Energy Flow and Metabolism in Cells

These flashcards cover vocabulary and key concepts related to energy flow and metabolism in cells, including thermodynamics, cellular respiration, enzymatic activity, and energy transformations.

Energy

The ability to do work or bring about change.

Kinetic Energy

The energy of motion.

Potential Energy

Stored energy, such as that found in food.

Thermodynamics

The study of the flow and transformation of energy.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

Energy transformations are not 100% efficient, and some energy is lost as heat.

Entropy

The degree of disorder in a system.

Metabolism

The sum of all chemical reactions occurring in a cell.

Catabolism

The breakdown of molecules.

Anabolism

The building up of molecules.

Free Energy (ΔG)

The amount of energy available for work in a system.

Exergonic Reaction

A spontaneous reaction that releases energy.

Endergonic Reaction

A reaction that requires an input of energy.

ATP (Adenosine Triphosphate)

The main energy currency of cells.

Coupled Reactions

Reactions where the energy from an exergonic reaction drives an endergonic reaction.

Enzyme

A protein that acts as a catalyst to speed up chemical reactions.

Substrate

The reactant that an enzyme acts upon.

Coenzymes

Organic nonprotein molecules that assist enzymes in reactions.

Oxidation-Reduction Reactions (Redox)

Reactions involving the loss and gain of electrons.

Photosynthesis

The process by which chloroplasts convert solar energy to chemical energy in carbohydrates.

Cellular Respiration

The process of converting glucose and oxygen into energy (ATP), carbon dioxide, and water.

Glycolysis

The breakdown of glucose into pyruvate, producing ATP.

Fermentation

An anaerobic process that converts glucose into ATP and produces by-products such as lactic acid or alcohol.

Citric Acid Cycle

A cyclical series of reactions that oxidizes acetyl CoA and generates ATP and electron carriers.

Electron Transport Chain

A series of proteins that transfer electrons, creating a proton gradient to drive ATP synthesis.