Quiz 9- Citric Acid Cycle

These flashcards cover key terms and concepts related to the Citric Acid Cycle, including enzymes, reactions, and their significance in metabolism.

Citric Acid Cycle

Also known as the TCA or Krebs Cycle, it oxidizes acetyl-CoA to generate CO₂ and high-energy electron carriers.

Substrate-level phosphorylation

A process where ATP or GTP is produced directly in a metabolic pathway, specifically by Succinyl-CoA synthetase in the TCA cycle.

Oxaloacetate

A four-carbon molecule that combines with Acetyl-CoA to form citrate in the first step of the citric acid cycle.

Isocitrate dehydrogenase

An enzyme that catalyzes the conversion of isocitrate to alpha-ketoglutarate, producing NADH in the process.

Aconitase

An enzyme that catalyzes the stereospecific isomerization of citrate to isocitrate through cis-aconitate.

Alpha-Ketoglutarate dehydrogenase

An important enzyme in the citric acid cycle transforming alpha-ketoglutarate into succinyl-CoA, producing NADH.

Fumarase

The enzyme that catalyzes the conversion of fumarate to L-malate, involving hydration of the alkene.

Succinyl-CoA synthetase

An enzyme that catalyzes the conversion of succinyl-CoA to succinate, generating ATP or GTP.

Malate dehydrogenase

An enzyme that converts malate back to oxaloacetate, producing NADH in the process.

NADH

A high-energy electron carrier produced during various steps of the citric acid cycle, essential for cellular respiration.

FADH₂

Another high-energy electron carrier produced specifically during the oxidation of succinate to fumarate.

Fluoroacetate

A compound that inhibits the enzyme aconitase in the citric acid cycle.

GTP/ATP equivalents

The total energy currency produced in the citric acid cycle, approximately 10 ATP per acetyl-CoA.

Decarboxylation

The biochemical process of removing a carboxyl group, resulting in the release of CO₂, as seen in the conversion of isocitrate to alpha-ketoglutarate.

High-energy intermediates

Compounds such as NADH and FADH₂ that store energy used to generate ATP in oxidative phosphorylation.