Hmp

• What is the primary role of the Pentose Phosphate Pathway?

  Anabolic
• What does the Pentose Phosphate Pathway generate?

  NADPH and pentoses
• What is another name for the Hexose Monophosphate pathway?

  HMP shunt
• How is the HMP shunt related to glycolysis and the TCA cycle?

  It is an alternative pathway for the oxidation of glucose.
• Why is the HMP shunt considered more anabolic in nature?

  Because it is concerned with the biosynthesis of NADPH and pentoses.
• Where are the enzymes of the HMP shunt located?

  In the cytosol
• Which tissues are highly active in the HMP shunt?

  Liver, adipose tissue, adrenal gland, erythrocytes, testes, and lactating mammary gland
• What is the significance of NADPH in tissues involved in lipogenesis?

  NADPH is required for the biosynthesis of fatty acids and steroids.
• What are the two major functions of the Pentose Phosphate Pathway?

  Formation of NADPH and synthesis of ribose
• How does the Pentose Phosphate Pathway contribute to red blood cells?

  It supplies NADPH for the production of reduced glutathione.
• What role does NADPH play in the retina?

  It supplies NADPH for the reduction of retinal into retinol.
• What are the main hexoses absorbed from the gastrointestinal tract?

  Glucose, fructose, and galactose
• How is oxidation achieved in the Pentose Phosphate Pathway?

  By dehydrogenation using NADP+ as the hydrogen acceptor.
• What are the two phases of the Pentose Phosphate Pathway?

  Oxidative phase and non-oxidative phase
• What enzyme converts glucose 6-phosphate to 6-phosphogluconolactone?


  Glucose 6-phosphate dehydrogenase (G6PD)
• What is the product of the reaction catalyzed by 6-phosphogluconate dehydrogenase?

  Ribulose 5-phosphate (Ru5P)
• How many molecules of NADPH are generated for each glucose 6-phosphate in the oxidative phase?

  2 molecules of NADPH
• What is the role of transketolase in the non-oxidative phase?

  It catalyzes the transfer of two carbon units between sugars.
• What is the significance of ribose 5-phosphate (R5P) in nucleotide biosynthesis?

  R5P is an essential precursor for nucleotide biosynthesis.
• What happens if more ribose 5-phosphate is formed than the cell needs?

  It is converted to fructose 6-phosphate (F6P) and glyceraldehyde 3-phosphate (GAP) for glycolysis.
• What is the role of glucose-6-phosphate dehydrogenase in the regulation of the Pentose Phosphate Pathway?

  It is the key enzyme and is stimulated by insulin and NADP+.
• What inhibits glucose-6-phosphate dehydrogenase?

  NADPH and acetyl CoA
• What is the significance of the HMP shunt in generating NADPH?

  NADPH is required for the reductive biosynthesis of fatty acids and steroids.
• How does the Pentose Phosphate Pathway help in red blood cells?

  It provides NADPH for the reduction of oxidized glutathione.
• What is the role of reduced glutathione in red blood cells?

  It removes H2O2, preventing oxidative damage.
• What are the antioxidant enzymes involved in detoxifying superoxide anion and hydrogen peroxide?

  Superoxide dismutase, glutathione peroxidase, and glutathione reductase
• What are the two phases of the Pentose Phosphate Pathway and their functions?

  • Oxidative Phase:
  • Produces NADPH
  • Converts glucose 6-phosphate to ribulose 5-phosphate
  • Non-Oxidative Phase:
  • Interconverts monosaccharides
  • Produces ribose 5-phosphate and other sugars
• What is the significance of NADPH in various tissues?

  • Required for:
  • Biosynthesis of fatty acids and steroids
  • Reduction of oxidized glutathione in red blood cells
  • Synthesis of nucleotides and nucleic acids
• What are the key enzymes involved in the Pentose Phosphate Pathway?

  • Glucose-6-phosphate dehydrogenase (G6PD)
  • 6-phosphogluconate dehydrogenase
  • Transketolase
  • Transaldolase
• What are the main products of the Pentose Phosphate Pathway?

  • NADPH
  • Ribose 5-phosphate
  • Other pentoses and hexoses