Pay-off phase reactions — Flashcards

Flashcard 1: Pyruvate kinase deficiency results in increased levels of _____, which causes decreased Hb affinity for O2

Answer: 2,3-BPG

Flashcard 2: Conversion of 1,3-BPG into 3-phosphoglycerate (glycolysis) produces a molecule of _____

Answer: ATP

Flashcard 3: Pyruvate kinase deficiency presents with _____ levels of 2,3-BPG

Answer: increased

Flashcard 4: Which steps (2) of glycolysis require ATP? _____

Answer: 1. Glucose → Glucose-6-phosphate (Hexokinase/Glucokinase) 2. Fructose-6-phosphate → Fructose-1,6-bisphosphate (PFK-1)

Flashcard 5: What substrate overrides inhibition of the enzyme phosphofructokinase-1 by ATP in the liver? _____

Answer: Fructose-2,6-bisphosphate

Flashcard 6: What is the only metabolic pathway for generating ATP, anaerobically? _____

Answer: Glycolysis

Flashcard 7: What is the function of the bifunctional enzyme Phosphofructokinase-2/Fructose bisphosphatase-2 (PFK-2/FBP-2)?

Answer: A bifunctional enzyme that regulates the levels of Fructose-2,6-bisphosphate (F-2,6-BP), thereby balancing glycolysis and gluconeogenesis.

Extra: In the well-fed state, PFK-2 is active (increased F-2,6-BP) → stimulates Glycolysis.\nIn the fasting state, FBP-2 is active (decreased F-2,6-BP) → stimulates Gluconeogenesis.

Flashcard 8: Where does glycolysis take place?

Answer: cytoplasm

Flashcard 9: What is the rate-limiting enzyme of glycolysis?

Answer: Phosphofructokinase-1 (PFK-1)

Extra: The three irreversible steps of glycolysis are catalyzed by:\n1. Hexokinase/Glucokinase\n2. Phosphofructokinase-1 (Rate-limiting step)\n3. Pyruvate kinase\n\nPFK-1 is inhibited by ATP and Citrate, and activated by AMP and Fructose-2,6-bisphosphate.

Flashcard 10: What enzyme converts pyruvate to lactate?

Answer: lactate dehydrogenase (LDH)