Question

Enzymes are kinetically important for many of the complex reactions necessary for plant and animal life to exist. However, only a tiny amount of any particular enzyme is required for these complex reactions to occur. Explain.

Short answer

Enzymes are biological catalysts that increase the rate of chemical reactions by lowering activation energy. Their high specificity ensures they only work on specific reactions, and their active site binds substrates, forming an enzyme-substrate complex. This leads to a conformational change, called the induced fit, which weakens substrate bonds, lowering activation energy. Due to enzymes' high catalytic efficiency and their ability to rapidly bind substrates, lower activation energy, and release products, they can facilitate complex biochemical reactions in small amounts. This is essential for plants and animals to function efficiently while using minimal resources.

Step-by-step solution

Introduction to Enzymes

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. They play a vital role in various processes in living organisms, including cellular respiration, digestion, and DNA replication. One remarkable characteristic of enzymes is their catalytic efficiency, meaning they can speed up reactions by a factor of millions without getting consumed in the process.

Enzyme-Substrate Specificity

Enzymes are highly specific for their substrates, which are the molecules they interact with to facilitate a reaction. The enzyme's active site is a unique region that has a specific shape and chemical properties to bind its substrate. This specificity ensures that enzymes can work only on specific reactions, avoiding unwanted side-reactions or interference with other cellular processes.

Enzyme Mechanism of Action

The enzyme's active site is responsible for its catalytic activity and substrate binding. When the substrate binds to the active site, it forms an enzyme-substrate complex. This binding causes a slight change in the enzyme's conformation, known as the induced fit, which enables the enzyme to weaken specific chemical bonds within the substrate, thereby lowering the activation energy required for the reaction to proceed.

Enzyme Catalytic Efficiency

Enzymes can be extremely efficient catalysts due to their high turnover number, which describes the number of substrate molecules converted into product by a single enzyme molecule in a specific time. This high efficiency is achieved through rapid binding and release of the substrate and products, allowing each enzyme molecule to catalyze multiple reactions, turning over thousands of substrate molecules into product molecules per second.

Conclusion: Tiny Amount of Enzymes Required

Given their high catalytic efficiency and substrate specificity, enzymes can facilitate complex biochemical reactions rapidly and effectively, even when present in tiny amounts. This efficiency is due to their ability to bind substrates, lower the activation energy and release products quickly, enabling enzymes to participate in multiple reactions in a short period. This allows plants and animals to maintain the necessary biochemical processes with minimal consumption of their limited resources.