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Molecules of Life---Whoa!
Biology
9-9-10
Overview
• It’s all about the Carbon
• Major Biological Molecules
 Name
 Function
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•
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Carbohydrates
Proteins
Lipids
Nucleic Acid
Organic vs. Inorganic
• Organics




Contain CARBON
Covalently bonded
Large molecules
Come from something that is now or once was
alive
Organic vs. Organic
• Inorganic




No Carbon
Ionic bonded
Tiny
Come from the earth’s crust
Carbon

Carbon atoms have
four valence electrons,
allowing them to form
strong covalent bonds
with many other
elements, including
hydrogen, oxygen,
phosphorus, sulfur,
and nitrogen.
Carbon
 Carbon atoms can also bond to each other,
which gives carbon the ability to form millions
of different large and complex structures.
Carbon Bonds
 Carbon-carbon bonds can be single, double,
or triple covalent bonds.
Macromolecules
• Organic molecules found in living cells
• Smaller molecules can combine to form
VERY large chains: Polymerization
Macromolecules
• The smaller molecules are called
monomers.
• Monomers in a polymer may be identical or
different.
• Macromolecules are grouped according to
their chemical composition.
Behind Door #1 We Have Our
First Biological Molecule…
CARBOHYDRATES!!!
Carbohydrates
• What is the main function???
• ENERGY!!!
• Plants, some animals, and other
organisms also use carbohydrates for
structural purposes.
Carbohydrates
Carbohydrates are compounds made up
of carbon, hydrogen, and oxygen atoms,
usually in a ratio of 1 : 2 : 1.
Carbohydrates
• 2 different kinds:
 Simple Sugars: go right to bloodstream
after consumption
 Complex Carbohydrates: require
digestion; can be hours before body can
use it.
Simple Sugars
• Monosaccharides
• Relatively small in size
• Glucose
 Blood sugar
• Sucrose
 Table sugar
• Fructose
 Fruit sugar
• Lactose
 Found in milk
Complex Carbohydrates
• Polysaccharides: large macromolecules formed
•
•
from monosaccharides.
In animals….
Glycogen: many animals store excess sugar
here. Glycogen breaks down to glucose and is
released into the blood when needed. In
muscles, glycogen provides energy for
contraction.
Complex Carbohydrates
• In plants…
• Excess sugar plants make is stored as
starch.
• Plants also make cellulose which gives
plants their strength and rigidity.
 indigestible for humans
Behind Door # 2…..
LIPIDS!!!
Lipids
• What are functions of lipids?
• Protection: fat pads over heart, kidneys, etc.
•
•
•
•
•
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Serves as cushions over organs.
Hormones and Steriods made by the body:
estrogen, testosterone
Cholesterol found in cell membranes
Lubrication (joints): act like gel packs between
joints.
Energy Storage
Important part of biological membranes (cell
membranes)
Waterproof coverings
Lipids
• What are lipids made of?
• Mostly from carbon and hydrogen atoms
• Lipids are generally NOT soluble in water
 What is another word for that property?
• HYDRAPHOBIC
Lipids- Fatty Acids
• Fats- SATURATED
• Solids at room temperature; come from animals;
•
•
•
•
single chain C molecules
CH3-CH2-CH2-CH2-CH3
Oils- UNSATURATED/ POLYUNSATURATED
Liquid at room temperature; come from plants;
multiple bond chains of C
CH2=CH-CH=CH-CH=CH2
Lipids
• Hydrogenation
• Taking an unsaturated lipid and turning it
into a saturated lipid by adding Hydrogen
(H) to the lipid.
• Double bonds are broken and replaced by
single bond H to Carbon.
• Tends to produce transfats.
Lipids
• Lipids can be formed when a glycerol
molecule combines with fatty acids
Lipids
Behind Door #3….
Nucleic Acids!!!
Nucleic Acids
• What is their function?
• To store and transmit hereditary/ genetic
•
•
•
•
information
DNA Deoxyribonucleic acid: biological blueprint
RNA Ribonucleic acid: carries out instructions from
DNA
Nucleic Acids
• Nucleotides:
•
•
•
•
monomers that make
up nucleic acids
(polymers).
Nucleotide structure:
5-carbon sugar
Phosphate group
(-PO4)
Nitrogenous base
Nucleic Acids
•
•
•
•
•
•
Main Nucleotides:
Adenine (DNA and RNA)
Guanine (DNA and RNA)
Cytosine (DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
And Finally… Behind Door
#4…
PROTEINS!!!
Proteins
• What are functions of Proteins??
• Structural: muscle, hair
• Enzymes--pure protein: catalysts which
allow chemical reactions to take pace at
normal body temperature.
• Transport: substances attach to protein to
enter cells.
Proteins
• Proteins are made of compounds called
•
•
•
•
amino acids.
All proteins contain C, O, N, H
Amino acids are made up of an amino
group (-NH2) and a carboxyl group
(COOH).
How do amino acids differ?
R-group
Proteins
Proteins
• What is an R-group?
• This is a generic notation for some type of
Carbon group.
• The R-group can also be a Hydrogen.
• In this case it is whatever is attached to the
amino and carboxyl groups that make up
the amino acid.
Proteins
Proteins
• How many amino acids exist in nature?
• More than 20 different types (because of
R-group)
• Proteins are among the most diverse
macromolecule because of all the possible
arrangements of amino acids.
Proteins
•
•
•
•
•
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Proteins are polymers of amino acids.
Peptides/ polypeptides
Small, short strings of amino acids
Covalently bonded
Protein
A functional molecule built from one or
more polypeptides
• Large; long chains of amino acids
Proteins
• Complete Proteins: Animal protein
molecules contain repeated use of all 20
different amino acids.
• Incomplete Proteins: Most plant sources
produce proteins that do not contain all 20
amino acids.
 Vegetarians need to eat a variety of plants in
order to get the amino acids they need for
their own protein synthesis.
Proteins:
Levels of Organization
• Proteins can have 4 different structural
levels of organization.
• Primary Structure: is the sequence of its
amino acids.
• Secondary Structure: the folding or
coiling of a peptide chain. Typically done
by hydrogen bonding.
Proteins:
Levels of Organization
Proteins:
Levels of Organization
• Tertiary Structure: the complete 3-D
arrangement of the polypeptide chain.
• Fourth Level of Structure: proteins with
more than one chain; fourth level describes
the way the different polypeptide chains
are arranged with respect to each other.