Enzymes and Biocatalysis

Flashcards covering the properties, functions, and naming conventions of enzymes and catalysts as described in the lecture notes.

What is defined as the minimum amount of energy required to start a chemical reaction?

Activation energy

What is a catalyst?

A substance that accelerates a reaction without being changed or used up by lowering the activation energy.

Why do chemical reactions in living organisms proceed in many steps rather than occurring all at once?

To release small amounts of energy at each step so the organism can utilize it and to prevent the release of high heat that would harm the organism.

What are enzymes?

Catalysts that are found in living organisms.

What is a substrate?

The specific molecule upon which an enzyme acts.

What is the active site?

The specific region on an enzyme molecule where the reaction between the enzyme and its substrate occurs.

What suffix is commonly added to the name of a substance or reaction to name its corresponding enzyme?

-ase (e.g., sucrase, protease, lipase, and maltase)

Which two enzymes are cited as being named without the standard "-ase" suffix?

pepsin and trypsin

How are pepsin and trypsin activated in the body according to the text?

pepsin is the activated form of pepsinogen with $HCl$ in the stomach, and trypsin is the activated form of trypsinogen in the duodenum.

Which enzymes are mentioned as being composed only of proteins?

pepsin, urease, and amylase

What is an apoenzyme?

The protein part of an enzyme.

What is a cofactor?

The non-protein part of an enzyme, which is either a vitamin or a mineral.

What is a coenzyme?

The non-protein part of an enzyme specifically made up of vitamins.

What is an enzyme-substrate complex?

An unstable association formed between an enzyme and its substrate that is easily broken down into new substances.

What is the lock and key hypothesis?

A model explaining that an enzyme functions because its active site fits a specific substrate like a lock fits a specific key.