Metabolism
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Metabolism refers to the set of life-sustaining chemical reactions that occur within living organisms. The three main functions of metabolism are the conversion of energy in food into a usable form fo
Plant cells (bounded by purple walls) filled with chloroplasts (green), which are the site of photosynthesis
Santorio Santorio in his steelyard balance, from Ars de statica medicina, first published 1614
Metabolic waste
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Metabolic wastes or excrements are substances left over from metabolic processes which cannot be used by the organism, and must therefore be excreted. This includes nitrogen compounds, water, CO2, pho
Metabolism
…of food to building blocks of macromolecules (biopolymers) such as proteins, lipids, nucleic acids, and some carbohydrates; and the excretion of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow, reproduce, maintain their structures, and respond to their environments. The word metabolism…
Placental mammals expel urine from the bladder through the urethra during urination.