BIO152H5 Chapter Notes - Chapter 2: Chemical Polarity, Radionuclide, Unified Atomic Mass Unit
Document Summary
Chapter 2: chemistry of life. Tuesday, december 9, 2014. Matter : made up of elements (cannot be divided into other substances) Essential elements: 20- 25% of the 92 elements are essential to living things. >> oxygen, carbon, hydrogen, nitrogen. >> humans need 25 , plants need 17. Trace elements: required by organism in only minute quantities (ex. Serpentine plant communities: plants that grow in toxic soil ( soil with chromium, nickel, & cobalt). Dalton: amu (atomic mass unit) Atom >> protons, neutrons and electrons. >> protons + neutrons = mass # >> protons/ electrons = atomic # Isotope: different atomic form of the same element (more/less neutrons) Radioactive isotope: an isotope with a nucleus that decays spontaneously, giving off particles & energy. Pet scanners: monitor chemical reactions as they occur in the body. Radioactive isotopes can be dangerous b/c it can damage cellular molecules. Radioactive isotopes help determine the actual age of fossils (radiometric dating) Energy: capacity to cause change.
