(1) All living organisms use the same kinds of building-block molecules.
(2) The identity of each species is preserved by the possession of specific sets of macromolecules (e.g., nucleic acids, proteins, polysaccharides); macromolecules have directionality (head-to-tail orientation) and therefore are informational molecules.
(3) All biomolecules have specific functions.
(4) Cells utilize free energy to do work; energy is provided, either directly or indirectly, by sunlight.
(5) Cells contain enzymes, which are highly specialized protein molecules composed of amino acids. Enzymes are catalysts and often work in sequence. Enzyme activity is regulated. The 3D structure of proteins/enzymes is essential to their activity. N
(6) Cells trap and store energy in a chemical form known as ATP (adenosine 5'-triphosphate). (review energy cycle)
ATP-4 + H2O _ ADP-3 + Pi-2 + H+ + energy
(7) Cell activities are highly regulated.
(8) Living systems can duplicate themselves exactly; undergo mutation (fidelity of base pairing in DNA replication).
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