Chemistry of Life

Chapter 6 page 141

Elements

• Everything on earth is made of elements– Rock– Flower– Water– Etc

• Definition– A substance that cannot be broken down into

simpler chemical substances

Elements in a human

• Only 4 of the 90 naturally occurring elements make up more than 96% of the mass of a human– O – C– H– N

Elements in the Human Body (percent by mass)

64%

19%

10%

3%2%1%1%

Oxygen

Carbon

Hydrogen

Nitrogen

Calcium

Phosphorus

Other elements

Atoms

• Definition– Smallest particle of an element that has the

characteristics of that element• Thus…

– Building blocks of elements

Structure of Atoms

• Nucleus– Contains:

• Protons positively charged• Neutrons no charge

• Energy Levels– Contain:

• Electrons negatively charged

Energy Levels

• Page 143– Electrons travel around nucleus in energy

levels• 1st level can hold 2 electrons• 2nd level can hold 8 electrons• 3rd level can hold 18 electrons

Oxygen

• 8 electrons

• 8 protons

• 8 neutrons– Draw an example of an oxygen atom

What is a compound?

• Water is not an element (H20)

• It’s a compound– Substance that is composed of two or more

different elements

Element Atomic Number Mass Number Charge Protons Neutrons Electrons

C 6  12 0 6 6 6

K 19 39 0 19 20 19

H 1 1 0 1 0 1

Na 11 23 +1 11 12 10

Cl           

N           

Substance Benedicts Test Iodine Test Type of Saccharide

Starch - + Poly

Dextrose  + - Mono

Apple      

Potato      

Karo Syrup      

7 - Up      

Table Sugar -  - Di

Lactose      

Glucose      

Organic CompoundElements in Compound Function Examples

Lipids p. 160

C:H:OGlycerol Molecule

and Fatty Acid Tails

Energy Storage, Protection, Insulation

Fats, Steroids,Waxes, Oils

Proteins p. 160-161

C:H:O:N and SulfurAmino Acids

Structure, Support, and

Facilitate Chemical Reactions

Muscle Tissue,

Enzymes

Carbohydrates p. 158 - 159

C:H:O1:2:1 ratio

C6H12O6 Energy for Cell

Monosaccharides,Disaccharides, and Polysaccharides (3)

1.Glycogen2.Starch

3.Cellulose

Nucleic Acidsp. 163

C:H:O:N:PPhosphate Group,

Sugar, Nitrogen Base

Store Genetic Information DNA and RNA

• Isomers – Compounds with the same formula but different structures:

Isotopes – Atoms of the same element with different #’s of

neutrons

• C-12– Has 6 protons and 6 neutrons

• C-13 – Has 6 protons and 7 neutrons

• C – 14– Has 6 protons and 8 neutrons

• Are C-13 and C-14 equal?

Reactants vs. Products

•C6H12O6 + C6H12O6 C12H22O11+ H2O

•2 H2O2 2 H2O + O2

• 6CO2 + 6H20 C6H12O6 + 6O2

Covalent Bonding

• Sharing Electrons

Ionic Bonding• Bond formed when electrons are transferred

• Catalyst– Speeds up chemical reactions

• Enzymes are catalysts

Acids have sour taste and are corrosive Bases have a slippery

feeling and a bitter taste

Chemical Reactions

• Bonds between atoms are formed or broken