Metabolism and Enzymes

Flashcards about Metabolism and Enzymes

Metabolism

The sum of all the chemical reactions in a cell.

Enzymes

Special proteins that perform metabolic chemical reactions.

Kinetic Energy

Energy of movement; includes light, sound, and physical movement.

Potential Energy

Energy of position; includes the energy stored in chemical bonds.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Second Law of Thermodynamics

Energy transformations are not 100% efficient; some energy is lost as heat.

Endergonic Reactions

Reactions that require an input of energy and store energy; tend to be anabolic.

Exergonic Reactions

Reactions that release energy into the environment; tend to be catabolic.

Energy Coupling

Pairs the energy released from exergonic reactions to drive endergonic reactions, often using ATP.

Activation Energy

The energy that must be overcome for a chemical reaction to begin; enzymes lower this barrier.

Substrate

A molecule upon which an enzyme acts.

Active Site

The specific region of an enzyme that binds the substrate and where catalysis occurs.

Inhibitor

A chemical that interferes with an enzyme’s activity.

Competitive Inhibitors

Inhibitors that block substrates from entering the active site.

Noncompetitive Inhibitors

Inhibitors that bind to the enzyme somewhere other than the active site, changing its shape.