Enzyme kinetics graph axes identification

Steps:

• Enzyme-catalyzed reaction graphs typically plot rate of reaction (y-axis) against a variable factor (x-axis) like substrate concentration, pH, or temperature.
• Rate of reaction measures product formation or substrate depletion over time, always on y-axis in such plots.
• Common trends: hyperbolic for substrate concentration, bell-shaped for pH, sigmoidal then declining for temperature.
• Match option to standard pH effect on enzymes, which shows optimal pH with declining rates on either side.

Why C is correct:

• Enzyme activity follows a bell curve versus pH due to optimal ionization of active site residues, as per enzyme-substrate complex stability principles.

Why the others are wrong:

• A: Reverses axes; rate depends on substrate concentration, not vice versa.
• B: Enzyme concentration linearly increases rate, not a temperature plot; axes mismatched.
• D: Reverses axes and confuses pH with substrate; pH is environmental, not substrate quantity.

Final answer: C