways in the microbe under selection.

Question

Quizplus · Accepted Answer

An adaptive walk involves sequential changes in a gene, with each change providing an incremental level of adaptation to the selective pressure. Therefore, option B is the best choice since it suggests that the beta-lactamase changes via small incremental changes in single amino acids to adapt to selective pressure exerted by cefotaxime. Option A suggests changes generated randomly, and option C is vague as it does not explain the specific mechanisms of the genetic changes induced by the antibiotic. Option D suggests a clear beneficial effect but with several non-impactful changes, which is not representative of an adaptive walk. Option E suggests a shift in the metabolic pathway, which is not relevant to the adaptation of the beta-lactamase gene to antibiotic pressure.

An Adaptive Walk of Beta-Lactamase in Response to Selective Pressure