Transcript Nucleic Acids

The Macromolecules of Cells:
Carbohydrates
Lipids
Proteins
Nucleic Acid
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Organic Molecules
* Organic molecules are found in
living things (vs. Nonorganic)
* Referred to as “macromolecules”
-- Carbohydrates
-- Lipids
-- Proteins
-- Nucleic Acids
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Organic molecules are made of carbon and can
form a huge variety of carbon backbone chains.
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Macromolecules (polymers) are formed
from smaller building blocks called
monomers.
Polymer
carbohydrates
proteins
nucleic acids
Lipids
Monomer
monosaccharides
amino acids
nucleotides
“none”
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Carbohydrates
Carbohydrates (sugars) serve as
1) quick energy and short-term
energy storage
2) they play a structural role in
plants, bacteria, and insects
3) many end in the suffix “ose”
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Monosaccharides
• Monosaccharides are sugars that are
made up of only one sugar.
• There are only 3 monosaccharides
Glucose Fructose
Galactose
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Monosaccharide -one sugar carbohydrate
Glucose
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Disaccharides
• Disaccharides are made out of two simple
sugars (monosaccharides)
Sucrose (table sugar) -- glucose + fructose
Maltose (malt sugar) -- glucose + glucose
Lactose (milk sugar) -- galactose + glucose
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A disaccharide is made from linking
two monosaccharides together.
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Reactions
• The making or breaking of disaccharides
uses a molecule of water
• Condensation: reaction makes a
disaccharide from two monosaccharides and
removes a water molecule in the process.
• Hydrolysis: reaction breaks down a
disaccharide by adding a water molecule to
satisfy the exposed bonding sites on the two
new monosaccharides.
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Condensation Reaction
• Water is removed to
allow the two sugars
to bond together.
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Hydrolysis Reaction
• Water is added so Oand OH+ can be
added to exposed
bonding sites.
• Satisfies bonds
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Polysaccharides
Larger sugars are made from linking
many glucose molecules
Starch
Glycogen
Cellulose
Chitin
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Examples of Polysaccharides:
starch -- (helical structure)
energy storage in plants
glycogen
(highly branched)
quick energy for animals
cellulose -- (unbranched) found in plants for structure. It is
not available as an energy source because of structure.
Chitin – found in the exoskeleton of insects and
crustaceans
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Starch
• Starch is a storage
molecule for
plants. It is stored
in structures called
plastids.
• Starch is high in
energy and is
stored energy for
the plant.
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Glycogen
• Glycogen is a
molecule that is
used by animals
for temporary
storage of energy.
If not utilized,
energy will be
stored as fat.
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Chitin
• Chitin is a
polysaccharide
found in
exoskeletons of
crustaceans and
insects.
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Cellulose
• Polysaccharide
found in the cell
walls of plants.
Strong molecule
used for structure
and support of the
plant cell.
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Lipids
*Lipids serve as long-term energy stores
in cells, form membranes, and serve as
hormones and insulation.
Lipids do not dissolve in water!!!
Main reason why lipids are classified
together; all other molecules are
soluble in water
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Structure of Triglycerides
Formed from a glycerol molecule and
three fatty acid molecules.
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Fatty Acid Chains
Fatty acids are long chains of carbons
with many hydrogens attached. Full
of energy since all bonds are potential
energy for an organism.
Fatty acids may be saturated fatty acids
or unsaturated fatty acids.
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Saturated vs. Unsaturated
“bad for you”
• Saturated Fats have no
double bonds
• Found in tropical oils
and animal fats
• All carbons are
“saturated” with
hydrogens.
• Straight chains
• Solid at room temp.
“good for you”
• Unsaturated Fats have
varying numbers of
double bonds
• Common in plants
• All carbons are not fully
bonded with hydrogens
• Chains are bent at
double bonds
• Liquid at room temp.
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Some lipids are phospholipids that
form cell membranes. These only
have two fatty acids chains.
Glycerol head is hydrophilic -- loves water
Fatty Acid tails are hydrophobic -- hate water
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Other lipids are steroids -no fatty acid chains.
Examples:
Steroids -- Cholesterol (thickens arteries and is
important in cell membrane)
Hormones (estrogen and testosterone)
Waxes
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Proteins
Proteins:
1. Serve as structural proteins (cartilage,
fingernails, hair, etc.)
2. Act as enzymes to speed reactions
3. Serve as transport carriers
4. Act as antibodies
5. Allow materials to cross membranes
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Proteins are polymers of amino acids.
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Water is removed when joining
two amino acids.
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Proteins have levels of organization.
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Protein Organization
• Primary Structure (1°) -- linear chain of amino
acids. Number and sequence of amino acids
varies.
• Secondary Structure(2°) -- shortening of
amino acid chain by coiling or pleating
• Tertiary Structure (3°) -- further folding of
chain to create a more compact structure
• Quaternary Structure (4°) -- only some
proteins have this structure which is two or
more chains bonded together.
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Nucleic Acids
Nucleotides are monomers of nucleic acids.
Examples include Deoxyribonucleic Acid
(DNA) and Ribonucleic Acid (RNA).
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DNA is double-stranded, with
complementary base pairing.
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