Final answer:
Enzymes accelerate biochemical reactions by lowering the activation energy, which is the initial energy required to start a reaction. They achieve this by binding to reactants at the active site, correctly orienting them and sometimes even participating in the reaction, without being consumed.
Step-by-step explanation:
Enzymes are biological catalysts that speed up biochemical reactions by lowering the activation energy required for the reaction to occur. Activation energy is the amount of energy necessary to initiate a chemical reaction, involving the formation or breaking of chemical bonds.
Enzymes reduce activation energy by creating a favorable environment where reactant molecules, called substrates, can come together. This occurs within a specific region on the enzyme known as the active site. The correct geometric orientation provided by the enzyme aligns the substrate molecules, facilitating the proper conditions for the reaction to take place at a lower energy cost. The enzyme-substrate complex aids in contorting substrate molecules to make bonds easier to break, thus reducing the energy required to reach the transition state. Additionally, enzymes may participate directly in the reaction, offering specific amino acid residues that can form temporary covalent bonds with substrate molecules, effectively providing an alternate route for the reaction with lower activation energy. After the reaction, enzymes release the product and return to their original state, remaining unaffected by the process. By decreasing the activation energy, enzymes increase the rate of cellular reactions critical to life processes without being consumed or altered by the reaction itself.