Biology, Seventh Edition
Solomon • Berg • Martin
Chapter 3
The Chemistry of
Life:
Organic Compounds
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Organic compounds
• Carbon atoms covalently bonded
form the backbone of the molecule
• Very simple carbon compounds are
considered inorganic if carbon is not
bonded to another carbon or
hydrogen
• Carbon dioxide is an example of
inorganic carbon
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Carbon forms four covalent bonds,
producing many shapes
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Isomers: compounds with the
same molecular formulas, but
different structures
• Structural isomers
• Geometric isomers
• Enantiomers
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Isomers
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Functional groups
• Groups of atoms that determine the
types of chemical reactions and
associations
• Most readily form associations with
with other molecules
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Functional
groups
•
•
•
•
•
•
Hydroxyl
Carbonyl
Carboxyl
Amino
Phosphate
Sulfhydryl
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Polymers
• Most macromolecules are polymers
• Produced by linking monomers
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
A simple
polymer
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Carbohydrates
• Sugars
• Starches
• Cellulose
• Carbohydrate means hydrate
(water of) carbon
• Reflects 2:1 ratio of hydrogen to
oxygen
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Monosaccharides
• Contain three to seven carbon items
• Glucose most abundant
monosaccharide
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Monosaccharides, 2-D structures
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Disaccharide
• “Two sugars”
• Two monosaccharide rings joined by
a glycosidic linkage
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Derivatives of monosaccharides
are important biological
molecules
• Carbohydrates may combine
with proteins to form
glycoproteins
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Lipids
• Heterogeneous group of compounds
• Consist mainly of carbon and
hydrogen
• Some are important hormones and
some are used for energy storage
• Soluble in nonpolar solvents, such as
ether, and relatively insoluble in water
• Important groups include fats,
phospholipids, carotenoids, etc.
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Triacylglycerols (fats)
• Most abundant lipids in living
organisms
• When metabolized, yield twice as
much energy as carbohydrates
• Carbohydrates and proteins can be
transformed by enzymes into fats
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Triacylglycerol, the main storage lipid
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Saturated fatty acids contain maximum
possible number of hydrogen atoms
• Unsaturated fatty acids include one or
more adjacent pairs of carbon atoms
joined by a double bond
• Monounsaturated fatty acids—one
double bond
• Polyunsaturated fatty acids—more
than one double bond
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Phospholipids
• Amphipathic lipids
• Two ends differ physically and
chemically
• Uniquely suited to function as
fundamental components of cell
membranes
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
A phospholipid and a phospholipid bilayer
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Carotenoids
• Orange and yellow plant
pigments
• Classified with lipids
• Play a role in photosynthesis
• Consist of isoprene units
• Animals convert to vitamin A
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Isoprenederived
compounds
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Steroid
• Carbon atoms in four attached
rings
• Consist of isoprene units
• Cholesterol, bile salts, etc.
• Involved in regulating metabolism
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Proteins
• Macromolecules composed of
amino acids
• Most versatile cell components
• Most enzymes are proteins
• Proteins largely determine what a
cell looks like and how it
functions
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Four levels of organization
• Primary structure is the amino acid
sequence
• Secondary structure results from
hydrogen bonding
• Tertiary structure depends on
interactions among side chains
• Quaternary structure results from
interactions among polypeptides
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Primary structure of a polypeptide
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Secondary
structure
of a protein
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Tertiary structure
of a protein
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Quaternary
structure of
a protein
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Nucleic acids
• Transmit hereditary information
• Determine what proteins a cell
manufactures
• Two classes found in cells
–Ribonucleic acid (RNA)
–Deoxyribonucleic acid (DNA)
• Polymers of nucleotides
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
• Components of nucleotides
• Five-carbon sugar
–Deoxyribose (DNA)
–Ribose (RNA)
• One or more phosphate groups
• Nitrogenous base of either a
double-ring purine or a single-ring
pyrimidine
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Components of nucleotides
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
RNA,
a nucleic
acid
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Biology, Seventh Edition
CHAPTER 3 The Chemistry of Life: Organic Compounds
Classes
of biologically
important
organic
compounds
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