lecture 25 biochem

Catabolism

The metabolic process that breaks down molecules to obtain energy.

Acetyl-CoA

A central metabolite in the citric acid cycle that is derived from carbohydrates, fatty acids, and amino acids.

Citric Acid Cycle

Also known as the Krebs cycle or TCA cycle, it is a multistep process that converts acetyl groups into CO2 and produces NADH, FADH2, and GTP.

Pyruvate Dehydrogenase

A multi-enzyme complex that converts pyruvate into acetyl-CoA, releasing CO2 in the process.

NADH

A reduced coenzyme that carries electrons to the electron transport chain to help generate ATP.

Regulatory Mechanisms

Controls the activity of the citric acid cycle based on substrate availability and product inhibition.

Covalent Modification

A regulatory process involving the addition or removal of chemical groups to proteins, affecting their activity.

Oxidative Decarboxylation

An irreversible oxidation process that removes a carboxyl group, producing CO2.

Substrate Channeling

The direct transfer of reaction intermediates between enzymes without releasing them into the solution.

Enzyme Complex

A group of enzymes that work together to efficiently catalyze a series of reactions.

GTP

A guanosine triphosphate, an energy currency similar to ATP, produced in the citric acid cycle.

Allosteric Effects

Regulatory effects that occur when a molecule binds to an enzyme at a site other than the active site, changing its activity.

Phosphorylation

The addition of a phosphate group to a molecule, often used to regulate enzyme activity.

Coenzyme A (CoA)

A coenzyme that carries acyl groups in metabolic reactions.

Flux

The rate of flow of metabolites through a metabolic pathway.

Citrate Synthase

The enzyme that catalyzes the formation of citrate from acetyl-CoA and oxaloacetate.

Isocitrate

An intermediate in the citric acid cycle formed from citrate by the enzyme aconitase.

Energy Conservation

The process by which energy released from reactions is stored in high-energy compounds like NADH and FADH2.

Competitive Inhibitor

A molecule that resembles a substrate and competes for binding at the enzyme's active site.

Krebs Cycle

Another name for the citric acid cycle, named after Hans Krebs.