Section 1:
Atoms, Elements and Compounds

Elements
• pure substances that cannot be broken down
chemically

There are 4 main elements that make up 90% of the
mass of living things:
• Carbon – C
• Oxygen – O
• Hydrogen – H
• Nitrogen - N
 Each
element has a chemical symbol


Atoms are the
simplest particle
of an element.
The properties
of atoms
determine the
properties of the
matter they
compose

Atomic Structure:
• Nucleus: the central region of an atom
 Made of protons (+) and neutrons
(neutral)
 The number of protons in an element = the
atomic number
• Electrons: have a negative charge that
balances the protons
• Found in energy levels around the
nucleus
Energy
Level
Neutron
Proton
Electron
Nucleus
 Compounds
are pure substances made
of two or more elements
• Shown in chemical formulas
 Ex: H2O  always 2H for 1O
• The goal of making compounds is to make atoms
stable
 Compounds
are held together by bonds
• Covalent bonds: share electrons
• Ionic Bonds: electrons are transferred
 Results in ions  atoms with a full positive or
negative charge
 Create
Covalent
Bonds
Ionic
Bonds
a Venn
Diagram comparing
and contrasting
Covalent and Ionic
Bonds.
 Stand
Up
 Touch your right elbow to your left knee
 Then touch your left elbow to your right
knee.
 Repeat 9 more times
Section 2:
Chemical Reactions
 Chemical
Reactions
• the process through which chemical bonds are
broken or made (and sometimes both!)
6H2O + 6CO2 + energy  C6H12O6 +6O2
Reactants: what you put in
Products: what you get out

Activation Energy
• energy to start a reaction

Catalysts
• reduce the amount of
activation energy.
• Enzymes: catalysts
found in living things
Visual Concept
Section 3:
Water & Solutions

Solution: a mixture in which one or more substances
are uniformly distributed in another substance
• Solute: the substance dissolved in a solution
• Solvent: the substance that does the dissolving

Concentration: measurement of the amount of solute in
a fixed amount of solution
• 2% salt = 2g of salt in enough water to make 100mL
• Saturated Solution: is a solution in which no more solute can
dissolve
Section 4:
The Building Blocks of Life
 Organic
Compounds:
made mostly of carbon
atoms
 Inorganic
Compounds:
do not contain carbon
 Carbon
itself:
can bond with
• It can form straight chains
• It can form branched
chains
• It can form rings
 Monomers: building
blocks of organic
molecules
 Polymer: molecule made of multiple
monomers that are linked together
 Macromolecules: large polymers
• Ex: carbohydrates, lipids, proteins and nucleic
acids


Condensation Reaction:
monomers are linked to
polymers and water is
released
Hydrolysis: break down of
polymers using water
• The reverse of a condensation
reaction
4
Molecules of Life
• Carbohydrates (sugars)
• Proteins (enzymes)
• Lipids (fats)
• Nucleic Acids (DNA and RNA)

Carbohydrates
 Organic compounds made of
carbon, oxygen and hydrogen.

Monosaccharides:
 monomer (building block) of a
Glucose
carbohydrate
 Examples: Glucose & Fructose
○ All 3 monomers have the same
formula  C6H12O6, but they each
have different structures - isomers
Fructose
 Disaccharides: double
sugar (two
monosaccharides bonded together)
• The reaction that joins the two monosaccharides
together is called a condensation reaction
• Examples:
Sucrose
Lactose
Sucrose
 Polysaccharides: made
of 3 or more
monosaccharides bonded together
• Examples:
 Glycogen (in animals): energy storage
 Stored in liver and muscle, made of glucose molecules
 Starch (in plants): energy storage
 Made of glucose molecules
 Cellulose (in plants): used for structure  cell wall


Proteins
• organic compounds made of
carbon, hydrogen, oxygen
and nitrogen
Monomer = amino acids
• 20 different amino acids
• Functional groups of amino acids:
 -COOH, NH2
• What gives the amino acid its
specific identity is it’s
R-group
 R-groups can be simple or complex
 Dipeptides
are two amino acids bonded
together
• The bond between amino acids is called a
peptide bond
• Peptide bonds are formed during a
condensation reaction


Polypeptides: very
long chains of amino
acids
Form larger proteins,
which are usually
made of more than
one polypeptide chain
 Enzymes: Protein
(or RNA) molecules that act
as biological catalysts
 Temperature
and pH effect an enzyme’s activity
 How
enzymes work:
• Induced Fit Model of Enzyme Action
 Enzyme reactions depend on the physical fit between the
enzyme and its substrate (the reactant being catalyzed)
 Active Site: portion of the enzyme that the substrate fits into
 The linkage between the enzyme and the substrate causes a
slight change in the enzyme’s shape which puts a strain on the
substrate bonds
 The enzyme releases the products and remains unchanged
 Lipids: large, nonpolar
molecules
• DO NOT dissolve in H20
organic
 Building blocks of lipids:
• Glycerol:
 Functional group = -OH
• Fatty Acids: unbranched
carbon-chains
 Functional group = -COOH
• Fatty Acids Continued:
 Fatty acids can be saturated
 (each carbon is bonded to 4 other things – “full”)
 Fatty acids can be unsaturated
 (when the carbon atoms form double bonds with each other
in the carbon chain)

Types of Lipids:
• Triglycerides: 3 fatty acids attached
to a glycerol
• Phospholipids: 2 fatty acids attached to a glycerol, with a
phosphate attached to the 3rd carbon of the glycerol
 Makes-up the cell membrane of cells
Hydrophilic head
2 Fatty acid tails
 Nucleic
Acids: store and transfer genetic
information
• 3 parts of a nucleic acid:
 Phosphate Group
 Sugar
 Nitrogenous Base
• Three combined forms the nucleotide
• 2 types of Nucleic Acids
 DNA: stores genetic information for an organism
 RNA: stores and transfers information from DNA that
is needed to make proteins