Molecule often produced by a microorganism to kill other microorganisms that might compete for the same food source? It usually works by dissipating essential electrochemical gradients in the competing organism.

Bacteriocin

Explanation:

Bacteriocin is a ribosomally synthesized compounds produced by bacteria that are active against closely related bacteria

Bacteriocin consists of 20-60 amino acidsMost bacteriocin target cell membranes while some inhibit the biosynthesis of biopolymersBacteriocin dissipate the proton motive force by disrupting the pH gradient of disruptive cells,they do so by forming pores in the target cellsPore formation ultimately results in the leakage of inorganic phosphates and an ionic imbalance;The initial disturbance causes dissipation of the proton motive force which encompasses a complete or partial dissipation of either or both the electrochemical gradient and the transmembrane potential

The answer is a if u read the definition it makes sense

Active site is where they touch.