Human Metabolism Lecture Notes

Key Concepts

• Metabolism: Process of converting food into energy or storing it for future use.
• Brunch Buffet Analogy: Metabolism is similar to how our body handles different nutrients from a meal.

Nutrient Processing

• Carbs and Fats: Directly oxidized into energy.
• Amino Acids: Converted to molecules that can be broken down like carbs.
• Storage: Excess carbs and fats stored as larger polymers. Amino acids are converted and then stored as fat or glycogen.

Role of Hormones

• Insulin: Helps decide what to burn immediately and what to store.
  • Deficiency or inefficiency leads to metabolic disorders like diabetes.

Metabolic Disorders

• Diabetes: Inability to properly use and store nutritional energy, leading to complications.

Cellular Respiration

• Purpose: Breaks down nutrients to produce ATP (energy).
• Phases:
  • Glycolysis: Glucose breakdown.
  • Kreb's Cycle: Further breakdown into energy.

Nutritional States

• Absorptive State: During or after eating.
  • Excess glucose is stored as fat or glycogen.
• Postabsorptive State: When the body relies on stored energy.

Blood Sugar Regulation

• Insulin: Lowers blood sugar by storing glucose.
• Glucagon: Raises blood sugar by releasing stored glucose.
• Blood Sugar Levels:
  • Too high: Can damage blood vessels.
  • Too low: Body converts fats and amino acids into glucose (gluconeogenesis).

Lipid Transport

• Lipoproteins: Allow fats to move in the bloodstream.
  • LDL: Delivers glucose and fat to fat deposits.
  • HDL: Collects and delivers cholesterol back to the liver.

Metabolic Rates

• Basal Metabolic Rate: Calories needed for basic bodily functions.
  • Influenced by age, sex, body size, and composition.

Key Takeaways

• Energy Conversion: Glucose primarily converted to ATP through cellular respiration.
• Nutrient Storage: Glycogenesis and lipogenesis for excess glucose.
• Insulin's Role: Critical for sugar level regulation and nutrient storage.

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Educational Resources

• Crash Course Biology: Recommended for a more detailed understanding of cellular respiration.

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Acknowledgments

• Contributors: Linnea Boyev, Kathleen Yale, Blake de Pastino, and more.
• Crash Course: Supported by Patreon patrons, filmed in the Doctor Cheryl C. Kinney Studio.