1. Chapter 2
The Chemistry of Life

2. 2.1 The nature of matter
Atom: the smallest particle of an element that has the properties of that element
Atom is made of three subatomic particles:
Proton * Positive, nucleus
Electron * Negative, outside nucleus in energy levels
First energy level -- 2e
Second energy level -- 8e
Third energy level -- 18e
Neutron * No charge, nucleus

5. Number of protons usually is equal to the number of electrons so that the overall charge of an atom is neutral!! 
If atoms of the same element have different number of neutrons, they are called isotopes! EX. C - 12 , C - 13, C - 14
When two or more atoms of different elements are chemically combined you create what is called a compound. EX. Water

6. Compounds can be made with three different kinds of bonds:
Covalent
Share electrons to be stable
Strongest and most common bond
Molecule: group of atoms held together with covalent bonds with no overall charge
Van der Waals forces (what holds molecules together)

7. Ionic Hydrogen Gain / lose electrons to be stable
Ion: a charged particle
Less abundant in living things than covalent bonds
Hydrogen

8. Mixtures & Solutions
Mixture: a combination of substances in which the individual components retain their own properties
 Solution: a mixture in which one or more substances are distributed evenly in another substance
Two parts to every solution:
Solute --- What is being dissolved
Solvent -- What is doing the dissolving * Most common... WATER

9. pH pH: a measure of how acidic or basic a solution is
Acid: substance that forms H+ ions in water
0 - 7
Base: substance that forms OH- ions in water
7 – 14

11. Acids & Bases Acids Bases Higher concentration of H+ ions
pH value less than 7
Sour taste
React with metals
Blue litmus paper will turn red if an object is an acid
Lower concentration of H+ ions
pH value more than 7
Bitter taste
Slippery
Turn red litmus paper blue if an object is a base

12. 2.2 Water and Diffusion
Perhaps the most important compound in living organisms is water!
Properties of water:
Polarity
Has a positive and negative end
Gives water its dissolving property
Resists Temperature Changes
Water expands when it freezes
Adhesion  Graduated cylinder
Adhesion is greater between glass & water than water & water!

13. 2.3 Carbon Compounds
The one element that defines living organisms is Carbon!
Carbon has four electrons in its outermost shell; therefore, it can combine with almost every other element
Any compound that contains carbon is considered to be an organic compound!
If it does not contain carbon it is inorganic.

14. Four types of Organic compounds:
Carbohydrates:
Made of C, H, O (C to H ration is 2 to 1)
Monomer: monosaccharide
Function: Provide quick energy
EX. Glucose: how animals store food
Starch: how plants store food
Cellulose: composes cell walls of plants

15. 2) Lipids Made of C, H, O --- (C to H ratio higher than 2 to 1)
Monomer: Glycerol & 3 fatty acids
Function: 1) Store energy 2) Insulation 3) Protection
EX. Fats and Oils

16. 3) Proteins Made of C, H, O, N, Sulfur Monomer: Amino Acid
20 AA
Function: 1) Build Muscle 2)Transportation (blood -- hemoglobin) ) Speed up chemical reactions (enzymes)

17. 4) Nucleic Acids Made of C, H, O, N, Phosphorus Monomer: Nucleotide
Function: Store genetic information
EX. DNA (Deoxyribose Nucleic Acid) – Master
RNA (Ribose Nucleic Acid) -- Copy of DNA

19. 2.4 Chemical Reactions and Enzymes
Chemical reaction = changes one set of chemicals into another set of chemicals
Chemical reactions have two parts:
Reactants
Products
CO2 + H2O  H2CO3
Reactants Product

20. Enzymes Enzymes are proteins that act as a biological catalyst.
Catalyst: a substance that speeds up the rate of chemical reaction
Enzymes speed up chemical reactions that take place in the cell.

21. Enzyme Action The enzyme-substrate complex
Enzymes are substrate specific.
They act like a lock and key.
Enzymes will only catalyze their substrates.
Regulation of Enzyme Activity
Enzymes can be affected by:
Heat pH
Concentration of Substrate
Proteins that turn enzymes “on” and “off”

22. Example of what an enzyme does!
How enzymes work
Potato + Peroxide  water + oxygen (catalase)

23. Where are enzymes? Enzymes regulate many chemical reactions such as:
Photosynthesis
Cellular respiration
Digestion
Enzymes are reusable
Once they work with one substrate they release and go to another substrate.