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The nitrogen cycle (article) | Khan Academy
网页Review your understanding of the nitrogen cycle in this free article aligned to AP standards.
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网页How molecules other than glucose enter cellular respiration. Use of cellular respiration intermediates for biosynthesis.
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网页Learn how to use Hess's law to calculate the enthalpy of a chemical reaction from the enthalpies of other reactions. Watch a worked example with step-by-step explanations.
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网页Learn about amino acid metabolism in this Khan Academy video.
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网页The carbon cycle is a process where carbon atoms are recycled through the Earth's ecosystems.
Hydrogen bonds in water (article) | Khan Academy
网页The structure of water molecules and how they can interact to form hydrogen bonds.
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网页Metabolism refers to the set of chemical reactions that occur within living organisms to maintain life. Anabolism is the process of building up larger, more complex molecules from smaller ones. This process requires energy. Catabolism is the process of breaking down larger molecules into smaller ones. This process releases energy that can be used by the …
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