Final answer:
Enzymes are biological catalysts that speed up biochemical reactions by lowering activation energy. They work by providing an optimal chemical environment at their active site. In lab experiments, initial resistance to a reaction can be overcome by increasing temperature, changing reactant concentration, or adding a catalyst.
Step-by-step explanation:
Enzymes: Definition and Function
Enzymes are biological catalysts that speed up biochemical reactions in organisms. They are usually proteins consisting of one or more polypeptide chains. Enzymes work by lowering the activation energy required for a chemical reaction to occur, thereby increasing the reaction rate. They achieve this by providing an optimal chemical environment at their active site, where the substrate molecules bind and undergo the reaction.
How Enzymes Speed Up Reactions
Enzymes speed up reactions by:
Lowering activation energy: Enzymes provide an alternative reaction pathway that requires less energy for the reaction to proceed. This lowers the activation energy barrier and allows the reaction to occur more readily.
Bringing substrates together: Enzymes bring together the reactant molecules (substrates) in the correct orientation for a reaction to take place.
Inducing favorable environments: Enzymes create optimal conditions, such as the presence of specific ions or appropriate pH, for the reaction to occur efficiently.
Participating in the reaction: Some enzymes directly participate in the chemical reaction by forming temporary bonds with the substrates, facilitating the necessary chemical transformations.
Overcoming Initial Resistance in Lab Experiments
In lab experiments, the initial resistance to a reaction can be overcome by:
Increasing temperature: Raising the temperature provides more energy to the reactant molecules, increasing the likelihood of successful collisions and overcoming the activation energy barrier.
Changing reactant concentration: By increasing the concentration of reactant molecules, the chance of successful collisions between the reactants also increases, leading to a higher reaction rate.
Adding a catalyst: Catalysts, including enzymes, can be added to the reaction mixture. They lower the activation energy and speed up the reaction without being consumed in the process.