The Chemistry of Life
The Nature of Matter
Atoms


All things are made of matter
Atom -basic unit of all matter
 Normally it is electrically
neutral (no charge)
 Parts of the atom
 Protons
 Neutrons
 Electrons
The Nature of Matter
Protons

Protons
 + charged particle
 In the center of the
atom-nucleus
 Heavy
The Nature of Matter
Neutrons

Neutrons
 Neutrally charged
particle
 In the nucleus
 Heavy
The Nature of Matter
Electrons

Electrons
 - charged particle
 In constant motion
in orbitals
surrounding the
nucleus
 Light
The Nature of Matter
Elements


Element-pure substance that consists of
just one type of atom
Atomic Number=
# of protons=#electrons
114 in the periodic table –
 Only about 2 dozen commonly found
6
in living things

Atoms have a 1 or 2 letter
symbol
C = carbon
 N = nitrogen
 H = hydrogen
 O = oxygen, etc.

C
Carbon
12.011
Atomic Mass=
# of protons + # of neutrons
Where is Sodium?
What is its atomic number?
The Nature of Matter
Isotopes
•Isotopes--atoms of same element w/ a different # of
neutrons
Isotopes of Carbon
Nonradioactive carbon-12 Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
Radioactive carbon-14
6 electrons
6 protons
8 neutrons
The Nature of Matter
Radioactive Isotopes

Isotope with unstable nucleus
due to extra neutrons
 Break down at a constant rate
 Give off dangerous radiation
 Have uses too
 C-14 dating- determines
ages of rocks by analyzing
isotopes found in them
 Cancer treatment
The Nature of Matter
Compounds



In nature, most elements are found
combined with other elements in nature.
A chemical compound is a substance
formed by the chemical combination of two
or more elements in definite proportions.
The atoms in compounds are held together
by chemical bonds.
The Nature of Matter
Bonding


Bonding -for some atoms to be stable they
must gain, lose, or share electrons with
another atom.
2 types of bonds
-Ionic
-Covalent
The Nature of Matter
Ionic Bonds





Ionic bonds - electrons transferred from
one atom to another
Valence electrons- electrons in the last
energy level of an atom
Formation of ions-negatively or positively
charged atoms
The oppositely charged ions attract,
forming the ionic bond
NaCl has ionic bonds
Ionic Bonding
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
The Nature of Matter
Covalent Bonds



Covalent bonds --sharing
electrons
Stronger than ionic
Molecule--formed when
atoms are joined in a
covalent bond
Properties of Water




Water covers ¾ of Earth’s
surface
Most abundant molecule in living
things
Universal solvent…dissolver of
many substances found on Earth
Connects all parts of the world
with others.
Properties of Water
Polar Molecule




Water has covalent bonds
Water bonds are polar- unequal
sharing of electrons.
Oxygen “pulls” harder on negative
electrons than H—gives O slight
negative charge.
**Water has polar, covalent
bonds
Properties of Water
Hydrogen Bonds



Polarity causes water
molecules to attract each
other like magnets
H (+) attracts O (-) forming
a hydrogen bond
Gives water special
properties
Properties of Water
Hydrogen Bonds


Hydrogen bonds are not as strong as
covalent or ionic
Waters ability to form multiple hydrogen
bonds is responsible for many of it’s special
properties


Cohesion – is an attraction between molecules
of the same substance
Adhesion – is an attraction between molecules
of different substances
Properties of Water
Solutions




Solutions occur when one substance is
dissolved in another.
Solute -gets dissolved
Solvent -does the dissolving.
Saltwater
What is the pH scale?

The pH scale
measures
how acidic
or basic a
solution is.
The pH scale

The pH scale is the concentration
of hydrogen ions in a given
substance.
Identifying Acids and Bases




Acids have a ph from 0-6
Lower pH value indicates a
stronger acid.
Bases have a pH from 8-14
Higher pH value indicates a
stronger base.
OH 

Definitions of Acids and Bases



An acid is a substance that breaks

into H  ions in an aqueous
solution.
A Base (alkaline) is a substance
that breaks into OH   ions in an
aqueous solution.
Note: aqueous solution is any
solution where H 2 O is the
solvent.
Did we Miss something??


What happens when the pH of a
substance is 7?
Ans: A pH level of 7 indicates a Neutral
Substance i.e: Water!
Test Your Knowledge
What is the range of an ACID on the pH
scale?
Ans: 0-6

What is the range of a BASE and what is
another name for a BASE?
Ans: 8-14, Alkaline

Characteristics Of Acids
Acids can be characterized by:
1.
A sour taste.
2.
It turns blue litmus paper red
3.
It tastes sour. Try drinking lemon juice (citric
acid)
Characteristics of Bases
A Base is characterized by:
1.
A bitter taste. (Milk of Magnesia)
2.
It feels slippery. (Soapy Water)
3.
It turns Red Litmus Blue.
Why Learn about Acids & Bases?



What do you think is the pH level of miami
dade county tap water?
The pH of a swimming pool must be
checked periodically. Why?
Is it important for Lakes & Rivers to
maintain a certain pH?
Today’s Experiment


Test the pH of Pepsi, tap water, and drain
cleaner
GOOD LUCK!!!
Properties of Water
Buffers


Human homeostasis-human
blood must be b/t pH 6.77.5
Body uses buffers, which are
weak acids or bases, to
neutralize sharp changes in
blood pH
Macromolecules
copyright cmassengale
32
Organic Compounds


Compounds that contain CARBON
are called organic.
Macromolecules are large organic
molecules.
copyright cmassengale
33
Carbon (C)


Carbon has 4 electrons in outer
shell.
Carbon can form covalent bonds
with as many as 4 other atoms
(elements).

Usually with C, H, O or N.

Example:
CH4(methane)
copyright cmassengale
34
Macromolecules




Large organic molecules.
Also called POLYMERS.
Made up of smaller “building blocks”
called MONOMERS.
Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleiccopyright
acids
(DNA and RNA)
cmassengale
35
Question:
How Are
Macromolecules
Formed?
copyright cmassengale
36
Answer: Dehydration Synthesis


Also called “condensation reaction”
Forms polymers by combining
monomers by “removing water”.
http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html
HO
H
HO
H
H2O
HO
H
copyright cmassengale
37
Question:
How are
Macromolecules
separated or
digested?
copyright cmassengale
38
Answer: Hydrolysis

Separates monomers by “adding
water”
HO
H
H2O
HO
H
copyright cmassengale
HO
H
39
Carbohydrates
copyright cmassengale
40
Carbohydrates


Small sugar molecules to large
sugar molecules.
Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
copyright cmassengale
41
Carbohydrates
Monosaccharide: one sugar unit
Examples:
glucose
glucose (C6H12O6)
deoxyribose
ribose
Fructose
Galactose
copyright cmassengale
42
Carbohydrates
Disaccharide: two sugar unit
Examples:
Sucrose (glucose+fructose)
 Lactose (glucose+galactose)
 Maltose (glucose+glucose)

glucose
glucose
copyright cmassengale
43
Carbohydrates
Polysaccharide: many sugar units
Examples: starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucose
glucose
glucose
glucose
cellulose
glucose
glucose
glucose
copyright cmassengale
glucose
44
Lipids
copyright cmassengale
45
Lipids




General term for compounds which are
not soluble in water.
Lipids are soluble in hydrophobic
solvents.
Remember: “stores the most energy”
Examples: 1. Fats
2. Phospholipids
3. Oils
4. Waxes
5. Steroid hormones
cmassengale
46
6. copyright
Triglycerides
Lipids
Six functions of lipids:
1. Long term energy storage
2. Protection against heat loss
(insulation)
3. Protection against physical shock
4. Protection against water loss
5. Chemical messengers (hormones)
6. Major component of membranes
(phospholipids)
copyright cmassengale
47
Lipids
Triglycerides:
composed of 1 glycerol and 3
fatty acids.
H
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
H-C----O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
O
fatty acids
H-C----O C-CH -CH -CH -CH
2
2
2
H
glycerol
copyright cmassengale
48
Fatty Acids
There are two kinds of fatty acids you may see
these on food labels:
1. Saturated fatty acids: no double bonds
(bad)
O
saturated
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
2. Unsaturated fatty acids: double bonds
(good)
O
unsaturated
C-CH2-CH2-CH2-CH
copyright cmassengale
49
Proteins
copyright cmassengale
50
Proteins (Polypeptides)


Amino acids (20 different kinds of aa)
bonded together by peptide bonds
(polypeptides).
Six functions of proteins:
1. Storage:
albumin (egg white)
2. Transport:
hemoglobin
3. Regulatory:
hormones
4. Movement:
muscles
5. Structural:
membranes, hair, nails
6. Enzymes:
cellular reactions
copyright cmassengale
51
Proteins
(Polypeptides)
Four levels of protein structure:
A.Primary Structure
B. Secondary Structure
C. Tertiary Structure
D.Quaternary Structure
copyright cmassengale
52
Primary Structure
Amino acids bonded together
by peptide bonds (straight
chains)
Amino Acids (aa)
aa1
aa2
aa3
aa4
aa5
aa6
Peptide Bonds
copyright cmassengale
53
Secondary Structure


3-dimensional folding arrangement of a
primary structure into coils and pleats
held together by hydrogen bonds.
Two examples:
Alpha Helix
Beta Pleated Sheet
Hydrogen Bonds
copyright cmassengale
54
Tertiary Structure



Secondary structures bent and folded
into a more complex 3-D arrangement
of linked polypeptides
Bonds: H-bonds, ionic, disulfide
bridges (S-S)
Call a “subunit”.
Alpha Helix
Beta Pleated Sheet
copyright cmassengale
55
Quaternary Structure
Composed of 2 or more
“subunits”
 Globular in shape
 Form in Aqueous environments
 Example: enzymes (hemoglobin)

subunits
copyright cmassengale
56
Nucleic
Acids
copyright cmassengale
57
Nucleic acids


Two types:
a. Deoxyribonucleic acid (DNAdouble helix)
b. Ribonucleic acid (RNA-single
strand)
Nucleic acids are composed of long
chains of nucleotides linked by
dehydration synthesis.
copyright cmassengale
58
Nucleic acids

Nucleotides include:
phosphate group
pentose sugar (5-carbon)
nitrogenous bases:
adenine (A)
thymine (T) DNA only
uracil (U) RNA only
cytosine (C)
guanine (G)
copyright cmassengale
59
Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Nitrogenous base
(A, G, C, or T)
Sugar
(deoxyribose)
C3copyright cmassengale
C2
60
DNA
double
helix
O
5
3
3
O
P
5
O
C
G
1
P
5
3
2
4
4
2
3
1
P
T
5
A
P
3
O
O
P
5
O
3
copyright cmassengale
5
P
61
Organic Macromolecules
Carbohydrates


Structure: subunit = sugars
Carbs are either


Sugars = monosaccharides
 sucrose, glucose, fructose
 short chains OR
Starches = polysaccharides
 sugars hooked together
 pasta, cellulose (plant cell walls)
 long chains
MONOSACCHARIDES
POLYSACCHARIDE
Organic Macromolecules
Carbohydrates

Function





Main source of energy for living things
Converted to ATP—gasoline for cells
Monosaccharides = immediate E
Polysaccharides = longer term E
Plants store carbs as cellulose—gives
their cells strength
Organic Macromolecules
Lipids

Structure: subunit = fatty acids and
glycerol
 C and H
 Fats, oils, waxes are lipids
 Saturated and Unsaturated fats
 Hydrophobic—”water-fearing”-not
dissolvable in water
FATTY ACIDS AND GLYCEROL
LIPID
Organic Macromolecules
Lipids

Function





Store energy for use later
Why should I care?
Hormones
Cell membranes
Waterproof covering (skin)

Organic Macromolecules
Nucleic Acids
Structure: subunit = nucleotides
 Nucleotides:
 5 C sugar
 Phosphate group
 Nitrogenous base
 DNA and RNA
NUCLEOTIDES
NUCLEIC ACID
Organic Macromolecules
Nucleic Acids
Function:
Store
and transmit
hereditary (genetic) info
Organic Macromolecules
Proteins

Structure: subunit = amino acids
 C, N, O, and H
 20 different amino acids form
1000’s of different proteins
AMINO ACIDS
PROTEINS
Organic Macromolecules
Proteins

Function






Enzymes-proteins that control chemical
reactions
Form bones and muscles
Forms hair and nails (keratin)
Part of cell membrane
Steak, eggs, nuts, cheese
PROTEINS ARE NOT SOURCES OF ENERGY!
ORGANIC MACROMOLECULES
C-C BONDS
LIPIDS
Subunit:
Glycerol and
fatty acids
Fats, oils
Waxes
Hydrophobic
Cell Membrane
Hormones
Energy storage
NUCLEIC ACIDS
Subunit:
Nucleotides
DNA and RNA
Store and carry
genetic
information
CARBOHYDRATES
Subunit:
Simple sugars
(monosaccharides)
Polysaccharides
are starches like
pasta and potatoes
1C: 2H: 1O
Both for energy
Cellulose-cell
Walls in plants
PROTEINS
Subunit:
Amino acids
Steak, eggs
peanuts
Help build
muscle, hair
and nails
Act as enzymes
Cell membrane
Chemical Reactions and Enzymes
Chemical Reactions




Everything occurring in an
organism based on chemical
reactions- process that changes
one set of chemicals into
another set
Slow (rusting) or fast (burning)
Breaking and remaking of
bonds
Reactants-products
Chemical Reactions and Enzymes
Chemical Reactions
Reactant(s)
Product(s)
carbon + oxygen
carbon dioxide + energy
CO2 + energy
C + O2
O
C
O
C
O
black solid
colorless gas
colorless gas
O
+ energy
Chemical Reactions and Enzymes
Energy in Chemical Reactions





Reactions involve changes in energy
Some reactions release energy and some
have to absorb it
ATP- form of energy absorbed or released
when bonds are made or broken
We get our ATP and organic macromolecules
for body processes from food.
Plants get it through?
Chemical Reactions and Enzymes


Some reactions are too slow or need lots of
activation energy (ATP) to occur.
Enzymes are proteins that decrease the activation
energy needed for these types of reactions to occur.


They lower the energy “hill” making these reactions easier
and faster
Digestion, nervous system signals, etc. all require
enzymes.
Activation energy
Reactants
Products
Chemical Reactions and Enzymes
Enzymes

Enzyme activity regulated by many
variables



pH
Temperature
Enzyme concentration
PRODUCTS
REACTANTS