1. Chapter 2
Chemical Principles

2. Definitions and Concepts to review
Atom, molecule, ion, electron, proton, neutron, element, compound, valence e-, e- shells
3 types of bonds: ionic, covalent, hydrogen
Chemical reactions

3. Important biological molecules
Water
Polar, cohesive, adhesive
Solvent
Absorption of heat

4. pH = measure of hydrogen ion (H+) concentration
Acids, bases,
neutral compounds
Add H+ lowers pH number
Add OH- raises pH number
Neutral = pH 7
Most microbes grow best at neutral pH
Buffers are chemicals which maintain a certain pH

5. What are organic molecules?
Molecules of organisms/life
Carbon-based
Always contain carbon and hydrogen
May contain other elements, such as sulfur, phosphorus, nitrogen, oxygen, etc.

6. 4 types of organic molecules
Carbohydrates
Lipids
Proteins
Nucleic acids

7. Carbohydrates Name means carbon + water
Chemical formula is 1 carbon + 2 hydrogens + 1 oxygen
Examples of carbohydrates:
Sugars, starches, cellulose, chitin
The most important carbohydrate is glucose (C6H12O6)
Functions of carbohydrates
Energy
Energy storage
Structures

8. Carbohydrates
Glucose
C6H12O6
Ref.:

9. Carbohydrates

10. Carbohydrates
Carbo-
-saccharide
Gluco-
Glyco-

11. Lipids
Hydrophobic
Examples: fats, oils, waxes, phospholipids, mycolic acid, most hormones, cholesterol
Function: energy storage, structures, communication, protection from dehydration

12. Lipids
Basic structure of a lipid is 1 glycerol (3C) + 3 fatty acid chains

13. Phospholipids

14. Cholesterol and Ergosterol
Ref. :

15. Lipids
Lipo-
-lipid

16. Proteins SHAPE = FUNCTION Made of amino acids
Examples: insulin (a hormone), hemoglobin, enzymes (-ase suffix)
Functions: carry out chemical reactions, structures, hormones
Denaturation is unfolding of protein

17. Proteins

18. Proteins H
NH2 C
COOH
R side group

23. Proteins
Prot-
Proteo-
Peptid-

24. Nucleic acids
Chemical formula is 1 5 carbon sugar, 1 base (containing nitrogen), and 1 phosphate group
Subunits are called nucleotides
Examples: DNA, RNA, ATP
Functions: carrying genetic information, energy molecules

25. Nucleic acids

26. Nucleic acids Differences between DNA and RNA
DNA has one less oxygen in its sugar, ribose, than RNA
DNA has the 4 bases: A, T, G, C; RNA has the 4 bases: A, U, G, C
DNA is usually double-stranded; RNA is usually single-stranded

28. ATP Energy currency of the cell
Energy is contained in the bonds that hold the phosphate groups to the rest of the molecule
ATP becomes ADP (adenosine diphosphate) when it loses 1 phosphate group

29. Adenosine triphosphate (ATP)

30. Nucleic acids
Nucl-
Nucleo

31. The End