Lecture 28 - TCA Cycle Flashcards
The f(X) portion of Acetyl-CoA is the ______.
A. Adenine molecule
B. Phosphate portion
C. Sulfated carbonyl group
C. Sulfated carbonyl
ATP production occurs in the _______ of the mitochondria.
Matrix
Electrons are transferred between compounds via what molecules?
A. CO2 and H2O
B. CO2 and FAD
C. NADH and FADH2
C. NADH and FADH2
The production of _____ from _____ is the only producer of nucleotide Triphosphates in the TCA cycle.
Succinate from succinylCoA
In oxidative phosphorylation, electrons are used to reduce \_\_\_\_\_. A. NAD+ B. O2 C. FADH D. CO2
B. O2
The high energy elections formed by the TCA cycle produces _____ in the intermembrane space via the electron transport chain.
H+ gradient
Compartmentalization of the Kreb's cycle occurs by moving pyruvate into. A. Cytosol B. Mitochondria C. Nucleus D. Golgi
B. Mitochondria
Pyruvate dehydrogenase is important in the ___________ of pyruvate. It it requires __________ as a prosthetic group.
oxidative decarboxylation of pyruvate; TPP
The dihydrolipoyl portion of pyruvate dehydrogenase is important in the ___________. It it requires __________ as a prosthetic group.
transfer of acetyl group to CoA; Lipoamide
Dihydrolipoyl dehydrogenase is important in the ___________. It it requires __________ as a prosthetic group.
regeneration of oxidized lipoamide; FAD
Catalytic co-factors are prosthetic groups for formation of acetyl-CoA by pyruvate dehydrogenase. What are the catalytic cofactors?
TPP; lipoic acid; FAD
Pyruvate dehydrogenase requires cofactors that function as substrate. What are they?
CoA and NAD
What is a “stoichiometric cofactor?
A cofactor that acts as a substrate
Production of acetyl-CoA occurs where? A. Intermembrane space B. Mitochondrial matrix C. On the outer mitochondrial membrane D. On the inner mitochondrial membrane
B. Mitochondrial matrix
Production of Acetyl-CoA from pyruvate occurs in three steps. What are they?
1) Decarboxylation of pyruvate to form CO2
2) Oxidation of acetyl group
3) Transfer of acetyl group to CoA
lipoamide is found on what domain of the PDH complex?
A. E1
B. E2
C. E3
B. E2
Regeneration of the lipoamide molecule requires the addition of what cofactor?
FAD, which becomes FADH2
FAD is produced after the regeneration of lipoamide. What are the other products of this reaction?
NADH and H+ (high e- electrons that go into the ETC)
Draw the PDH complex. Include the stochiometric cofactors, catalytic cofactors, and the reactions.
Place the picture here.
The reoxidation of the lipoamide chain occurs in what PDH subunit? A. E1 B. E2 C. E3 D. All of the above
E3
Which stoichiometric cofactor "visits" each subunit? A. NAD+ B. FAD C. Lipoamide D. TPP
C. Lipoamide
_____ activates pyruvate dehydrogenase phosphatases. This results in increased PDH activity.
ADP and pyruvate; ADP indicates a low energy charge and pyruvate is a PDH substrate
______ acts to activate pyruvate dehydrogenase kinase, which decreases PDH activity
Acetyl-CoA; acetyl-CoA is an end product of PDH
Isocitrate dehydrogenase is important to the production of isocitrate from citrate. Why is this important in the TCA cycle? What enzyme is used?
Citrate is NOT able to undergo the decarboxylation to alpha-KG. Isocitrate, however, is.
Aconitase is the enzyme
(-) regulation of IDH
ATP; NADH (end products of TCA)
(+) regulation of IDH
ADP (indicates low E*, and requires “jump-starting” TCA cycle)
What steps produces NADH/CO2?
Isocitrate->alpha-ketogluterate;
alpha-ketogluterate-> succinyl-CoA
What steps produce NADH only?
Malate to oxaloacetate
What steps produce GTP?
Succinyl-CoA —> Succinate
What step produces FADH2?
Succinate —> Fumarate
Like PDH, alpha-ketoglutarate dehydrogenase joins the product of the reaction to ____.
CoA
The final four steps of the TCA cycle are responsible for ___.
Regeneration of oxaloacetate
Oxaloacetate regeneration converts a methylene in fumarate to ________ in oxaloacetate.
carbonyl
High energy electrons are released from enzymes in all steps of the TCA cycle except:
A. Succinyl CoA to Succinate with ATP generation
B. Succinate to Fumarate with FADH2 production
C. Malate to Oxaloacetate with NADH production
D. Isocitrate to alpha-ketoglutarate with NADH production
A.
Malate oxidation to oxaloacetate has a + deltaG. How is this overcome?
- By the movement of NADH into the ETC
- By the use of oxaloacetate to form citrate (by citrate synthase)
