What component is present in every part of a loop, such as one that involves proteins producing energetic molecules from sugar?

Are you the same person as here?
Asking twice won't get your question asked any more quick :)

This is apparently a common test question. Also see the links at the bottom of this page.

What component is present in every part of a loop, such as one that involves proteins producing energetic molecules from sugar?

Hey there... There are links provided by RickJ. Try them before asking the same question as the... well... the question of the topic.