Enzyme: A biological catalyst โ a protein that speeds up a chemical reaction without being used up in the process.
Active site: The specific region on an enzyme molecule where the substrate binds; its shape is complementary to that of the substrate.
Substrate: The specific molecule that an enzyme acts upon, fitting into the active site.
Denaturation: The permanent change in shape of an enzyme's active site caused by high temperature or extreme pH, making the enzyme non-functional.
Optimum temperature: The temperature at which an enzyme works at its fastest rate; for most human enzymes this is approximately 37ยฐC.
Optimum pH: The pH at which a particular enzyme works at its fastest rate; this varies between enzymes (e.g. pepsin pH 1.5, amylase pH 7, trypsin pH 8.5).
This definitions covers Key Definitions within Enzymes in Digestion for GCSE Biology. Enzyme structure and function, digestive enzymes, factors affecting enzyme activity, lock and key model, and practical investigations It is section 14 of 19 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for Enzymes in Digestion
What are enzymes?
Explain the effect of increasing temperature on enzyme activity.
Quick recall flashcards
What does lipase do?
Breaks down lipids (fats) into fatty acids and glycerol. Produced by pancreas, works in small intestine.
What is an enzyme?
A biological catalyst that speeds up chemical reactions by lowering activation energy. Enzymes are proteins with specific 3D shapes.