ATP, Energy Coupling, and Enzyme Function

Vocabulary flashcards covering ATP structure, energy coupling, enzyme properties, activation energy, and the factors affecting enzyme activity based on the lecture transcript.

Adenosine triphosphate (ATP)

The molecule that powers cellular work, storing potential energy in its phosphate bonds that is released upon breakdown.

Hydrolysis

A chemical breakdown reaction that requires the breakdown of a water molecule.

Exergonic reaction

A chemical reaction where energy is released, characterized by reactants having more energy than the products.

Endergonic reaction

A chemical reaction that requires an input of energy to proceed, characterized by reactants having lower energy than the products.

Energy coupling

The process where the energy released from an exergonic reaction is transferred to an enzyme to drive an endergonic reaction.

Rigor mortis

The stiffening of muscles that occurs after death due to the absence of ATP required to unbind myosin heads from actin filaments.

Catalyst

A chemical agent that speeds up a chemical reaction without being changed by the reaction itself.

Catalytic protein

A protein, also known as an enzyme, that speeds up a chemical reaction without being changed by that reaction.

Sucrase

The enzyme that catalyzes the breakdown of sucrose into glucose and fructose.

Activation energy

The initial input or bump of energy required to get a chemical reaction rolling, which enzymes lower.

Substrate

The specific molecule that an enzyme recognizes, interacts with, and binds to in its active site.

Active site

The specific region or binding site on an enzyme where a substrate binds.

Microenvironment

The local environment where an enzyme and substrate interact, which the enzyme can alter to help facilitate a chemical reaction.

Optimal temperature

The specific temperature at which an enzyme operates most effectively, which is $37\,^\circ\text{C}$ ($98.6\,^\circ\text{F}$) for most human enzymes.

Denaturation

The process where a protein unfolds and loses its functional shape due to excessive heat.

Pepsin

A protein-digesting enzyme that functions effectively in the highly acidic environment of the stomach.

Trypsin

A protein-digesting enzyme in the small intestine that functions most optimally around a pH of $8$.