Lecture Notes on Energy and Enzymes

Flashcards covering key concepts from a lecture on energy, thermodynamics, chemical reactions, enzymes, and metabolic pathways.

Energy

The ability to perform work— a transfer of energy that causes an overall change.

Potential Energy

Stored energy that is available to do work.

Kinetic Energy

Energy in motion.

Thermodynamics

The study of energy transfers between different bodies of matter.

System

The specific portion of matter being studied.

Surroundings

Everything else outside the system.

Biological Systems

Transfer both energy and mass with the surroundings.

First Law of Thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

Entropy

A measure of disorder/randomness in a system.

Second Law of Thermodynamics

100% efficient energy conversion is impossible, as heat energy is lost.

Heat

Form of kinetic energy transferred between two objects with different temperatures.

Chemical Reactions

The making or breaking of chemical bonds, leading to changes in matter.

Reactants

The starting material in a chemical reaction.

Products

The ending material in a chemical reaction.

Endergonic Reactions

Require an input of energy.

Exergonic Reactions

Release energy into the environment.

Adenosine Triphosphate (ATP)

A high-energy molecule used to power cellular activities.

ATP Hydrolysis

The process of breaking bonds between phosphate groups, generating chemical energy and ADP.

Energy Coupling

When energy released by an exergonic reaction is used to power an endergonic reaction.

Phosphorylation

The transfer of a phosphate group from ATP to another molecule to provide energy.

Enzyme

A molecule that catalyzes a chemical reaction without being consumed by the reaction.

Substrates

The reactants of a chemical reaction that are catalyzed by an enzyme.

Enzyme Activity

The measure of the amount of product an enzyme produces in a certain amount of time.

Activation Energy (EA)

The minimum energy required to start a chemical reaction.

Transition State

A temporary state of maximum energy within a reaction.

Enzyme-Substrate Complex

Forms when the substrate binds to an enzyme at the active site.

Active Site

Specific region of an enzyme that binds substrates.

Cofactors

Non-protein substances required by some enzymes for catalysis to occur.

Coenzyme

An organic molecule cofactor derived from vitamins.

Enzyme Inhibitors

Compounds that interfere with and selectively inhibit the catalysis of specific enzymes.

Competitive Inhibitors

Compete with the substrate for binding in the enzyme's active site.

Noncompetitive Inhibitor

Bind to an allosteric site on the enzyme, not competing with the substrate.

Metabolism

All of an organism's chemical reactions.

Metabolic Pathways

Series of chemical reactions that alter a substrate multiple times before the final product.

Catabolic Pathways

Release energy by breaking down molecules into smaller ones.

Anabolic Pathways

Spend energy to build up larger molecules.

Negative Feedback

The final product of a metabolic pathway inhibits an earlier step in the same pathway.

Positive Feedback

The final product of a metabolic pathway stimulates an earlier step in the same pathway.