Transcription and translation are the two proocesess involved in gene expression. These two processes are important because the end result is a PROTEIN responsible for the phenotypic characteristics of that organism. Transcription involves synthesis of mRNA from DNA while translation involves synthesis of protein from mRNA.
In this question, an antibiotics called Puromycin forces the ribosome to detach from the mRNA chain before reaching the stop codon. This means that the antibiotics "Puromycin" abruptly truncates the translation process. Hence, proteins will not be produced. This means that the organism (bacteria) will not be functionally active because of lack of necessary PROTEINS.
