Summary
Highlights
Our bodies are constantly carrying out chemical reactions, like breaking down food. To speed up these reactions at body temperature (37°C), the body uses enzymes. Enzymes act like biological scissors, breaking down large molecules into smaller ones. They can also join molecules together. Enzymes are biological catalysts that speed up chemical reactions without being used up.
Enzymes are specific; for example, proteins are broken down by enzymes into amino acids. Enzyme names often end in '-ase', like proteases (for proteins), carbohydrase (for carbohydrates), and lipase (for lipids).
The 'lock and key' model explains how enzymes work. A molecule called a substrate fits into a specific part of the enzyme called the active site, much like a key fits into a lock. The active site is complementary to the substrate, meaning each enzyme is specific to one particular substrate.
The 'induced fit' model suggests that the active site doesn't perfectly match the substrate initially. As the substrate binds, the active site's shape changes to fit around it, putting strain on molecular bonds and aiding in their breakage.
Enzymes are highly specific; each enzyme carries out only one specific reaction because its active site shape can only accommodate one particular substrate. This specificity allows the body to control reactions by regulating the production of particular enzymes.
Enzymes, being proteins, are sensitive to temperature. High temperatures can cause enzymes to 'denature,' meaning their shape changes, particularly the active site. When denatured, the active site no longer fits the substrate, and the reaction cannot proceed, leading to a decrease in the reaction rate.
A quiz challenges viewers on key facts about enzymes: their composition (proteins, not carbohydrates), their specificity (lipase cannot break down carbohydrates), and the conditions under which they denature (not all enzymes denature at 40°C, varying with different enzymes and environments).