Ace A Level Biology 2025 – Dive Deep and Conquer Science!

Enzymes are primarily categorized as globular proteins due to their specific three-dimensional structures that are critical for their function. Globular proteins are characterized by their compact, spherical shape, which allows them to be soluble in water. This solubility is important for enzymes, as they need to interact with various substrates in aqueous environments within biological systems.

The structure of globular proteins is essential for forming active sites, where substrate molecules bind and undergo chemical reactions. This functionality is a defining characteristic of enzymes, which act as biological catalysts, speeding up metabolic reactions without being consumed in the process. The precise arrangement of amino acids in the active site allows for specificity, enabling enzymes to catalyze particular reactions efficiently.

In contrast, fibrous proteins tend to have elongated structures and are often involved in the development of tissues (such as collagen), serving structural roles rather than catalytic functions. Structural proteins and transport proteins also play important roles in organisms but are not primarily involved in catalysis like enzymes are.