Metabolic Pathways

Metabolic Pathways

Definition

• A series of chemical reactions that occur within a cell to convert a molecule into another molecule
• Involves the transformation of energy and nutrients into the components that make up living organisms

Types of Metabolic Pathways

• Catabolic Pathways: Break down complex molecules into simpler molecules, releasing energy (e.g., glycolysis, citric acid cycle)
• Anabolic Pathways: Build complex molecules from simpler molecules, requiring energy (e.g., gluconeogenesis, protein synthesis)

Key Metabolic Pathways

• Glycolysis:
  • Breaks down glucose into pyruvate
  • Produces ATP and NADH
  • Occurs in cytosol
• Citric Acid Cycle (Krebs Cycle or Tricarboxylic Acid Cycle):
  • Breaks down acetyl-CoA into carbon dioxide
  • Produces ATP, NADH, and FADH2
  • Occurs in mitochondrial matrix
• Pentose Phosphate Pathway:
  • Generates NADPH and pentoses (5-carbon sugars)
  • Important for nucleic acid synthesis and redox reactions
  • Occurs in cytosol
• Fatty Acid Oxidation (β-Oxidation):
  • Breaks down fatty acids into acetyl-CoA
  • Produces ATP and NADH
  • Occurs in mitochondrial matrix
• Gluconeogenesis:
  • Synthesizes glucose from non-carbohydrate sources (e.g., amino acids, lactate)
  • Occurs in liver and kidney cells
• Protein Synthesis:
  • Builds polypeptide chains from amino acids
  • Occurs in ribosomes

Regulation of Metabolic Pathways

• Feedback Inhibition: End products of pathways inhibit earlier steps to prevent excessive production
• Allosteric Regulation: Enzymes are activated or inhibited by binding of molecules to specific sites
• Hormonal Regulation: Hormones (e.g., insulin, glucagon) stimulate or inhibit metabolic pathways

Importance of Metabolic Pathways

• Energy Production: Generate ATP for cellular activities
• Biosynthesis: Provide building blocks for the synthesis of macromolecules (e.g., carbohydrates, proteins, lipids)
• Homeostasis: Maintain cellular balance and regulate metabolic processes

Metabolic Pathways

Definition

• Metabolic pathways are series of chemical reactions within a cell that convert one molecule into another
• These reactions transform energy and nutrients into components of living organisms

Types of Metabolic Pathways

• Catabolic Pathways: Break down complex molecules, releasing energy
• Anabolic Pathways: Build complex molecules, requiring energy

Key Metabolic Pathways

Glycolysis

• Breaks down glucose into pyruvate
• Produces 2 ATP and 2 NADH
• Occurs in cytosol

Citric Acid Cycle (Krebs Cycle or Tricarboxylic Acid Cycle)

• Breaks down acetyl-CoA into carbon dioxide
• Produces 2 ATP, 6 NADH, and 2 FADH2
• Occurs in mitochondrial matrix

Pentose Phosphate Pathway

• Generates NADPH and pentoses (5-carbon sugars)
• Important for nucleic acid synthesis and redox reactions
• Occurs in cytosol

Fatty Acid Oxidation (β-Oxidation)

• Breaks down fatty acids into acetyl-CoA
• Produces ATP and NADH
• Occurs in mitochondrial matrix

Gluconeogenesis

• Synthesizes glucose from non-carbohydrate sources (e.g., amino acids, lactate)
• Occurs in liver and kidney cells

Protein Synthesis

• Builds polypeptide chains from amino acids
• Occurs in ribosomes

Regulation of Metabolic Pathways

• Feedback Inhibition: End products inhibit earlier steps to prevent excessive production
• Allosteric Regulation: Enzymes are activated or inhibited by binding of molecules to specific sites
• Hormonal Regulation: Hormones (e.g., insulin, glucagon) stimulate or inhibit metabolic pathways

Importance of Metabolic Pathways

• Energy Production: Generate ATP for cellular activities
• Biosynthesis: Provide building blocks for macromolecule synthesis (e.g., carbohydrates, proteins, lipids)
• Homeostasis: Maintain cellular balance and regulate metabolic processes

Learn about the series of chemical reactions that occur within a cell to convert a molecule into another molecule, including catabolic and anabolic pathways.