Energy Production-carbs 4 Flashcards
What is the role of pyruvate dehydrogenase in glucose metabolism?
It converts Pyruvate (3C molecule) into acetylCoA (2C molecule) to the enter the tricarboxylic acid/Krebs cycle.
What is released when Pyruvate becomes AcetylCoA? What does this mean for the reaction?
A CO2 is released, therefore an irreversible reaction.
Describe some factors of the Krebs cycle.
A single pathway Catabolism of sugars, fatty acid, ketone bodies,amino acids and alcohol Produces molecules that readily lose CO2 Oxidises carbons from acetate to CO2 Oxidative producing NADH and FADH2 Some energy produced as GTP Produce precursors for biosynth Not function in O2 absence Intermediates act catalytically
What happens in the Krebbs cycle? (Overview not specific details)?
ACetylCoA joins a C4 molecule to form citrate (C6)
CO2 is released twice for every acetylCoA
Reaction of NAD and FAD occur
Phosphorylation of GDP to GTP X2
CoA is released
6 NADH released
2 FADH2 releases
What is the Krebbs/TCA cycle regulated by?
Regulated by energy availability like glycolysi
The product succinylcholine-CoA inhibits it
Inhibited by high levels ATP/acetyl-CoA/NADH/citrate
Activated by high levels of pyruvate/insulin/CoASH/ADP
Where does the TCA/Krebbs cycle occur?
In the mitochondrial matrix
Where do electrons travel in the electron transport chain?
From the mitochondrial matrix through the inner mitochondrial membrane, losing energy as they ass down the electron carriers.
What happens to the energy released by the e- transport chain?
30% of it is used to transport H+ molecules across the membrane into the inter membrane space to create a gradient.
The rest is lost as heat to keep the body warm
Where do the e- and H+ come from in the electron transport chain?
NADH + H+(2H+ =2e-) turns to NAD+
Where do the electrons format he transport chain go?
They join 2H+ and one O to form H2O.
What is the proton motive force?
The energy that e- provides to push H+ across the inner mitochondrial membrane and make a gradient.
Why do proteins return to the matrix?
It’s favoured energetically by the electrochemical gradient (electrical and chemical gradient)
How do H+ cross the mitochondral membrane?
They are forced through ATP Synthase becase the membrane is highly impermeable. This drives ATP synthesis.
How is oxidative phosphorylation regulated?
When ATP is high, there is low ADP so no substrate for ATP synthesis.
Inward flow of H+ into matrix stops
Conc of H+ in intermembrane space is high
Prevents further H+ pumping, as electron energy not enough to overcome high conc gradient.
Less NADH is used up this circles back and stops other glycolysis pathways.
How do inhibitors stop oxidative phosphorylation?
Cyanide inhibitors block the electron transport.
Stops acceptance of electrons by O2.
Transport chain stops as electrons back up
H+ pumping stops
