Cellular Respiration: Pyruvate Oxidation and the Krebs Cycle

Vocabulary flashcards covering the stages of cellular respiration shown in the text: pyruvate oxidation to acetyl-CoA and the reactions and yields of the Krebs (citric acid) cycle.

Pyruvate Oxidation

The reaction linking glycolysis to the Krebs cycle, during which a molecule of $CO_2$ is removed from pyruvate to form a 2-carbon compound, reducing $NAD^+$ to $NADH$, and attaching to Coenzyme A.

Acetyl-CoA (Acetyl Coenzyme A)

A 2-carbon compound formed when the oxidized 2-carbon product of pyruvate attaches to Coenzyme A ($CoA$).

Krebs Cycle

A cyclic metabolic pathway occurring in the mitochondrial matrix, also known as the Citric Acid Cycle, named after the scientist who contributed to its discovery.

Mitochondrial Matrix

The location inside the mitochondria where the reactions of the Krebs cycle take place.

Oxaloacetate

A 4-carbon compound that combines with the 2-carbon acetyl-CoA to initiate the Krebs cycle and is regenerated at the end of the cycle.

Citrate

A 6-carbon compound formed at the start of the Krebs cycle by the reaction between acetyl-CoA and oxaloacetate.

Products of Pyruvate Oxidation (per 1 pyruvate)

One molecule of carbon dioxide ($CO_2$), one molecule of $NADH$, and one molecule of acetyl-CoA.

Yield of One Krebs Cycle Turn

Two molecules of $CO_2$, three molecules of $NADH$, one molecule of $FADH_2$, and one molecule of $ATP$ produced directly.

Krebs Cycle Turns per Glucose Molecule

Two complete turns of the cycle, because one molecule of glucose yields two molecules of acetyl-CoA.