Carbohydrate Metabolism Flashcards

Flashcards on Carbohydrate Metabolism

Glycolysis

Major pathway for metabolism of Glucose, Fructose and Galactose, can occur with or without oxygen.

Anaerobic Glycolysis

Occurs in the absence of Oxygen, produces 2 Lactic Acids and a net of 2 ATP.

Aerobic Glycolysis

Occurs in the presence of Oxygen, produces 2 Pyruvate and a net of 6 ATP.

Substrate Level Phosphorylation

Production of ATP via Glycolysis that involves phosphorylation reactions outside the mitochondria.

Oxidative Phosphorylation

Production of ATP via Glycolysis that involves phosphorylation reactions within mitochondria.

Hexokinase

Converts Glucose to G-6-P, requires ATP, and the reaction is not reversible.

Phosphofructokinase-1 (PFK)

Converts F-6-P to F-1,6-BP, requires ATP, reaction is not reversible, and is the rate-limiting step in Glycolysis.

Aldolase

Splits F-1,6-BP into Dihydroxyacetone Phosphate (DHAP) and Glyceraldehyde-3-Phosphate (Gly-3-P); reaction is reversible.

Triose phosphate Isomerase

Converts DHAP to Gly-3-P, reaction is not reversible.

Glyceraldehyde 3-P Dehydrogenase

Converts Gly-3-P to 1,3-BPG, 2 NAD is converted to 2 NADH + 2 H+, and the reaction is reversible.

Phosphoglycerate Kinase

Converts 1,3-BPG to 3-PG, 2 ADP is converted to 2 ATP via Substrate Level Phosphorylation, and the reaction is reversible.

Enolase

Converts 2-PG to PEP, reaction is reversible.

Pyruvate Kinase

Converts PEP to Pyruvate, 2 ADP is converted to 2 ATP via Substrate Level Phosphorylation, and the reaction is not reversible.

Lactate Dehydrogenase (LDH)

Enzyme that converts Pyruvate to Lactate under anaerobic conditions, regenerating NAD+.

Pyruvate Dehydrogenase (PDH) Complex

Converts Pyruvate to Acetyl-CoA under aerobic conditions in the mitochondria, linking Glycolysis to the TCA cycle.

2,3-BisPhosphoglycerate (2,3-BPG) Shunt

Glycolysis in RBCs, mainly to form 2,3-BPG.

Bis-Phosphoglycerate Mutase

Enzyme in RBCs that converts 1,3-BPG to 2,3-BPG.

2,3-BPG Phosphatase

Enzyme in RBCs that converts 2,3-BPG to 3-PG.

TCA Cycle

Series of enzymatic reactions for catabolism of Acetyl-CoA, occurring within the Mitochondrial matrix under Aerobic conditions.

Gluconeogenesis

Synthesis of Glucose from non-carbohydrates sources, occurs mainly in the liver and lesser extent in the kidneys.

Cori Cycle (Lactic acid cycle)

Anaerobic Glycolysis in muscle produces lactate, released in blood and transported to liver for Gluconeogenesis to convert lactate to glucose, which is released back in the blood.

Alanine Cycle

Breakdown of protein in muscle gives amino acids, these can transaminate with Pyruvate to form Alanine, which transported to the liver, and converted to glucose via Gluconeogenesis.

Pentose Phosphate Pathway (HMP Shunt)

Alternative pathway for glucose metabolism, does not generate ATP, but produces NADPH for Fatty acid & Cholesterol synthesis, and Ribose-5-phosphate for Nucleotide and Nucleic acid synthesis.

Glycogenesis

Glycogen synthesis, occurs mainly in liver, but muscle contains more glycogen.

Glycogenolysis

Glycogen degradation, involves Glycogen Phosphorylase and Glycogen-Debranching enzymes.