The Citric Acid Cycle II and the Pentose Phosphate Pathway

These flashcards cover the key vocabulary terms and concepts from the lecture on the Citric Acid Cycle and the Pentose Phosphate Pathway, aiding in exam preparation.

Citric Acid Cycle

A metabolic pathway that breaks down acetyl-CoA to produce energy, NADH, FADH2, and GTP while releasing CO2.

Acetyl-CoA

A central metabolite that enters the citric acid cycle, formed from the decarboxylation of pyruvate.

NADH

A reduced form of NAD+ that serves as an electron donor in the electron transport chain.

GTP

Guanosine triphosphate, a molecule that provides energy for cellular processes, produced in the citric acid cycle.

Oxidative Reactions

Reactions in the pentose phosphate pathway that produce NADPH and ribulose-5-phosphate.

Transketolase

An enzyme that transfers two-carbon units in the pentose phosphate pathway.

Transaldolase

An enzyme that transfers three-carbon units in the pentose phosphate pathway.

Glucose-6-Phosphate Dehydrogenase

An enzyme that catalyzes the first step in the pentose phosphate pathway, producing NADPH.

NADPH

A cofactor used in anabolic reactions and an important reducing agent in biochemistry.

Fumarate

A product of the citric acid cycle that is converted to malate by the fumarase enzyme.

Regulation of Citric Acid Cycle

Controlled by substrate availability and energy status, involving key enzymes like citrate synthase and isocitrate dehydrogenase.

Malate Dehydrogenase

An enzyme that catalyzes the conversion of malate to oxaloacetate in the citric acid cycle, producing NADH.

Glycolysis

The metabolic pathway that converts glucose into pyruvate, yielding ATP and NADH.

Pentose Phosphate Pathway

A metabolic pathway parallel to glycolysis that generates NADPH and pentoses.

Glutathione

A tripeptide that acts as an antioxidant and thiol donor, protecting cells from oxidative stress.

Erythrocyte Integrity

The maintenance of red blood cell structure and function, which can be compromised by glutathione depletion.

Primaquine

An antimalarial drug that can cause hemolytic anemia in individuals with glucose-6-phosphate dehydrogenase deficiency.

Pyruvate Dehydrogenase Complex

A multi-enzyme complex that converts pyruvate to acetyl-CoA, linking glycolysis and the citric acid cycle.

Amino Acid Metabolism

The process by which amino acids are used for energy production and as substrates for synthesis of other compounds.

Calcium Ions (Ca2+)

Signifiers of energy demand in the citric acid cycle and involved in the regulation of several cycle enzymes.

GTP Production

The process in which succinyl-CoA synthetase generates GTP from succinyl-CoA in the citric acid cycle.