How do enzymes work on a molecular level?

How do enzymes work on a molecular level?

• A. They shift the equilibrium of the reaction
• B. They bind to reactants and hold them so that bond-breaking and bond-forming occur more readily
• C. They are consumed during the reaction
• D. They increase temperature to speed reactions

Answer: (B)

Enzymes speed up reactions by binding to the reacting molecules and holding them in the right orientation so that bonds can break and form more easily. This creates an enzyme–substrate complex, and the active site provides a environment that stabilizes the transition state—the high-energy arrangement of atoms involved in the reaction. By stabilizing that transition state, the energy barrier (activation energy) is lowered, so the reaction proceeds faster. Importantly, the enzyme isn’t consumed in the process and can catalyze many cycles. They don’t change the overall balance of reactants and products. The same amount of energy difference governs the equilibrium, just more molecules get over the barrier per unit time. They also don’t raise the reaction’s temperature; they work through specific chemical interactions at physiological temperatures. The precision of the active site explains why enzymes are highly specific for particular substrates and reactions.

Enzymes speed up reactions by binding to the reacting molecules and holding them in the right orientation so that bonds can break and form more easily. This creates an enzyme–substrate complex, and the active site provides a environment that stabilizes the transition state—the high-energy arrangement of atoms involved in the reaction. By stabilizing that transition state, the energy barrier (activation energy) is lowered, so the reaction proceeds faster. Importantly, the enzyme isn’t consumed in the process and can catalyze many cycles.

They don’t change the overall balance of reactants and products. The same amount of energy difference governs the equilibrium, just more molecules get over the barrier per unit time. They also don’t raise the reaction’s temperature; they work through specific chemical interactions at physiological temperatures. The precision of the active site explains why enzymes are highly specific for particular substrates and reactions.