Flashcards in Citric Acid Cycle Deck (17)
What are the three main precursors for acetyl CoA?
Pyruvate: from glycolysis
Fatty acids: from triglycerides
Amino Acids: from protein
What are the three destinations for acetyl CoA?
TCA cycle: for ATP generation
Ketone bodies: only in the liver during starvation
Sterols and fatty acids: primarily in the liver and adipose tissue
Where is acetyl CoA made?
The mitochondrial matrix
What is the universal carrier of acyl groups?
The oxidation of acetyl CoA leads to the production of what?
NADH, FADH2, and GTP
Where does the citric acid cycle take place?
Primarily in the mitochondrial matrix.
What are two ways that acetyl CoA can get into the mitochondrial matrix?
1) as pyruvate
2) As fatty acetyl CoA
After exiting the CAC and going through the ETC, how many ATPs are generated?
What is the point of the citric acid cycle?
The TCA cycle generates high energy phosphates (NADH, FADH2, GTP) that can then be oxidized to produce ATP in the electron transport chain
The TCA cycle also generates intermediates for other biosynthetic reactions -- it is a source of precursors for amino acids, fatty acids, and glucose synthesis
Differentiate course control vs. fine control of the citric acid cycle
Course control: levels of ADP, acetyl CoA and oxaloacetate levels
Fine control: allosteric effectors (ADP, Ca2+, NADH, etc)
What stimulates the CAC?
High levels of ADP and calcium (low energy markers)
What inhibits CAC?
High concentrations of ATP, GTP and NADH
What is pyruvate dehydrogenase deficiency?
Inability to convert pyruvate to acetyl CoA
What is the most common form of pyruvate dehydrogenase deficiency?
mutations in the E1 alpha gene
How is the most common form of PDH inherited?
X-linked dominant manner
What substances are elevated in the blood of children with PDH deficiency?
lactate, pyruvate and alanine
This produces a chronic lactic acidosis