Metabolism and Energy Flow in Biological Systems

A set of vocabulary flashcards for students to study key concepts related to metabolism, energy flow, thermodynamics, and enzymatic reactions.

Metabolism

The totality of an organism's chemical reactions, arising from interactions between molecules within the cell.

Anabolic Pathways

Metabolic pathways that require energy to build complex molecules from simpler ones.

Catabolic Pathways

Metabolic pathways that release energy by breaking down complex molecules into simpler ones.

Bioenergetics

The study of how energy flows through living organisms.

Kinetic Energy

Energy of objects in motion.

Potential Energy

Stored energy that can be converted into kinetic energy.

Thermodynamics

The branch of physics that deals with heat and temperature and their relation to energy and work.

First Law of Thermodynamics

The total energy of the universe is constant; energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

The disorder (entropy) of the universe is always increasing.

Gibbs Free Energy (G)

The energy available to do work in a system, defined by the equation G = H - TS.

Exergonic Reaction

A reaction that releases energy; Gibbs free energy change (ΔG) is negative.

Endergonic Reaction

A reaction that requires energy input; Gibbs free energy change (ΔG) is positive.

Redox Reactions

Chemical reactions that involve the transfer of electrons; oxidation and reduction processes are coupled.

Enzymes

Proteins that catalyze biochemical reactions by lowering the activation energy needed for reactions to occur.

Active Site

The region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Cofactors

Inorganic ions that assist enzymes in catalyzing reactions.

Coenzymes

Organic molecules that serve as electron donors or acceptors in redox reactions.

Competitive Inhibition

A form of enzyme inhibition where an inhibitor competes with the substrate for binding to the active site.

Allosteric Regulation

The regulation of an enzyme by binding an effector molecule at a site other than the active site, causing a change in shape.

Energy Currency of Cells

ATP (Adenosine triphosphate) is the primary energy carrier in cells.

Phosphorylation

The addition of a phosphate group to a molecule, often used to transfer energy.

Hydrolysis of ATP

The reaction that breaks down ATP into ADP and inorganic phosphate, releasing energy.

Activation Energy

The minimum energy required to start a chemical reaction.