Proteins and Enzymes: Structure and Function

Proteins are complex molecules formed from amino acid chains, with their sequence determined by DNA. They play crucial roles in cellular functions, including:

1. Structural support
2. Enzymatic catalysis
3. Hormonal signaling
4. Immune defense (antibodies)
5. Cellular reception

Enzymes, a specific type of protein, act as biological catalysts. They speed up chemical reactions without being consumed in the process. The specificity of enzymes is due to their unique active site, which complements the shape of their substrate.

Definition: The active site is the region on an enzyme where the substrate binds and the reaction occurs.

The enzyme-substrate complex forms when a substrate attaches to the enzyme's active site. This complex is crucial for the catalytic process.

Vocabulary: Enzyme-substrate complex - The temporary structure formed when an enzyme binds to its specific substrate.

Enzymes catalyze two main types of reactions:

1. Synthesis reactions: Building larger molecules from smaller ones (e.g., glucose to starch)
2. Degradation reactions: Breaking down larger molecules into smaller ones (e.g., proteins to amino acids)

Example: In starch synthesis, an enzyme combines glucose molecules to form larger starch molecules.