Untitled Deck Flashcards
(20 cards)
What is the pentose phosphate pathway also known as?
The pentose phosphate pathway is also known as the pentose shunt, hexose monophosphate shunt, or phosphogluconate pathway.
Where does the pentose phosphate pathway occur?
The pentose phosphate pathway occurs in the cytosol of the cell.
What is one fate of glucose 6-phosphate (G6P)?
One fate of glucose 6-phosphate (G6P) is the pentose pathway.
What intermediates does the pentose pathway produce?
The pentose pathway produces glyceraldehyde 3-phosphate and fructose 6-phosphate.
What are the two main purposes of the pentose phosphate pathway?
The two main purposes are to yield NADPH for anabolic reactions and to yield ribose 5-phosphate for nucleotide biosynthesis.
What is NADPH used for?
NADPH is used in anabolic reactions requiring electrons, such as fatty acid and cholesterol biosynthesis.
How does NADPH differ from NADH?
NADPH is a phosphorylated form of NADH, used for synthetic reactions, while NADH drives the phosphorylation of ADP to ATP.
What are the two phases of the pentose pathway?
The two phases are Phase 1: Oxidative reactions and Phase 2: Non-oxidative interconversion of sugars.
What occurs in the oxidative stage of the pentose pathway?
The oxidative stage involves reactions that form NADPH + H+ from NADP+, with glucose 6-phosphate dehydrogenase (G6PD) as the rate-limiting enzyme.
What is the role of transketolase and transaldolase in the non-oxidative phase?
Transketolase and transaldolase link back to glycolysis by producing glyceraldehyde 3-phosphate and fructose 6-phosphate.
What is the net result of the non-oxidative phase?
The net result is the conversion of three 5-carbon sugars to two 6-carbon sugars and one 3-carbon sugar.
What is the regulatory enzyme of the pentose pathway?
The regulatory enzyme of the pentose pathway is glucose 6-phosphate dehydrogenase (G6PD).
How does NADPH affect G6PD activity?
NADPH is a competitive inhibitor of G6PD; a high NADPH/NADP+ ratio inhibits the enzyme, while a low ratio stimulates it.
What is glutathione composed of?
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine.
What are some functions of reduced glutathione (GSH)?
GSH serves as a reductant, conjugates to drugs, aids in amino acid transport, and acts as a cofactor in enzymatic reactions.
What happens to oxidized glutathione (GSSG)?
GSSG is reduced back to GSH by the enzyme glutathione reductase using NADPH as a cofactor.
What is the consequence of G6PD deficiency?
G6PD deficiency leads to insufficient production of NADPH and glutathione, resulting in increased susceptibility to oxidative stress.
What is favism?
Favism is a condition in which individuals with G6PD deficiency experience hemolysis after eating fava beans.
How does G6PD deficiency affect red blood cells?
In G6PD deficiency, red blood cells cannot regenerate GSH, leading to hemolysis and potential clinical symptoms like black urine.
What percentage of the male African American population is affected by G6PD deficiency?
Approximately 10-14% of the male African American population is affected by G6PD deficiency.
