What structural
tructural difference explains why lipids provide more energy to a cell than an equal mass
of proteins or carbohydrates?
Lannroteins or carbohydrates.
Lipids have more hydrogen atoms bonded to carbon than carbohydrates and proteins.
−
C
H
2
−
is a typical carbon hydrogen bond in lipids. When oxidized, this carbon releases 6 electrons that it can donate to reduce NAD and FAD during the electron transport chain of cellular respiration.
H
−
C
−
O
H is a typical C-H bond in carbohydrates. When oxidized, this bond only releases 4 electrons.
Moreover, a higher concentration of proton is generated by breakage of the CH bond in lipids. This would generate a steeper proton gradient required for running the enzyme ATP synthase. As more protons cross the mitochondrial membrane, the ATP synthase phosphorylates more ADP molecules resulting in a greater production of ATP.
