Metabolism and Glycolysis Concepts

The chemical reactions that occur in the body to break down and build up substances.

Metabolic pathways that build complex molecules from simpler ones, requiring energy.

Metabolic pathways that break down complex molecules into simpler ones, releasing energy.

Metabolic pathways that act as links between anabolic and catabolic pathways.

The processes involved in the body's use and breakdown of carbohydrates.

Process of breaking down complex carbohydrates (polysaccharides and disaccharides) into simple sugars (monosaccharides) for absorption.

A condition where the body has difficulty digesting lactose, a sugar found in milk and dairy products, due to a lactase deficiency.

Simple sugar molecules that are the end products of carbohydrate digestion, easily absorbed.

Symptoms like abdominal distension, cramps, and diarrhea, caused by undigested lactose fermenting in the gut.

Lack of the enzyme lactase leads to undigested lactose, which intestinal bacteria then ferment into acids and gases.

The breakdown of glucose into pyruvate under oxygen or into lactate without oxygen, a major glucose pathway.

Occurs in the cytoplasm of all cells, crucial in cells without mitochondria (e.g., red blood cells) or with fluctuating oxygen supply (e.g., muscles during exercise).

Two stages: (1) energy-requiring, converting glucose into glyceraldehyde-3-P; (2) energy-producing, converting glyceraldehyde-3-P to pyruvate/lactate.

Aerobic glycolysis produces 6-8 ATP molecules.

Anaerobic glycolysis produces 2 ATP molecules.

Glycolysis also processes fructose and galactose from the diet.

2,3-BPG, a byproduct of glycolysis, decreases hemoglobin's oxygen affinity, promoting oxygen release to tissues.

Glycolysis generates intermediates used in other metabolic pathways, like glycerol-3-phosphate for lipid synthesis and pyruvate for amino acid synthesis.

Glycolysis initially consumes 2 ATP molecules before generating ATP.

Direct transfer of phosphate group from a substrate to ADP to form ATP, without the need of the electron transport chain.

ATP production using energy from the electron transport chain in the mitochondria.

8-10 ATP generated, gained from both substrate-level and oxidative phosphorylation in the complete breakdown of glucose in the presence of oxygen.

2 ATP generated from substrate-level phosphorylation only when glucose breakdown occurs without oxygen.

Lactate is the final product of glycolysis in red blood cells (RBCs).

Glucose uptake in red blood cells (RBCs) is independent of insulin.

Red blood cells produce 2,3-BPG, which regulates hemoglobin oxygen affinity.

Hexokinase/Glucokinase, Phosphofructokinase-1 (PFK-1), and Pyruvate Kinase are the three irreversible enzymes crucial to glycolysis.

Insulin stimulates the synthesis of key glycolytic enzymes; glucagon inhibits their synthesis.

Allosteric regulators such as G-6-F, Fructose 2,6-bisphosphate, citrate, and fructose 1,6-bisphosphate influence the activity of glycolytic enzymes.

Pyruvate kinase is inactivated by phosphorylation.

ATP inhibits PFK-1 and pyruvate kinase; ADP and AMP stimulate PFK-1.

Stimulates glycolysis and inhibits gluconeogenesis.