One of the uses of NADPH in the cell is to prevent oxidative stress.
The major role of NADPH in red cells is to reduce the disulfide form of glutathione to the sulfhydryl form. The enzyme that catalyzes the regeneration of reduced glutathione, the flavoprotein glutathione reductase, a dimer of 50-kd subunits, is homologous to ferredoxin-NADP+ reductase, which we encountered in photosynthesis (Section 19.3.4). The reduced form of glutathione serves as a sulfhydryl buffer that maintains the cysteine residues of hemoglobin and other red-blood-cell proteins in the reduced state. Normally, the ratio of the reduced to oxidized forms of glutathione in red blood cells is 500.
Given the roles of NAD+ NADH in oxidation reactions and NADPH- NADP+ reduction reactions, discuss which cofactor is more commonly used in catabolic pathways and which one is in anabolic pathways? What do you expect the intracellular ratios of NAD+/NADH and NADP+/NADPH to be high or low under homeostasis? Explain your answers. Explain the benefits of the Q cycle comparing to direct transfer of electrons from QH2 to two cytochrome c Distinguish substrate-level phosphorylation and oxidative phosphorylation. Provide specific examples...
Which of the following is the electron carrier produced in the pentose phosphate pathway? NADH NADPH ubiquinone cytochrome C FADH2
In chloroplasts, glyceraldehyde 3-phosphate dehydrogenase uses NADPH as a cofactor in the synthesis of glucose. In cytoplasmic gluconeogenesis, however, the isozyme of this dehydrogenase uses NADH. Why is it advantageous for the enzyme in the chloroplast to use NADPH? : NADPH is abundant in chloroplasts, because it is generated by the light reactions. NADPH provides more reducing power than NADH in cells. NADPH is harmful to chloroplasts when levels become too high. The presence of NADH increases the rate of...
Which of the following does NOT undergo oxidation-reduction reactions? A. ATP B. NADH C. NADPH D. FAD
In a standard assay for LDH activity we used a phosphate buffer, pyruvate, and NADH with the LDH enzyme. I don't understand what happens when we replace the NADH with NADPH and why does LDH have a preference for NADH over NADPH
In a cell, why must NADH be reoxidized? How does this happen in an organism that uses respiration? Fermentation? 2. Explain the chemiosmotic mechanism of ATP generation. How does oxidative phosphorylation compare with substrate level phosphorylation found in glycolysis and the Kreb’s cycle? 3. Which of the following yields the greatest energy for a cell: fermentation, anaerobic respiration, or aerobic respiration? Which yields the least? Why? 4. Explain what happens to glucose during glycolysis and respiration in terms of oxidation...
In a cell, why must NADH be reoxidized? How does this happen in an organism that uses respiration? Fermentation? 2. Explain the chemiosmotic mechanism of ATP generation. How does oxidative phosphorylation compare with substrate level phosphorylation found in glycolysis and the Kreb’s cycle? 3. Which of the following yields the greatest energy for a cell: fermentation, anaerobic respiration, or aerobic respiration? Which yields the least? Why? 4. Explain what happens to glucose during glycolysis and respiration in terms of oxidation...
glutathione reductase catalyzes the following reaction: GSSG (oxidized glutathione) + NADPH+H ----> 2GSH (reduced Glutathione)+ NADP+. NAD+ + H + 2e --> NADH E= -0.32 V NADP+ + H + 2e NADPH E= -0.32 V GSSG + + 2H + 2e 2GSH E= -0.23 V a) Calculate delta G for glutathione reductase reaction in the direction shown using E values above b) Suppose that a cell contained an isoform of glutathione reductase that used NADH instead of NADPH...
How many NADPH are required to make one molecule of palmitic acid from acetyl CoA? a. 7 b. 8 c. 14 d. 16 e. 21
Show how NADH is recycled to NAD+ under anaerobic conditions. Why is it important to recycle NADH produced during glycolysis to NAD+?