Which factor increases enzymatic speed?

Which factor increases enzymatic speed?

• A. Rising temperature
• B. substrate concentration
• C. pH
• D. Loss of electrons

Answer: (B)

Increasing substrate concentration raises the rate of an enzyme-catalyzed reaction because more substrate molecules are available to bind the active sites, forming enzyme–substrate complexes more often. This speeds up turnover until all enzyme molecules are busy—when enzymes are saturated—at which point adding more substrate cannot increase the rate any further. This relationship is described by Michaelis–Menten kinetics: at low substrate levels, the rate climbs as [S] rises, while at high substrate levels the rate approaches a maximum velocity (Vmax). Rising temperature can speed up reactions by giving molecules more kinetic energy, but only up to an optimum temperature; beyond that, the enzyme may denature and activity falls. pH affects the ionization of active site residues and substrates, altering binding and turnover; outside the optimum pH, activity drops. Loss of electrons isn’t a typical driver of enzymatic speed in this context, so it doesn’t increase the rate.

Increasing substrate concentration raises the rate of an enzyme-catalyzed reaction because more substrate molecules are available to bind the active sites, forming enzyme–substrate complexes more often. This speeds up turnover until all enzyme molecules are busy—when enzymes are saturated—at which point adding more substrate cannot increase the rate any further. This relationship is described by Michaelis–Menten kinetics: at low substrate levels, the rate climbs as [S] rises, while at high substrate levels the rate approaches a maximum velocity (Vmax).

Rising temperature can speed up reactions by giving molecules more kinetic energy, but only up to an optimum temperature; beyond that, the enzyme may denature and activity falls. pH affects the ionization of active site residues and substrates, altering binding and turnover; outside the optimum pH, activity drops. Loss of electrons isn’t a typical driver of enzymatic speed in this context, so it doesn’t increase the rate.