TRICARBOXYLIC ACID CYCLE

Tricarboxylic Acid Cycle (TCA Cycle)

Also known as the citric acid cycle or the Krebs cycle, it is a series of chemical reactions used by aerobic organisms to generate energy from acetyl-CoA.

Acetyl-CoA

A central metabolite that enters the TCA cycle, derived from carbohydrates, fats, and proteins.

NADH

Reduced form of nicotinamide adenine dinucleotide, generated during the TCA cycle and used in oxidative phosphorylation to produce ATP.

FADH2

Reduced form of flavin adenine dinucleotide, produced during the oxidation of succinate in the TCA cycle.

Oxaloacetate

A four-carbon compound that reacts with Acetyl-CoA to initiate the TCA cycle.

Citrate Synthase

An enzyme that catalyzes the reaction of Acetyl-CoA with oxaloacetate to form citrate.

Isocitrate

A six-carbon intermediate formed from rearranging citrate in the second step of the TCA cycle.

Alpha-ketoglutarate

A five-carbon compound formed from isocitrate after it loses carbon dioxide.

Succinyl-CoA

A four-carbon intermediate formed by the oxidative decarboxylation of alpha-ketoglutarate.

Guanosine Triphosphate (GTP)

A high-energy compound formed during the conversion of succinyl-CoA to succinate in the TCA cycle.

Electron Transport Chain (ETC)

The third stage of cellular respiration where NADH and FADH2 transfer energy to produce ATP.

Oxidative Phosphorylation

The process by which ATP is produced in the electron transport chain from the energy released by NADH and FADH2.

ATP Yield from TCA Cycle

Each complete turn of the cycle generates a total of 12 ATP from various energy carriers.

Enzyme

A biological catalyst that accelerates chemical reactions, with specific enzymes catalyzing each step of the TCA cycle.

Hydration

The addition of water to fumarate to form malate in the TCA cycle.