Universal Electron Acceptors: A Comprehensive Review in Question and Answer Format for USMLE Step

Описание: https://usmleqa.com/?p=9383
Question: What are universal electron acceptors?
Answer: Nicotinamides (NAD+, NADP+ from vitamin B3) and flavin nucleotides (FAD from vitamin B2).Question: What is the general use of NAD+?
Answer: NAD+ is generally used in catabolic processes to carry reducing equivalents away as NADH.Question: What is NADPH used for?
Answer: NADPH is used in anabolic processes (eg, steroid and fatty acid synthesis) as a supply of reducing equivalents.Question: What is NADPH a product of?
Answer: NADPH is a product of the HMP shunt.Question: What are some of the uses of NADPH?
Answer: NADPH is used in anabolic processes, respiratory burst, Cytochrome P-450 system and Glutathione reductase. Question: What is the function of NADH?
Answer: NADH is used to transfer electrons and protons to the electron transport chain in the process of cellular respiration, where it is eventually converted back to NAD+ so that it can be used again.Question: What is the role of NADPH in anabolic processes?
Answer: NADPH is used in anabolic processes as a source of reducing equivalents, which are used to reduce molecules and drive reactions that synthesize molecules.Question: What is the role of NADPH in the respiratory burst?
Answer: NADPH is used in the respiratory burst, a process that occurs in certain white blood cells, to generate reactive oxygen species (ROS) which are used to kill invading microorganisms.Question: What is the role of NADPH in the Cytochrome P-450 system?
Answer: NADPH is used in the Cytochrome P-450 system, a group of enzymes that catalyze the oxidation of a wide range of substrates, as a source of reducing equivalents to drive the reactions.Question: What is the role of NADPH in Glutathione reductase?
Answer: NADPH is used in Glutathione reductase, an enzyme that catalyzes the reduction of oxidized glutathione, as a source of reducing equivalents to drive the reaction. Question: How does NAD+ participate in catabolic reactions?
Answer: NAD+ acts as an electron acceptor in catabolic reactions such as glycolysis and the citric acid cycle, accepting electrons from the molecules being broken down and becoming NADH.Question: What is the HMP shunt?
Answer: The HMP shunt, also known as the pentose phosphate pathway, is a metabolic pathway that generates NADPH and pentose sugars. It also provides an alternative source of energy for cells and is important in the synthesis of nucleic acids and lipids.Question: How does NADPH participate in anabolic reactions?
Answer: NADPH acts as an electron donor in anabolic reactions, providing electrons to molecules that are being synthesized. This can include the biosynthesis of fatty acids, steroids, and other molecules.Question: How does NADPH participate in the respiratory burst?
Answer: In the respiratory burst, NADPH is used to generate reactive oxygen species, which are used to kill invading microorganisms. This process is mediated by the enzyme NADPH oxidase, which uses NADPH as an electron donor to generate superoxide, a reactive oxygen species.Question: How does NADPH participate in the Cytochrome P-450 system?
Answer: In the Cytochrome P-450 system, NADPH is used as an electron donor to drive the reactions catalyzed by the enzymes. This can include the oxidation of a wide range of substrates, including drugs, toxins, and steroid hormones.Question: How does NADPH participate in Glutathione reductase?
Answer: In Glutathione reductase, NADPH is used as an electron donor to drive the reduction of oxidized glutathione. The enzyme catalyzes the transfer of electrons from NADPH to glutathione, reducing it back to its reduced form. This process helps to maintain the balance of reduced and oxidized glutathione in the cell, which is important for cellular antioxidant defense.tab