Metabolism and Nutrition Lecture

Introduction

• Misuse of the term "metabolism"
  • Commonly associated with weight gain/loss
  • True definition: Sum of all chemical reactions in an organism
• Metabolism = Catabolism + Anabolism

Key Concepts

Catabolism

• Breakdown of organic molecules
  • Releases energy
  • Example: Breakdown of sugars, lipids, proteins

Anabolism

• Synthesis of new organic molecules
  • Requires energy
  • Uses: Structural maintenance, growth, secretions, nutrient reserves

Nutrients

• Carbohydrates: Sugars, quick energy source

  • Structure: Carbohydrates (carbon surrounded by water)
  • Types: Monosaccharides (glucose), Disaccharides (maltose), Polysaccharides (starch, glycogen, chitin)

• Lipids: Fats, energy storage, insulation, hormone synthesis

  • Structure: Triglycerides (glycerol + 3 fatty acids)
  • Types: Saturated vs. Unsaturated fats

• Proteins: Most abundant organic compound

  • Amino acids: Building blocks
  • Functions: Support, movement, transport, buffering, enzymes, hormones, defense

• Nucleic Acids: DNA/RNA

  • Obtained from diet, broken down to synthesize new nucleic acids

• Vitamins and Minerals

  • Vitamins: Organic compounds, essential in small amounts
  • Minerals: Inorganic ions, critical for various biological functions

Energy Processes

Aerobic Respiration

• Glycolysis: Breakdown of glucose into pyruvate; in cytoplasm

  • Produces: 2 ATP, 2 NADH

• Kreb Cycle: Uses pyruvate to produce electron carriers in the mitochondrial matrix

  • Produces: 2 ATP, NADH, FADH2, CO2

• Oxidative Phosphorylation: Uses oxygen to produce ATP in mitochondria

  • Produces: Approximately 30 ATP

Anaerobic Respiration

• Occurs when oxygen is insufficient
• Produces lactic acid in muscles
• Only yields ATP from glycolysis (net gain: 2 ATP)

Metabolic Pathways

Lipid Metabolism

• Lipolysis: Breakdown of lipids for energy
  • Glycerol to pyruvate, fatty acids to acetyl CoA
  • Beta-oxidation: Breakdown into acetyl CoA, producing large amounts of ATP

Protein Metabolism

• Proteins broken down via hydrolysis
• Amino acids can be used for gluconeogenesis or directly enter the citric acid cycle

Nutritional Aspects

Balanced Diet

• Emphasis on grains, vegetables, fruits, dairy, and proteins
• Importance of dietary fiber for digestive health

Reading Nutrition Labels

• Serving sizes, calories, and daily values
• Monitoring intake of fats, cholesterol, sodium, and carbohydrates

Conclusion

• Understanding metabolism and proper nutrition is critical for maintaining health and energy levels.
• Regular assessment of diet can prevent various health issues.