Chapter 6: Making Life Work (Energy Metabolism)

These flashcards cover key concepts related to energy metabolism as discussed in Chapter 6, including metabolic pathways, energy forms, and fundamental thermodynamic principles.

Metabolism

The sum of all chemical reactions in a living organism.

Anabolic Pathways

Metabolic pathways that assemble small molecules into large ones, requiring energy.

Catabolic Pathways

Metabolic pathways that break down large molecules into small ones, releasing energy.

Phototrophs

Organisms that harvest energy from sunlight.

Chemotrophs

Organisms that harvest energy from chemical compounds.

Autotrophs

Organisms that obtain their source of carbon from inorganic sources, such as CO2.

Heterotrophs

Organisms that obtain their source of carbon from organic compounds.

ATP (Adenosine Triphosphate)

The universal currency of cellular energy; provides energy for cellular processes.

Potential Energy

The energy that matter possesses due to its position or organization.

Kinetic Energy

The energy of motion.

Entropy (S)

A measure of disorder or randomness in a system.

First Law of Thermodynamics

Energy cannot be created or destroyed; it can only be transformed.

Second Law of Thermodynamics

Energy transformations result in an increase in entropy (disorder) in the universe.

Exergonic Reactions

Reactions that release energy; usually associated with catabolic processes.

Endergonic Reactions

Reactions that require energy input; usually associated with anabolic processes.

Energetic Coupling

The process of using energy released from exergonic reactions to drive endergonic reactions.

Gibbs Free Energy (G)

The energy available to do work in a system, calculated as G = H - T \cdot S. Here, H is enthalpy (the total heat content of the system), T is the absolute temperature, and S is entropy (the measure of disorder). The term T \cdot S represents the energy lost to disorder that is unavailable for work.

Hydrolysis of ATP

A reaction where ATP is broken down into ADP and inorganic phosphate, releasing energy.

Metabolic Pathway

A series of chemical reactions where the product of one reaction becomes the reactant of the next.

High energy phosphate bonds

Unstable bonds in ATP that store significant amounts of energy.