Enzyme Fundamentals
📌 Enzymes are biological catalysts made in living cells that increase the rate of chemical reactions without being consumed themselves.
🧬 A substrate is the substance an enzyme acts upon, resulting in products after the reaction completes.
🧩 Enzymes possess a specific shape called the active site that must be complementary to the substrate's shape, often referred to as the lock and key mechanism.
🔄 Enzymes are specific; an enzyme acting on one substrate will not work with a differently shaped substrate.

Factors Affecting Enzyme Activity: Temperature
🌡️ Increasing temperature initially increases the reaction rate because molecules gain more kinetic energy, leading to more successful collisions.
🎯 Every enzyme has an optimum temperature where it works best; for many human enzymes, this is approximately 37°C.
🔥 Temperatures that are too high cause enzymes to denature, breaking bonds and permanently changing the active site shape, rendering the enzyme non-functional.
📉 Low temperatures slow reactions due to reduced kinetic energy but do not denature enzymes.

Factors Affecting Enzyme Activity: pH
🧪 Enzymes have an optimum pH at which their activity is highest; deviation from this optimum causes denaturation.
🍏 Pepsin, found in the stomach, functions best at an acidic optimum pH of approximately 2.
🍞 Amylase, found in saliva, has an optimum pH of 7 (neutral).
📉 Moving too far from the optimum pH on either side causes the active site shape to change, preventing substrate binding.

Key Points & Insights
➡️ Enzymes are reusable catalysts essential for speeding up metabolic reactions necessary for life, like digestion.
➡️ Successful enzyme action relies on the complementary fit between the active site and the substrate, illustrating enzyme specificity.
➡️ Temperature affects activity by influencing molecular collision energy; denaturation occurs above the optimum temperature (e.g., human enzymes above 50°C).
➡️ Optimal pH is crucial; for example, pepsin requires pH 2, while amylase requires pH 7, demonstrating that different enzymes function in different environments.

📸 Video summarized with SummaryTube.com on Nov 30, 2025, 13:53 UTC