2.2 Glucose Metabolism and Cellular Respiration

This set of vocabulary flashcards covers the fundamental concepts, enzymes, and pathways involved in glucose metabolism, including glycolysis, the Krebs cycle, fermentation, and the electron transport chain.

Glucose

A sugar molecule most often utilized by cells to generate ATP or energy.

ATP (Adenosine Triphosphate)

An activated carrier of energy used by cells for metabolic reactions, growth, maintenance of tissues, and healing.

Metabolism

The sum total of all chemical reactions occurring within a cell, categorized into catabolic and anabolic groups.

Catabolism

Metabolic reactions that break down nutrients to release energy stored in chemical bonds and produce precursor molecules for anabolism.

Anabolism

The building up of larger macromolecules and cellular structures, which requires the expenditure of energy (currency).

Cellular Respiration

A set of oxidation-reduction (redox) reactions that oxidize nutrients to produce energy or ATP

Aerobic Pathway

Metabolic reactions, such as the later stages of cellular respiration, that eventually require oxygen to generate ATP.

Glycolysis

The first stage of respiration, occurring in the cytoplasm, which involves splitting one molecule of glucose into two molecules of pyruvate; this process is anaerobic.

Hexokinase

The enzyme that catalyzes the phosphorylation of glucose to form glucose 6-phosphate during the first step of glycolysis.

Glucose 6-phosphate

A specialized molecule formed in the first step of glycolysis that prevents glucose from leaving the cell and dedicates it to the glycolytic pathway.

Pyruvate

A three-carbon product of glycolysis; two molecules of pyruvate are produced from one molecule of glucose.

NADH

An energy carrier produced during glycolysis and the Krebs cycle that carries high-energy electrons to the electron transport chain.

Fermentation

An anaerobic pathway utilized to oxidize NADH back to NAD so that glycolysis can continue in the absence of oxygen.

Alcoholic Fermentation

A fermentation pathway where ethanol acts as the electron acceptor, producing alcohol and CO2 as waste products, commonly seen in yeast.

Lactic Acid Fermentation

A fermentation pathway where pyruvate acts as the electron acceptor, producing lactic acid as a waste product, occurring in skeletal muscle cells.

Acetyl Coenzyme A (acetyl CoA)

An intermediate molecule formed from pyruvate after an intermediate step that enters the Krebs cycle.

Krebs Cycle

Also known as the TCA (tricarboxylic acid cycle) or citric acid cycle; a series of eight enzyme-catalyzed reactions in the mitochondrial matrix that generate energy carriers.

FADH₂

An energy carrier produced specifically during the Krebs cycle that delivers electrons to the electron transport chain.

Electron Transport Chain (ETC)

A series of membrane-bound proteins that pass electrons through redox reactions to create a proton gradient for ATP production.

Chemiosmosis

The process of setting up a chemical gradient (proton gradient) across a semipermeable membrane to drive cellular work.

ATP Synthase

An enzyme and rotor-like protein that catalyzes the synthesis of ATP from ADP and phosphate using the kinetic energy of flowing hydrogen ions.

Proton Motive Force

The potential energy gradient created by the concentration of positive hydrogen ions on one side of the inner mitochondrial membrane.

Oxidative Phosphorylation

The production of ATP using energy derived from the redox reactions of the electron transport chain and a proton gradient.

Substrate-level Phosphorylation

A type of phosphorylation where a phosphate group is transferred directly to ADP to form ATP, occurring in glycolysis and the Krebs cycle.

38 ATP

The maximum net yield of ATP molecules produced from the aerobic respiration of one glucose molecule in prokaryotic cells.

36 ATP

The typical net yield of ATP molecules produced from the aerobic respiration of one glucose molecule in eukaryotic cells.