Enzymes and Catalysts

Vocabulary flashcards based on lecture notes covering the properties of catalysts and the functions of specific enzyme classes.

Catalyst

Specially speeds up a reaction by lowering the activation energy; it is not consumed or permanently changed in the reaction.

Activation energy barrier

The energy requirement that a catalyst lowers to allow more molecules to reach the transition state, resulting in a faster reaction rate.

Free energy ($\Delta G$)

The overall energy change of a reaction which is NOT changed by a catalyst.

Equilibrium position

The final state of a reaction that a catalyst does not change; instead, the catalyst only allows the reaction to reach it faster.

Enzymes

Proteins that make up the majority of biological catalysts.

Ribozyme

An RNA molecule that acts as an enzyme or catalyst.

Kinase

An enzyme that adds a phosphate to a substrate using $ATP$ as the phosphate donor.

Phosphatase

An enzyme that removes a phosphate group from its substrate.

Phosphorylase

An enzyme that adds a phosphate to a substrate using inorganic phosphate ($P_i$) rather than $ATP$.

ATPase

An enzyme that hydrolyzes $ATP$ to $ADP + P_i$, breaking the $ATP$ to release energy.

Isomerase

An enzyme that rearranges atoms within a molecule to form an isomer, which has the same formula but a new structure.

Dehydrogenase

A redox enzyme that removes $H$ / electron from a molecule and transfers them to carriers like $NAD^+$ or $FAD$.