Bioenergetics
Bioenergetics
=energy associated with biological systems. Release, storage, and use of this energy.75% of diet DM used for energy. Energy is not a nutrient, derived from organic compounds (protein, CHO, fat) in the diet
Energy derived
= complete or partial oxidation of organic compounds. These organic compounds absorbed in the GI tract. Energy is in chemical form (stored in bonds - covalent bonds). If animals can break these bonds - they can use this energy released from the breaking of these bonds. Energy may escape!Trapping energy
= Requires systematic breaking of bonds & trapping electrons. Electrons are actually where energy comes from.e-
® O2 ® H2O and results in energy available for workSystemic breaking of bonds
= required to produce energy - examples: glycolosis, Krebs.Chemical energy originally from the sun!!
CO2 + H2O + ATP
® glucose (protein, fats, CHO's) All are forms of chemical energy.So reverse the action to release energy.
Heat
= most common form of energy in biochemical reactions because most chemical energy will be converted to heat (INEFFICIENT!!!)Inefficient metabolism
= Body is not 100% efficient, not all ATP energy will be used for work. Heat will escape (given off) = allows for optimum body temperature maintenanceCalorie
= the unit of heat measured.Definition = the amount of heat required to raise the temperature of 1g of H2O 1oC from 14.5 oC to 15.5 oC at 1 atmospheric pressure.
Kilocalorie = 1000 calories
Gross Energy
(or caloric density) = Total energy in a compound. Measure with bomb calorimeterBomb calorimeter
= Pure O2 environment, combust (ignite) = blows up. All chemical energy is converted to heat - measure heat produced and that is caloric density or Gross Energy!Glucose = 3.75 kcal/g
CHO = 4 kcal/g
Protein = 4 kcal/g
Fat = 9 kcal/g
Alcohol = 7 kcal/g
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