BSC 109 1st Edition Lecture 2 Outline of Last Lecture I. The characteristics of lifeII. Living things are grouped according to characteristicsIII. Defining features of humansIV. Biological organizationV. Science as knowledge and a processVI. The Cholera outbreakOutline of Current Lecture I. All matter consists of elements II. Atoms are the smallest functional unit that retains the properties of an elementIII. ElementsIV. Chemical bonds link atoms to form moleculesV. Energy fuels life’s activitiesCurrent LectureI. All matter consists of elementsA. Matter1. Anything that has mass and occupies space2. Composed of elementsB. Elements1. Cannot be broken down into a simpler form2. Periodic table lists all known elements (only need to know a few of them)II. Atoms- the smallest functional unit that retains the properties of an elementA. Proton1. Positive charge2. Determines elementB. Neutron1. No charge2. Determines isotopeC. Electron1. Negative chargeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. Participates in chemical reactions3. Outer shell electrons determine chemical behaviorD. Nucleus consists of neutrons and protonsE. Each element consists of one type of atomIII. ElementsA. Of the 92 elements, 25 are essential to life1. Carbon2. Hydrogen3. Oxygen4. Nitrogen B. Trace elements occur in small amountsC. Compound: substance consisting of two or more elements in a fixed ratio1. Iodine in salt prevents goiter2. Fluoride in water prevents cavitiesIV. Chemical bonds link atoms to form moleculesA. Chemical bonds: attractive forces holding atoms togetherB. Covalent bonds1. Form when atoms share electrons (equally or unequally)2. Results in each atom having a maximally filled outermost shell of electrons3. It is the strongest of the chemical bonds4. Example: the bonds between hydrogen and oxygen in a molecule of waterC. Sharing electrons1. Nonpolar covalent bonds: electrons are shared equally (H2, O2, CH4)2. Polar covalent bonds: electrons are NOT shared equally (H2O)D. Ionic Bonds1. Moderately strong bond2. Ion: an electrically charged atom or molecule3. Positively charged ion: forms if an atom or molecule gains electrons4. Negatively charged ion: forms if an atom or molecule gains electrons5. Ionic bond: attractive force between oppositely charged ions 6. Example: the bond between Na+ and Cl- in saltE. Hydrogen Bonds1. Weakest of the bonds2. The bond between oppositely charged regions of molecules that contain covalently bonded hydrogen atoms3. They are very common4. Example: the bonds between molecules in waterV. Energy fuels life’s activitiesA. Energy: the capacity to do workB. Potential energy: stored energyC. Kinetic energy: energy in motion, doing workD. Potential energy can be transformed into kinetic
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