Enzymes - CIE Biology IGCSE

Overview

Enzymes are proteins functioning as biological catalysts.
- Catalysts speed up chemical reactions without being consumed.
- Enzymes remain unchanged post-reaction and are reusable.
Essential for speeding up metabolic reactions that would otherwise proceed too slowly.

Active Site: Specific sequence of amino acids forming a shape complementary to the substrate.
- Enzyme-Substrate Complex: Formed when substrate enters the active site.
- Substrate is broken down and product is released, allowing enzyme to bind to another substrate.
Specificity: Each enzyme is specific to a particular substrate type.
- Example:
  - Proteases break down proteins into amino acids.
  - Carbohydrases are required to break down carbohydrates.

pH:
- Enzymes have an optimal pH.
- Deviations from optimal pH alter active site shape, hindering substrate binding.
- Leads to enzyme denaturation and decreased reaction rate.
Temperature:
- Reaction rate increases with temperature up to the enzyme's optimal point due to increased kinetic energy and successful collisions.
- High temperatures beyond the optimum lead to enzyme denaturation and altered active site shape, decreasing reaction rate.