I believe the answer to your question would be:
<span>phosphate heads of phospholipid</span>
I know this isn't answering your question but i think you will find it useful to visit the link pasted below. i just visited it and it explains pretty much everything about this.
Answer & Explanation:
Feedback is a form of regulation where the main product of one reaction, can also inhibit it. It can work in several ways, mainly there's a receptor that, somehow, measures the presence of a determined molecule, in this case, ATP. These receptors can also be involved in the metabolic process and when there's an excess of ATP, the enzymes are inhibited, maybe with an allosteric type of inhibition.
