1. Chapter 6
Chemistry of Life

2. Elements - simple substances that make up everything in the world
-can’t be broken down into simpler parts
90 naturally occurring
25 essential for life
-Carbon, Hydrogen, Oxygen, Nitrogen
(96% of human body)
-Trace Elements (table 6.1 pg 142)

4. ATOMS - the building blocks of rock & living things
The smallest particle of an element that has the characteristics of that element.
Structures
-Nucleus- contains protons (+) & neutrons (neutral but have mass)
-Electron Cloud
electrons (-)

5. Electron Energy Levels
Electrons travel around the nucleus in specific regions (levels)
Have a limited capacity for electrons
EL-1 holds 2 electrons
EL-2 holds 8
El-3 holds 8
Electrons in the outer most level = valence e-

6. Atoms Atoms usually contain equal numbers of electron and protons
#p = #e
Atoms usually have no charge He

7. Atomic Number Number of protons -Number of protons
The number found on the top of columns (GROUP NUMBER) = number of valence electrons

8. Isotopes
An atom that has the same # of protons and differs in the number of neutrons.
Carbon-12 (6p+6n)
Carbon-14 (6p+8n)
H-3
He+
Li-7

9. Compounds Composed of 2 or more atoms of different elements H2O CO2
Oxygen
Hydrogen
Hydrogen

10. Covalent Bonds
Bonds- formed by atoms to become more stable. (fill energy levels) (8)
Covalent Bond-Molecules formed when two atoms share electrons
Molecule-a group of atoms held together by covalent bonds

11. Ionic Bonds
ION-Atom that gains or loses electrons (to become more stable)
+ or – charged
Ionic bonds-formed by the attraction between two ions of different charge
Chlorine (-)
(receives)
Sodium (+) (donates)
NaCl

12. Chemical Reactions
Chemical Reactions occur when bonds are formed or broken.
Metabolism-All the chemical reactions in an organism
Chemical Equations are representations of chemical reactions
ReactantsProduct
Number of Molecules 4NaCl (coefficient)
Number of atoms of each element in a molecule
H2O AlCl (subscript)
Conservation of mass-matter is neither created nor destroyed (products = reactants)

13. Chemical Reactions
C O2  CO2
4C+ 4O2  4CO2
Reactants  Product

14. pH Chemical Reactions in organisms depend on pH Scale is 0-14
temperature, energy, amount, pH
pH Scale is 0-14
0 Strong Acid
7 Neutral
14 Strong Base
Acid forms H+ ions in water
Base forms OH- ions in water
Acid
Base

15. Mixtures & Solutions
Mixture – combination of substances that keep their own properties
-you can pick out the different pieces
Solution – one thing is dissolved in another
-cannot pick it out

16. Section 6.2

17. Water *Universal solvent* Most important compound in Living systems
Polar- has a positive end and a negative end
Water molecules are held together by weak Hydrogen Bonds

18. Water
-attracted to ions
And to other polar molecules

19. Water -most things will expand when heated & contract when cooled
WATER is the EXCEPTION!!!
WATER will expand when FROZEN !!!

20. Diffusion
-the movement of molecules from an area of high concentration to an area of low concentration
Diffusion happens b/c of Brownian Motion
- all atoms are in constant motion
Dynamic Equilibrium - movement with no change in concentration

21. High Concentration Low Concentration

22. Section 6.3

23. All living organisms contain CARBON !!!
Carbon can make 4 bonds!!!
Polymer-
a chain of smaller molecules linked together

24. Carbohydrates Carbon:Hydrogen:Oxygen 1:2:1 Store and release ENERGY
Monosaccharides-single sugar
Disaccharide- two sugar
Polysaccharide-many
Starch-complex (plant storage)
Glycogen-stored energy
Cellulose-fiber (gives plants support)
Glucose

25. Lipids-Fats C57H110O6 Long-term energy storage Made of :
Glycerol
Fatty acids
Saturated Fats-Long chains with single carbon bonds
Unsaturated-Chains with double carbon bonds
Fatty Acids
Glycerol
Ex: oils, wax, steroids
Will not dissolve in water

27. Proteins C,H,O,N Make up the structures of tissues, organs & organisms
Amino Acids- small building blocks of proteins
20 amino acids build every protein in the world
Peptide bonds-attach amino acids to form Proteins

28. What proteins do: -building blocks for structure -contracting muscles
-transporting oxygen
-immunity
-regulate other proteins
-chemical rxns

29. Protein Shape is important
Shape is determined by order of aa and their interactions with each other
Shape determines structure
Correct or incorrect structure can mean life or death to a cell
enzymes

30. Enzymes Important proteins found in living organisms
-speed up chemical reactions
-involved in all Metabolic processes
Enzymes have an Active Site
**Lock and Key**

31. Nucleic Acids
A Macromolecule that stores information in the form of a code.
Made up of Nucleotides (C,H,O,N,P)
DNA - the master copy of an organisms information
RNA - makes copies of DNA to build new protein molecules for the organism.