COLLEGE PHYSICSChapter # Chapter TitlePowerPoint Image SlideshowANATOMY & PHYSIOLOGYChapter 2 THE CHEMICAL LEVEL OF ORGANIZATIONFigure 2.1:Human DNAHuman DNA is described as a double helix that resembles a molecular spiralstaircase. In humans the DNA is organized into 46 chromosomes.
WHAT ARE WE DOING?2.1Elements and Atoms2.2 Chemical Bonds2.3 Chemical Reactions2.4 Inorganic Compounds Essential to Human Functioning2.5 Organic Compounds Essential to Human Functioning
PART 1 – BASIC CHEMISTRYMatterMatteris anything that has mass and occupies space•Matter can be seen, smelled, and/or felt•Exists in 3 basic states•Solid: definite shape and volume•Liquid: changeable shape; definite volume•Gas: changeable shape and volume
ENERGYEnergy:the capacity to do work or put matter into motion•Energy does not have mass, nor does it take up space•The greater the work done, the more energy it uses upEnergy exists in two possible forms•Kinetic– energy in action•Potential– stored (inactive) energy
ENERGY (CONT.)Forms of energy•Chemical energy•Stored in bonds of chemical substances•Electrical energy•Results from movement of charged particles•Mechanical energy•Directly involved in moving matter•Radiant or electromagnetic energy•Travels in waves (example:heat, visible light, ultraviolet light, and Xrays)Energy may be converted from one form to another•Example: turning on a lamp converts electrical energy to light energy
2.2ATOMS AND ELEMENTSAll matter is composed ofelements•Elements are substances that cannot be broken down into simplersubstances by ordinary chemical methodsThe Periodic Table of the Elements Figure 2.4(credit: R.A. Dragoset, A. Musgrove, C.W. Clark, W.C. Martin)
Figure 2.2: Elements of the Human BodyThe main elements that compose the human body are shown from mostabundant to least abundant.•Four elements make up 96.2% of body: Carbon, oxygen, hydrogen, and nitrogen•Seven more elements make up 3.7% of body•Trace elements make up <0.1% of body7
STRUCTURE OF ATOMSAtoms are composed of three subatomic particles:•Protons•Carry a positive charge (+)•Weigh an arbitrary 1atomicmassunit(1 amu)•Neutrons•Have no electrical charge (0)•Also weigh 1 amu•Electrons•Carry a negative charge ()•Are so tiny they have virtually no weight (0 amu)•Atoms are electrically neutral when the numbers of protons andneutrons are equal•Protons and neutrons are found in a centrally locatednucleus;electrons orbit around the nucleus in electron shells.
FIGURE 2.3Two Models of Atomic Structure(a)In the planetary model, the electronsof helium are shown in fixed orbits,depicted as rings, at a precisedistance from the nucleus, somewhatlike planets orbiting the sun.(b)In the electron cloud model, theelectrons of carbon are shown in thevariety of locations they would haveat different distances from thenucleus over time.