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Chemistry of Life
Small to large
Atoms
Element
Molecule
Macromolecule
Cells
Tissues
Organs
Organism
Small to large
Atom: Smallest possible particle of an
element
Element: A pure substance that can not be
broken down into other substances.
Molecules: Two or more atoms held
together by bonds
Macromolecule: a very large molecule,
Protein, carbohydrate, Lipid, Nucleic Acid
Cells: Basic unit of living matter
Chemistry
An atom contains; protons, neutrons,
and electrons
Atomic number: the number of protons
found in the nucleus of an atom
Periodic Table of Elements: An
arrangement of elements based on
their atomic number and mass
Elements are also placed due to the
number of electrons in the outer shell
Electrons and bonding
The number of electrons in the outer shell
determines how an element will react with
another.
Elements want to have “full” outer shells.
To have a full outer shell an element will
either share or transfer electrons
Ionic Bonding: elements transfer electrons
Covalent Bonding: elements share electrons
Water properties
Water
All living things are dependent on water
Cells are 70% to 95% water
Water is the only compound found on earth
in all 3 forms
Water is one oxygen covalently bonded to
two hydrogen's.
Although this is a covalent bond the oxygen
pulls the shared electrons closer to itself
making it more negative and making the
hydrogen more positive.
Water structure
Waters life-supporting properties
Cohesion: The
tendency of
molecules of the
same kind to
stick to one
another.
Important in
plants because as
water evaporates
it pulls itself
upward in plants.
Adhesion:
Attraction that
occurs between
unlike molecules.
Important
because water
sticks to the
sides of the plant
tubes and helps
combat gravity.
Waters life-supporting
properties
Temperature moderation: Water has
a very strong ability to resist change
in temperature due to hydrogen
bonding between molecules
Water allows for temperature
regulation of the world by staying
cool in the summer and warm in the
winter
Waters life-supporting properties
Ice: the solid form of water
that is lower density than
the liquid form. As water
freezes the molecules move
further apart.
Important because it allows
animals to continue to live
under frozen water instead
of being frozen from the
bottom up.
Waters life-supporting properties
Water has a great ability to dissolve
other substances.
Water is the universal solvent
Solvent: The substance that dissolves
another substance
Solute: The substance that is being
dissolved
Solution: A uniform mixture of two or
more substances.
Acids, Bases, Buffers,
Ph
pH Scale
Water sometimes breaks into ion’s of
H+ and OH-
Hydrogen ion(+) and Hydroxide ion(-)
These ions are what determine whether
something is an acid or base.
The pH scale is an exponential scale
showing acids and bases.
Ph Scale
Scale from 0 to 14
each step is 10x
more than the
next
0-6 is Acidic
7-8 is neutral
8-14 is Basic
LE 2-15
pH scale
H+
H+
H+

H+ OH
+
OH H
H+
Lemon juice, gastric juice
H+
H+
Grapefruit juice, soft
drink
Acidic solution
Tomato juice
Human urine
OH
OH

H+ OH
OH OH
H+
H+
H+
H+
Neutral solution
NEUTRAL
[H+[

Pure water
Human blood
Seawater
Milk of magnesia
Milk of magnesia
Household ammonia
OH
OH
OH
OH
H+
H+
OH
OH
Basic solution
Household bleach
Bleach
Oven cleaner
Acids
An acid is any substance that gives off
H+ to the solution
Ex: lemon juice, stomach acid
pH scale
H+
H+
OH
H+

H+
OH
H+
H+
H+
Acidic solution
H+
Bases
A base is a compound that removes H+
from the solution by giving off OH- to
bond with the H+
Ex: Soap, Bleach, Oven cleaner
Milk of magnesia
Household ammonia
OH
OH
OH
OH
H+
H+
OH
Household bleach
OH
Basic solution
Oven cleaner
Buffer
Cells are very sensitive to H+ and OH- ions.
Even a slight change in pH will affect a cell.
A buffer will accept H+ ions when they are
too high and will donate H+ when they are
too low.
Blood is a great example of a buffer
Tomato juice
Human urine
OH
OH
H+ H+ OH
OH OH
H+
H+
H+
Neutral solution
NEUTRAL
[H+[

Pure water
Human blood
Seawater
Chemical Reaction
The breaking of old and forming of new
bonds to make new chemical
substances.
Reactant: The starting materials
Product: The ending materials
Reactants
Product
Chemical reaction
In a chemical reaction the atoms
are not destroyed or created, just
rearranged.
H + H + O = H2O
Ions
Ions are created when an electron is
lost or gained
Elements that lose an electron are
positive ions (H+) due to the loss of a
negative charge.
Elements that gain an electron are
negative ions (H-) due to the gaining of
a negative charge
Chemistry of Life
Carbon is the one element required for life
Any Carbon based molecule is considered an organic
molecule
Each of the four macromolecules start with Carbon as the
basis.
Carbohydrates
Lipids
Proteins
Nucleic acids
Macromolecules
Carbohydrate: Complex sugars made up of Carbon,
Oxygen and Hydrogen
Starch: a large chain of sugars
Energy source of cells
Macromolecules
Lipids: Water avoiding compound made up of Carbon and
hydrogen chains
Cholesterol: An essential lipid molecule needed for cell
membranes.
Lipids act as a barrier that contains the liquid parts of the
cell. They also act as chemical messengers in the form of
hormones.
Macromolecules
Proteins: A large molecule made up of amino acids
Amino acid: A small molecule that is made up of
Carbon, Hydrogen, Nitrogen, and Oxygen.
Proteins are large chains of amino acids that bond
together and then fold to create useable cell parts.
Proteins also make up enzymes which speed up
chemical reactions.
Macromolecules
Nucleic Acids: A large molecule made up of smaller
molecules called nucleotides.
Nucleotides: Small molecules made up of a sugar, a
nitrogen base, and phosphate
Nucleic acids are what our DNA or genetic material is
made of
With out nucleic acids our body would not have
directions and could not function.
Proteins and Enzymes
Function of Proteins
Made up of amino acids
Responsible for most day to day
functions of all cells
Amino acids link together and
form a long chain
Protein Shape
The long Amino acid chain folds to make the protein
useable
A proteins shape is changed by its surroundings
A protein that is outside of its normal environment
will be denatured (misshapen)
Proteins to Enzymes
A protein sometimes
works as an enzyme
An enzyme speeds up
chemical reactions in
our bodies
An enzyme speeds up a
reaction by making it
easier.
This is done by
lowering the activation
energy
Enzyme
Enzyme: A protein that speeds up chemical reactions