Metabolic Pathways

Study Notes

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

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)

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

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

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 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

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

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