Tricarboxylic Acid Cycle Flashcards
Names of the Tricarboxylic Acid Cycle
TCA Cycle, Krebs Cycle, Citric acid cycle
TCA is the final pathway where the ___________ of __________, ________, and ________ converge and their carbon skeletons being converted to _____.
Catabolism, carbohydrates, amino acids, fatty acids, CO2
Catabolic Pathways of TCA
Breakdown of some amino acids provides certain TCA cycle intermediates
Anabolic Pathways of TCA
Some TCA cycle intermediates feed into biosynthetic pathways, such as the synthesis of certain amino acids
What two molecules provide most of the energy, due to the terminal oxidation of all biomolecules?
NADH & FADH2
What is the TCA cycle coupled with? Mainly referring to the oxidative phosphorylation of the reduced carriers (NADH and FADH2)
Production of ATP in the ETC
where is the TCA cycle located?
The mitochondrial matrix (close to the ETC)
Linear Metabolic Pathway
Starts with 1 metabolite and ends up with a different one (glycolysis)
Cycle
starts with a certain metabolite that undergoes multiple steps forming different intermediates…but in the end the same initial metabolite is regenerated.
No net loss, no net gain.
Aka why it’s a CYCLE
Reaction required prior to TCA
Oxidative phosphorylation of pyruvate
steps of Oxidative Phosphorylation of Pyruvate
- Transported into the mitochondria
- by a mitochondrial pyruvate carrier or limited simple diffusion - Converted into Acetyl CoA by Pyruvate dehydrogenase complex
- often called PDH - CO2 must be released and NADH must be produced
What transports Pyruvate into the mitochondria?
Mitochondrial Pyruvate carrier
Or
Limited simple diffusion
What enzyme converts Pyruvate into Acetyl CoA?
Pyruvate Dehydrogenase (complex) or PDH
PDH
Protein aggregate of 3 separate enzymes:
E1: P-carboxylase
E2: dihydrolipoyl transacetylase
E3: dihydrolipoyl dehydrogenase
Cofactors of PDH
Thiamine pyrophosphate, TPP Lipoma idle Coenzyme A (CoA) FAD NAD+
