BMS1030 - CHO metabolism - TCA cycle and OP Flashcards
(23 cards)
What is the TCA cycle fed by?
What molecules is energy generated through?
What are the TCA cycle intermediates also used for?
Products of CHO, Lipid and Protein
Energy generated through NADH, FADH and GTP
Intermediates used for biosynthesis of AAs and other metabolites.
What is the link between glycolysis and the TCA cycle?
Pyruvate carriage across mitochondrial membrane
Conversion of pyruvate (3C) to Acetyl CoA (2C)
What is required to turn pyruvate to Acetyl CoA?
CoA, enzyme (pyruvate dehydrogenase), thiamin and riboflavin (B vitamins) and NAD+
Riboflavin is a ________ to FAD
Precursor
Where do you find Mitochondrial Pyruvate carriers? What is their function? How does Pyruvate get across the first membrane?
In the inner mitochondrial membrane. Needed to transport pyruvate across membrane and into the matrix of mitochondria.
Facilitated diffusion across outer membrane.
The conversion of pyruvate to AcetylCoA is _____________, therefore it is a commital step.
What causes the change from a 3C to 2C molecule?
Where is this 2 C skeleton derived from?
Irreversible.
Loss of CO2
2 carbon skeleton, derived from:
* Carbohydrate (glycolysis)
* Fatty acids (b oxidation)
* Amino acids
What are a couple of examples of what inhibits or activates pyruvate dehydrogenase?
Inhbited by: ATP, ActeylCoA, NAD+
Activated by: Insulin, AMP, NADH
DONT NEED TO KNOW, JUST APPRECIATE ITS A HEABILY CONTROLLED ENZYME AS IT IS AN IRREVERSIBLE STEP
Where does Glycolysis and anaerobic catabolism of CHO occur?
Where does TCA occur?
Where does Oxidative phosphorylation occur?
In the cytosol
Mitochondrial matrix
On the mitochondrial inner membrane
What electron carriers carry electrons to the respiratory chain?
FAD+ and NAD+
Give an overview of the TCA cycle.
- what are the changes in numbers if Cs
- what molecules are produced along the way?
NAD+ -> NADH
FAD+ -> FADH2
GDP + Pi -> GTP
What is the first step in the TCA cycle?
2C + 4C -> 6C
What is the second step in the TCA cycle?
Citrate -> Isocitrate using Aonitase enzyme
Changing formation
What is the third step in the TCA cycle?
6C – -CO2 -NADH –> 5C
What is the 4th step of the TCA cycle?
5C – -CO2 -NADH –> 4C
Steps 5-8 of the TCA cycle. What is the beginning and end result? What is produced and used?
Begins with Succinyl-CoA. Ends with Oxatoacetate.
Uses GDP + Pi, FAD+ and NAD+
Prouces 1GTP, 1FADH2 and 1NADH
In one turn of the TCA cycle, what is produced?
3 NADH, 1 FADH and 1 GTP (and 2 CO2)
What is the TCA cycle dependant on?
Supply of Acteyl Coa, NAD+ and FAD+.
What 3 controlled 3 irreversile reactions are involved with the TCA cycle?
- Citrate synthase (step 1)
- Isocitrate dehydrogenase (step 3)
- Alpha-ketoglutare dehydrogenase (step 4)
What do Anaplerotic reactions do?
Maintain constant levels of TCA intermediates.
What do Cateplerotic reactions do?
Utilize TCA intermediates for biosynthetic pathways
How can pyruvate be converted straight to Oxaloacetate? Why is this needed?
(Oxaloacetate can be used to form AAs)
