OCR A-Level Biology 2.1.4 Enzymes (copy)

not finished

Enzyme

Biological catalyst, specific to one particular substrate/reaction. Globular protein

Why are enzymes important?

Without enzymes, biological reactions would take much longer or might not happen, and biological processes necessary to life might

Anabolic reactions

Chemical reactions required for growth, which build up molecules and other structures

Catabolic reactions

Chemical reactions which break down molecules and structures to release energy. Catalysed by enzymes

Metabolism

the sum of all the different reactions and reaction pathways happening in a cell or organism

Vmax

the maximum initial velocity or rate of an enzyme-catalysed reaction, which happens when enzymes have formed an enzyme-substrate complex at any given moment.

activation energy

The initial energy required for a reaction to take place.

Lock and key hypothesis

The idea that every enzyme has an active site complementary to only one substrate, and they fit together like a lock and key. An enzyme-substrate complex is formed and the substrate or substrates react, forming an enzyme-product complex which then releases the products. The substrate is held in such a way that the right atom groups are close enough to react.

Intracellular enzymes

Enzymes that act within cells