1. Introductory Chemistry
Chapter 2

2. Chemical Elements Fundamental unit in chemistry
Cannot be broken down by chemical means
112 elements total
Use 1-2 letter symbols for each
e.g. C= carbon, Na = sodium, Cl = chorine.
26 normally present in your body
4 major ones & 8 others significant
(see table 2.1)

3. Atoms Lowest unit of an element Nucleus-protons (+), neutrons (0)
Surrounded by Electrons (-)
Total charge is neutral-
Protons # = electron #
Proton number=atomic number-
defines element

4. Ions, Molecules & Compounds
Atoms interact in characteristic ways
Describing this is chemistry
When two or more atoms are held together with chemical bonds the result is a molecule.
Described by the molecular formula

5. Molecular Formula Example: O2 = oxygen the gas H2O = water
molecule has 2 atoms of oxygen bound together
H2O = water
Molecule has 2 atoms of H (hydrogen) and 1 atom of O (oxygen)
Subscript = # of atoms of element
Connected letters & numbers = molecule

6. Figure 2.3

7. Bonding attraction between atoms to form attachments = molecules
Electrons grouped into shells
preferred number in outer shell leads to chemical activity
Can be covalent, ionic, polar covalent and Hydrogen bonds

8. Ionic Bonds Can donate or accept electrons from another atom ->
Ions = atoms with a charge
Opposite charges attract => bonding
Ionic bonding

9. Figure 2.4
Figure 2.4

10. Covalent Bonds Can share electrons in outer shell -> covalent bonds
e.g. water, many organic compounds
unequal sharing -> polar bond
some partial charges on the molecule

11. Figure 2.5a

12. Figure 2.5b

13. Figure 2.5c

14. Figure 2.5d

15. Figure 2.5e

16. Chemical Reactions- Synthesis
Putting atoms together
A + B => AB
Eg. 2H2 + O2 => 2 H2O
Synthesis in the body = Anabolism

17. Chemical Reactions- Decomposition
Splitting Molecules apart
AB => A + B
Eg. CH4 => C + 2H2
Decomposition in the body = Catabolism

18. Other Reactions Exchange reactions Reversible reactions
both decomposition & synthesis
E. g. AB + CD => AD + BC
Reversible reactions
Go both directions
E. g AB <=> A + B

19. Nature of Water Good solvent for some molecules
Dissolve = Hydrophilic molecules
Don’t dissolve = Hydrophobic molecules
Participates in chemical reactions
Absorbs & releases heat slowly
Needs large amount of heat to evaporate

20. Acid, Base & Salts Acid dissolves => H+ (1 or more)
Base dissolves => OH- ( 1 or more)
Acid plus base react => salt
E.g. HCL + KOH => KCL + H2O
acid base salt

21. pH Concept The concentration of H+ or OH- expressed on the pH scale
0-14
At pH = 7.0: H+conc. = OH- conc.
Less than 7.0 = more H+ (acid)
The smaller the number, the more H+
More than 7.0 = more OH- (alkaline)
The larger the number, the more OH-

22. Organic Compounds
Carbohydrates
Lipids
Proteins
Nucleic acids

23. Carbohydrates Simple sugars = Monosaccharide
Major one in body = glucose
Disaccharides= 2- simple sugars bonded
Formed by dehydration synthesis
E.g. glucose + fructose => sucrose
glucose + galactose => lactose
Glucose + glucose => maltose

24. Figure 2.8

25. Polysacchharides Many sugars bonded in chains
Can have branching structures not usually soluble in water
Glycogen- animal carbohydrate
Polyglucose
Starch- plant carbohydrate
Cellulose- plant polymer
Polyglucose but indigestible = fiber

26. Figure 2.9

27. Lipids Insoluble in water = hydrophobic Triglycerides Phospholipids
Cholesterol
Steroids
Fatty acids
Fat soluble vitamins

28. Figure 2.10

29. Figure 2.11

30. Figure 2.12

31. Cholesterol Ring structures Used to make steroid hormones
Help make membranes stiff
Made in liver

32. Proteins Structural elements in cells Chemical catalysts Hormones
Antibodies
Polymers of amino acids

33. Amino Acid Amino group Carboxyl group Side chain
~20 different side chains
A large variety of structures

34. Figure 2.13

35. Terminology Amino acids joined by peptide bond
2 = dipeptide, 3= tripeptide
Many =polypeptide
Functional polypeptide = protein
Includes structure up to quaternary.
Thus a protein may have 1 or more polypeptide chains

36. Enzymes Proteins serving as chemical catalysts Highly specific
Efficient
May be controlled

37. Figure 2.14

38. Nucleic Acids Polymer of nucleotides => Phosphate
Sugar –pentose (ribose, deoxyribose)
Base- 5 of them (4 per nucleic acid)
Adenine (A), guanine (G), thymine (T), cytidine (C), uracil (U)

39. DNA Deoxyribose & A,T,G,C Bases pair: A-T & G-C
Two polymers hydrogen bonded together
forms a double helix
Stores genetic information on protein sequences.

40. Figure 2.15

41. RNA Ribose & A,U,G,C Single chain Functions in protein synthesis
Required to translate DNA to protein

42. ATP Specialized for energy transport in the cell
Carries energy in the chemical bond between phosphate groups.

43. Figure 2.16