An enzyme is a:


a. biological catalyst that increases the concentration of the products.
b. biological catalyst that increases the concentration of the reactants.
c. chemical that is used in a reaction, after which it can no longer be used by the cell.
d. biological catalyst that works by bringing its substrates closer to their transition states.

Verified step by step guidance

1. Understand that enzymes are proteins that act as biological catalysts.
2. Recognize that catalysts speed up chemical reactions without being consumed in the process.
3. Identify that enzymes work by lowering the activation energy needed for a reaction to proceed.
4. Note that enzymes achieve this by stabilizing the transition state and bringing substrates closer to it.
5. Conclude that the correct description of an enzyme is a biological catalyst that works by bringing its substrates closer to their transition states.

Key Concepts

Enzymes as Biological Catalysts

Enzymes are proteins that act as biological catalysts, meaning they accelerate chemical reactions without being consumed in the process. They lower the activation energy required for reactions, allowing them to occur more quickly and efficiently. This catalytic function is crucial for various biological processes, including metabolism and DNA replication.

Substrate and Active Site Interaction

The active site of an enzyme is a specific region where substrates bind. This interaction is highly specific, often described by the 'lock and key' model, where the enzyme's active site (the 'lock') is shaped to fit a particular substrate (the 'key'). This proximity facilitates the transition state, leading to the formation of products more efficiently.

Transition State Theory

Transition state theory posits that during a chemical reaction, reactants must reach a high-energy state known as the transition state before converting into products. Enzymes stabilize this transition state, effectively lowering the energy barrier and increasing the likelihood of the reaction occurring. This concept is fundamental to understanding how enzymes enhance reaction rates.