Transcript Chapter 3 Biochemistry

The Chemistry of Organic Molecules
Chapter 3
Mader: Biology 8th Ed.
Outline
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Organic vs Inorganic
Functional Groups and Isomers
Macromolecules
– Carbohydrates
– Lipids
– Proteins
– Nucleic Acids
Mader: Biology 8th Ed.
Organic Molecules
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Organic - Living
Inorganic - Nonliving
– Organic molecules contain both carbon
and hydrogen. Four categories:
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids
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Carbon Atom
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Carbon atoms contain a total of 6 electrons,
with only four in the outer shell.
– Very diverse as it can bond with up to four
different elements.
 Often shares with other carbon atoms,
producing long carbon chains.
 Hydrocarbons are chains of carbon
bonded only to hydrogen atoms.
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Functional Groups and Isomers
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Functional groups are specific combinations
of bonded atoms that always react in the
same manner, regardless of the particular
carbon skeleton.
– Determine polarity of organic molecule.
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.
Isomers
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Isomers are organic molecules that have
identical molecular formulas but a different
arrangement of atoms.
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Macromolecules
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Carbohydrates, lipids, proteins, and nucleic
acids are referred to as macromolecules
because of their large size.
– Polymers are made up of monomers.
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Dehydration - Removal of water molecule.
Hydrolysis - Addition of water molecule.
– Enzymes speed up reactions.
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Carbohydrates
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Used as immediate energy sources.
– Monosaccharides - Single sugar molecule.
 Glucose, ribose, deoxyribose
– Disaccharides - Contain two
monosaccharides joined during
dehydration reaction.
 Sucrose
– Polysaccharides - Polymers of
monosaccharides.
 Starch, cellulose, chitin
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Lipids
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Insoluble in water due to hydrocarbon chains.
Fats
– Glycerol - Contains three OH groups.
 Triglycerides - Three fatty acids attached
to each glycerol molecule.
 Fatty acid consists of long
hydrocarbon chain.
 Saturated - No double bonds.
 Unsaturated - Double bonds.
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Fat and Fatty Acids
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Lipids
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Phospholipids
– Instead of third fatty acid attached to
glycerol as in fat, there is a polar
phosphate group.
 Hydrophilic heads and hydrophobic tails.
 Arrange themselves so polar heads
are adjacent to water.
 Bulk of cell plasma membrane
consists of phospholipid bilayer.
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Phospholipids
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Lipids
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Steroid
– Have skeletons of four fused carbon rings.
 Cholesterol, testosterone, estrogen
Waxes
– Long-chain fatty acid bonds with a longchain alcohol.
 High melting point
 Waterproof
 Resistant to degradation
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Proteins
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Functions
– Support
– Enzymes
– Transport
– Defense
– Hormones
– Motion
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Proteins
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Amino acids are subunits of proteins.
– Bond to a hydrogen atom, an amino group
-NH2, an acidic group -COOH, and an R
(remainder) group.
 Peptide Bond - Covalent bond between
two amino acids.
 Peptide - Two or more amino acids
bonded together.
 Polypeptide - Chain of many amino
acids joined by peptide bonds.
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Proteins
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Protein Structure
– Primary - Sequence of amino acids.
– Secondary - Polypeptide coils or folds in a
particular fashion.
– Tertiary - Folding and twisting that results
in final three-dimensional shape of a
polypeptide.
– Quaternary - Consists of more than one
polypeptide.
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Protein Folding Diseases
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As proteins are being synthesized,
chaperones bind and prevent incorrect
interactions.
– Mad cow disease is an example of a
category of fatal brain diseases TSEs,
that could be due to misfolded proteins.
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Nucleic Acids
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Polymers of nucleotides with very specific
cell functions.
– DNA (seoxyribonucleic acid)
 Doublestranded
– RNA (ribonucleic acid)
 Singlestranded
Every nucleotide is made up of phosphate,
pentose sugar, and a nitrogenous base.
– Complementary base pairing
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DNA
Mader: Biology 8th Ed.
RNA
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Nucleic Acids
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ATP (adenosine triphosphate) is composed
of adenine and ribose.
– In cells, the terminal phosphate bond is
hydrolyzed to give the molecule ADP
(adenosine diphosphate) and a phosphate
molecule.
 Releases energy
Mader: Biology 8th Ed.
Review
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Organic vs Inorganic
Functional Groups and Isomers
Macromolecules
– Carbohydrates
– Lipids
– Proteins
– Nucleic Acids
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.