Metabolism and Energy in the Body - Revision Sheet

1. 📌 Essentials

• ATP is the main energy currency in cells, composed of adenine, ribose, and three phosphate groups. Cellular metabolism is divided intoabolism (energy release) and anabolism (energy consumption).
• Photosynthesis converts light energy into chemical energy in autotrophs; respiration releases energy from glucose.
• Autotrophs produce organic molecules from inorganic substances; heterotrophs consume organic matter.
• Digestion breaks down macromolecules into absorbable monomers.
• Energy flow in ecosystems moves from autotrophs to heterotrophs via food chains.
• Hydrolysis of ATP releases energy necessary for cellular processes.
• Fermentation is an anaerobic pathway producing small amounts of ATP.
• Vitamins act as cofactors for enzymatic reactions in metabolism.
• Nutrients are classified into energetic (carbohydrates, lipids, proteins) and non-energetic (vitamins, minerals, water).