Biology notes

Biology notes - Biology 1201 notes 8-28-07 What is Science?...

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Biology 1201 notes 8-28-07 What is Science? Body of knowledge System of explaining Scientific Method Observation--generalization or model--hypothesis--test--new observations Circular process- starts with observation and end with observations but new ones Trying to get closer to the truth and reality. The more you go around the process the closer you get Graph: Terms: Hypothesis- explanation that is untested- little or no support Theory-explanation tested multiple times and is always supported Law-theory that has been continuously tested and supported What is biology? The study of life What is life? Cannot be defines by a single characteristic Respond to stimuli Reproduce/grow Exist by themselves Have organization Energy use Interact Change/evolve Development 8-30-07 Scale of nature What scales are biologists interested in? Atom (10 -8 meters) to the community/ecosystem (10 +6 meters) HUGE RANGE! Approaches to biology Reductionism approach- take structure apart and study them Whole- properties only emerge when it’s whole Start with reductionism and build up to whole Why is atomic structure biologically important? Organisms are composed largely of 11 basic elements Value of an average human chemically $930 Solubility Like substances dissolve like substances Like = polarity Polar solutes dissolve in polar solvents and vice versa Atom Smallest unit of matter separated by normal chemical means Smallest unit of matter that retains all of the properties of that element Subatomic particles Protons-----1 Dalton (mass) -----+1 Neutrons---1 Daltons-------------0 Electrons-- ~0 Daltons----------- -1 Atomic # = # of protons on an atom Atomic mass = # of protons and neutrons in an atom Bohr model
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K inner shell- holds 2 electrons L holds 8 electrons M holds 8 electrons Nucleus holds protons and neutrons Valence The number if electrons needed to be gained or lost to fill the outer shell Also predicts number of bonds an atom will form Ex. Hydrogen- valence of 1 Helium- valence of 0 (noble gas) Carbon- valence of 4 Chemical bonds Form when atoms gain and lose or share electrons The result of electrical attractions between atoms Strong bonds- ionic and covalent Ionic bond Forms when atoms completely gain and lose electrons Strongest bond when it’s under dry conditions Na+1 opposites attract Cl -1 Covalent bonds Forms when atoms share electrons If equally shared- just a covalent bond If unequal then it’s a polar covalent bond Becomes the strongest bond in water Holds most of our bonds together Are covalent, polar covalent and ionic bonds really different? Ionic bonds-----lead to-----polar covalent----which leads to------covalent Different ends of the same gradation What determines the # and type of chemical bond? The # of bonds is determined by the valence of that atom
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Biology notes - Biology 1201 notes 8-28-07 What is Science?...

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