Unit 3 · 3.3 — Cellular Energy [cite: 9, 10, 28]

Everything to learn here

• Concept: Life requires a highly regulated, continuous input of energy to maintain structural order and offset the universe's tendency toward entropy, according to the laws of thermodynamics [cite: 10, 13].
• Concept: The highly conserved metabolic processes of glycolysis and oxidative phosphorylation provide powerful molecular evidence of common ancestry across all domains of life [cite: 28].
• Equation: Equation/Process: Gibbs Free Energy: $\Delta G = \Delta H - T\Delta S$. Exergonic reactions (negative $\Delta G$) spontaneously release energy; endergonic reactions (positive $\Delta G$) require an input of energy [cite: 13, 14, 31].
• Vocabulary: Reaction Coupling — the energetic linking of a highly exergonic process (like ATP hydrolysis) to drive a necessary endergonic process [cite: 13].
• Concept: Living systems require constant energy input to maintain order and power cellular processes.
• Concept: Life maintains order by coupling energy-releasing processes with energy-consuming ones to satisfy thermodynamic laws.
• Concept: Biological pathways are sequential, using the product of one reaction as the substrate for the next.

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