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The Chemical Basis of Life: Summary

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From hippocampus.org (Approved: helpingnorth), produced by University of California
 
This is a video slide show accompanied by text:"Living organisms use only a small fraction of the known chemical elements to carry out all of their biological functions. Six elements make up more than 99% of matter in living systems: hydrogen, carbon, nitrogen, oxygen, phosphorous, and calcium. Five elements are found in much smaller amounts: sodium, magnesium, sulfur, chlorine, and potassium. Finally, 14 elements are known as "trace" elements because living organisms require them in minute quantities.
An atom is the fundamental unit of chemical matter. An atom consists of a nucleus, containing positively charged protons and uncharged neutrons, surrounded by a cloud of negatively charged electrons. Atoms of the same element that differ in the number of neutrons are called isotopes..."
 
Ages: 12 - 18 License: Proprietary Owner: unspecified Found by helpingnorth
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