"performs a function" is correct and usable in written English.
You can use it to describe when an object or person performs a specific task or action. For example, "The computer performs a function of controlling the lights in the building."
Intuitively, if a functional module performs a function that requires a sequence of steps (like in the case of a signaling pathway) then we would like functional groups to be snapshots of protein associations at these steps.
But the fact that a design feature performs a function does not make it essential to the performance of that function; it is instead the absence of alternative constructions performing the same function that renders the feature functional.
Thus, the true test of functionality is not whether the feature in question performs a function, but whether the feature "is dictated by the functions to be performed," Warner Bros. Inc. v. Gay Toys, Inc., 724 F.2d 331, 331 (2d Cir.1983) (quoted in LeSportsac, Inc. v. K mart Corp., 754 F.2d at 76), as evidenced by available alternative constructions.
WaterMinder, by contrast, performs a function more traditionally fulfilled by the human brain — specifically, the hypothalamus, which regulates thirst.
WaterMinder, by contrast, performs a function more traditionally fulfilled by the human brain specifically, the hypothalamus, which regulates thirst.
Exaptation a feature that performs a function but that was not produced by natural selection for its current use.
To perform a function, the user taps twice.
Parking garages perform a function, but truffles delight the palate, a much higher calling.
"I think that our organizations in some ways perform a function similar to that of an old-fashioned social club".
Zoetropes, kaleidoscopes, stereopticons: these optical devices performed a function similar to that of contemporary painting and fiction.
Of course, the navy often took them on ships, but there they performed a function, mousing for the officers.
