Lecture Notes: How Energy Fuels the Body

Key Terms and Concepts

• Ingestion: Eating/consuming food
• Digestion: Breaking down food; starts in the mouth, continues in the stomach and small intestine
• Metabolism: Chemical processes to maintain life
  • Anabolism: Uses energy to produce new molecules
  • Catabolism: Breaks down molecules to generate energy
• Absorption: Nutrients entering the bloodstream
• Transportation: Moving nutrients to where they are needed in the body

Digestive and Metabolic Processes

• Ingestion > Digestion > Absorption > Transportation > Metabolism
• Metabolic pathways are always active, adapting to stimuli

Metabolism Details

• Anabolism: Produces new molecules (requires energy)
• Catabolism: Breaks down molecules (generates energy)

First Law of Thermodynamics

• Energy cannot be created or destroyed; applies to how the body uses chemical energy from food

Functions Fueled by Chemical Energy

• Breathing
• Blood circulation
• Body temperature regulation
• Oxygen delivery
• Waste removal
• Synthesis and repair of tissues

Macronutrients

• Main nutrients: fats, carbohydrates, proteins
• Chemical energy in these nutrients fuels our body

Catabolic Reactions and ATP

• Catabolic reactions produce ATP (adenosine triphosphate)
• ATP is a byproduct of these reactions and generates heat

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