Sulfa antibiotics damage bacteria by affecting a certain bacterial enzyme. The sulfa antibiotic looks similar to a substrate nor
mally required by the bacterial cells to live. The sulfa antibiotic occupies the active site of the required enzyme and blocks entry of its normal substrate. This prevents the bacteria from making nucleotides that are required for their reproduction and survival. Based on this information, the action of sulfa antibiotics is an example of
because the substrate and the antibiotic do not compete for active sites but rather the antibiotic inhibits the site blocking the normal substrate completely
