BIOB34H3 Lecture Notes - Lecture 5: Energy Density, Chemotroph, Hydrophile
Document Summary
Main way to store energy is fat (most preferred way) because: 2 reasons. Fat as an energy source has a higher calorific value[3] (higher energy density = more energy per gram) this is because lipids have more electrons packed onto them compared to carbs and proteins. Animals harvest energy by stripping electrons from the organic material they ingest and using o2 as an electron acceptor (more electrons to strip, more energy). Fats are hydrophobic, unlike carbs and proteins that are hydrophilic. Carbs and proteins attract water which weighs them down and reduces their energy density compared to fats. We can also use biomolecules as a source of energy. Ex: being in a car accident and bedridden for months causes muscle atrophy because the body uses the inactive muscle proteins as a source of energy from an economic standpoint. All energy is free energy to perform biosynthesis and work, except for heat.
