Lecture 31 - Pentose Phosphate Pathway Flashcards
Reduced NADPH in red blood cells may lead to hemolytic anemia. Anemia occurs when glutathione is not reduced, causing oxidative stress on the RBC plasma membranes. What enzyme is deficient in this condition?
A. Glutathione reductase
B. Glucose-6-Phosphate dehydrogenase
C. Lactonase
D. 6-phosphogluconate dehydrogenase
B. G-6-PDH
The rate limiting step of the PPP is the production of _____ from ______.
ribulose-6-P from G-6-P (catalyzed by G-6-PDH)
What step of the PPP is oxidative?
The production of NADPH when G-6-P is formed into ribulose-6-P.
A cell requires more ribose-5-phosphate than NADH. What mode is it, and what process will be undertaken?
Mode 1; nucleotide synthesis
A cell requires more NADPH than ribose-5-Phosphate. What mode is the cell in, and what process will it undergo?
Mode 3; FA synthesis
A cell requires both NADPH and ATP. What mode is the cell in, and what process will it undergo?
Mode 4; glycolysis to produce pyruvate -> TCA -> large ATP production
A cell requires equal amounts of NADPH and ribulose-5-Phosphate. What mode is the cell in, and what will the cell produce?
Mode 2; DNA and FA synthesis
The pentose phosphate pathway produces _____, a molecule important in reductive biosynthesis (like cholesterol synthesis).
A. NADH
B. FADH2
C. NADPH
D. FMNH2
C. NADPH
Explain the pathology of hemolysis in G-6-PD deficiency.
G-6-PD cataylzes the reaction of G-6-P to Ribulose-5-P using G-6-PD. It also produces NADPH.
[NADPH] is lowered in G-6-PD deficiency. NADPH is important of the reduction of glutathione. When glutathione remains oxidized (Cys-S-S-Cys), it damages the integrity of RBC membranes.
The rate limiting step of the PPP is controlled by _______.
G-6-PD
NADPH produced by the oxidative phase of the PPP can be used for what two major biochemical pathways?
Fatty acid synthesis and glutathione reduction
The non-oxidative phase of the PPP produces _____ for glycolysis.
pyruvate
