Enzymes and Bioenergetics

Vocabulary flashcards covering cellular energy, ATP, enzyme activity, inhibition, and metabolic pathway regulation based on the lecture notes.

$$\Delta G = 0$$

A condition in which no work can be done and the system is at equilibrium (no energy), which will not support life.

Coupled Reactions

The pairing of endergonic reactions with exergonic reactions in cells so that endergonic reactions will occur.

ATP

An energy transfer molecule in cells that stores energy in its three phosphate bonds for later use.

Enzymes

Catalysts (usually proteins) that speed up and control reactions without altering the reaction or causing an impossible reaction to occur.

Energy of Activation ($E_A$)

The amount of energy that the reactants must absorb to break enough bonds for the reaction to occur.

Cofactors

Small non-protein molecules required for an enzyme to work properly, which may be inorganic (e.g., iron) or organic (e.g., vitamins).

Co-enzymes

Organic cofactors, such as certain vitamins, required for an enzyme to function properly.

Reversible Enzyme Inhibitors

Enzyme inhibitors that bind to an enzyme through weak bonds.

Irreversible Enzyme Inhibitors

Enzyme inhibitors that bind to an enzyme through covalent bonds.

Competitive Inhibitors

Molecules that resemble a substrate and compete with it for binding at the active site on the enzyme.

Non-competitive Inhibitors

Inhibitors that do not bind to the active site, but to another part of the enzyme, changing its shape so it cannot bind to the actual substrate.

Allosteric Site

A specific receptor site on some part of an enzyme other than the active site.

Allosteric Enzymes

Enzymes that possess two shapes or conformations: an active form and an inactive form.

Cooperativity

A mechanism of metabolic regulation where substrate molecules themselves increase the activity of an enzyme.

Feedback Inhibition

A regulatory mechanism in which the formation of a product inhibits an enzyme in its pathway, preventing the cell from wasting resources to build a product that is already sufficient.