Biology / Unit 3 Bio 0506 short lesson, about 20 seconds
The Second Law of Thermodynamics and Entropy
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The idea
The second law of thermodynamics holds that every energy transfer loses usable energy as heat, raising the universe's entropy, its measure of disorder.
In practice
A cell's metabolic reactions lose energy as heat with every transfer, even as the cell itself stays highly ordered.
Where people slip
A cell stays low-entropy locally only by exporting disorder outward — total entropy still rises.
Your place on the trail
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