Chapter 2 BIO 117 notes.docx

Chapter 2 BIO 117 notes.docx - Matter consists of elements...

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Matter consists of elements in pure form compounds Elements cannot be broken down compound is 2 or more elements combined Nitrogen, Oxygen, Carbon, Hydrogen=96.3% of living matter Of 92 naturally occurring elements 20-25% are essential to life Trace elements are required in minute quantities Chemical Behavior of atoms is mainly affected by the number of electrons Animals require 25 elements that are obtained organically, plants require 17 elements acquired inorganically Levels of Biological Organization Atoms-Molecules-Organelles-Cells-Tissues-Organs-Organ Systems-Organisms Energy flows through ecosystem, chemicals cycle through Darwin laws- Elements properties depend of structure of atoms Atom is composed of protons, neutrons and electrons Atom- Smallest building block of matter that still retains properties of element Particles Neutron Proton Electron Charge O + - Location Nucleus Nucleus Outside Nucleus Mass 1dal 1dal -1/2000 dal Atomic number is only amount of Protons, atomic mass is protons + neutrons When looking at Atom Notation C 12 <-- Atomic Mass C 6<---Atomic Nu mber Isotopes have same Atomic Number and different Atomic Mass ie. o 12C 13C 14C C-14 is radioactive isotope that has many more neutrons than C-12. Spontaneously decays off energy particles o Likely to occur when atom has too many neutrons Radioactive Tracers exist to track atoms through metabolism also used for dating Radiometric Dating
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