1 Chemical Basis of Life Outline: The Chemical Basis of Life 1. Chemistry of Carbon 2. Polymers & Monomers 3. Biologically Important Compounds Carbohydrates Lipids Proteins Nucleic Acids 3 Biological Molecules Biological molecules consist primarily of -carbon bonded to carbon, or -carbon bonded to other molecules. Carbon can form up to 4 covalent bonds. Carbon may be bonded to functional groups with specific properties. Protons Neutrons Electrons 1. Carbon has 4 valence electrons 2. Each carbon atom four covalent bonds Carbon Chemistry
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Chemical Basis of Life
Outline: The Chemical Basis of Life
1. Chemistry of Carbon
2. Polymers & Monomers
3. Biologically Important Compounds CarbohydratesLipidsProteinsNucleic Acids
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Biological MoleculesBiological molecules consist primarily of
-carbon bonded to carbon, or-carbon bonded to other molecules.
Carbon can form up to 4 covalent bonds.
Carbon may be bonded to functional groups with specific properties.
ProtonsNeutronsElectrons
1. Carbon has 4 valence electrons
2. Each carbon atom four covalent bonds
Carbon Chemistry
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Electron PairCovalent Bond
Covalent Bonds in Carbon Carbon ChemistryMolecular Formula
CH4
C2H6
Carbon Chemistry
C4H10C4H10
C4H8 C4H8
Carbon Chemistry
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Carbon Chemistry
Structuralformula
Methane
H H
H
H H H
H
H
Ball-and-stickmodel
Space-fillingmodel
CC
The 4 single bonds of carbon point to the corners of a tetrahedron.
H H
HH
H H
Ethane Propane
HH
H H
H
H
H
H
H
H
Carbon skeletons vary in length.
H
H
H
H
H H
H H
H H
H H
H H
H H
H
H
H
H
H
H H H H
H
H
C
HH H
H H
H H
H
H
H
H H
HH
HH
H
H
H H
H
H
Butane IsobutaneSkeletons may be unbranched or branched.
1-Butene 2-ButeneSkeletons may have double bonds, which can vary in location.
CC C
CC
CH
CC
C
CC
C
Cyclohexane BenzeneSkeletons may be arranged in rings.
C C C C C
C C C C
C
C CC
CCC C CCCH H
Summary: Carbon Chemistry
4 Covalent Bonds
Variable Length
Unbranched or Branched
Single or Double Bonds
Rings
Functional Group
StructuralFormula
HS
P
O–
OO
HCH
H
OH
O
OHC
H
HN
CO
CH
HCHH
HOH
CHH
HC
O
OH
H
CH3
O HCCHO N
H
CHH
HHC
O
CHOH
H HS HC
H
CHOH
HC
OH
H HOC
HPO
CO
CO
HHC
H
O–
O–
O–
O–
FUNCTIONAL GROUPS Hydroxyl
Carbonyl
Carboxyl
Amino
Sulfhydryl
Phosphate
Methyl
HYDROXYL
Carboxyl
Melting Point (C)
C2H6O -114
C2H5O2 17
C2H6O 78
Boiling Point (C)
C2H5O2 118
Functional groups of male and female sex hormones
Male lion
Female lion
Estradiol
HO
OH
OH
OTestosterone
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Importance of Functional Groups
H
OH HOH
H OH
Dehydration reaction
H2O
Dehydration synthesis isPolymer Building
A B C D E
A B C D E
Unlinked monomer
Longer polymer
Short polymer
H
H2O
OH
H OHOH H
Hydrolysis
Hydrolysis is Polymer Breaking Classes of Biologically Important Compounds
CarbohydratesLipidsProteinsNucleic Acids
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Carbohydrates
Molecules • 1:2:1 ratio of carbon, hydrogen, oxygen
empirical formula: (CH2O)n
• examples: sugars, starch, glucose• C – H covalent bonds hold much energy• good energy storage molecules
Polysaccharides-long chains of sugars-used for energy storage-plants use starch; animals use glycogen-used for structural support-plants use cellulose; animals use chitin
End
Carbohydrates
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Classes of Biologically Important Compounds
CarbohydratesLipidsProteinsNucleic Acids
Properties
Non-polar molecules
Not Water soluble
Dissolve in nonpolar solvents
Lipids
1. Fatty acids
2. Triglycerides or neutral fats
3. Phospholipids
4. Steroids, prostaglandins and waxes
Types of Lipids
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Lipids
Fatty acids are long hydrocarbon chains which may be-saturated-unsaturated-polyunsaturated
Triglycerides (fats)-composed of 1 glycerol + 3 fatty acids
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Fatty Acid Structure
Hydrocarbon chain CarboxylGroup
Saturated & Unsaturated Fatty Acids
Cis & Trans Unsaturated Fatty Acids Structure of a Triglyceride
CC
C
OHOH
OH
H
HH
H
H
CC
C
Fatty acidFatty acid
Fatty acid
H
HH
H
H
Glycerol
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Triglycerides or Neutral Fats
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LipidsTriglycerides
excellent molecule for energy storagetwice as much energy as carbohydrates
animal fats usually saturated solid at room temperature
plant fats (oils) usually unsaturatedliquid at room temperature
Phospholipid Structure
Hydrophilic Polar Head
HydrophobicNonpolar Tails
Phospholipid bilayer Water
Membrane Structure
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Steroids
HydrocortisoneCholesterolDigitoxin
Steroids
Other Lipids
Waxes
Citronellol Taxol
Terpenes
Prostaglandins
Lipid Functions
1. Long term energy storageTriglycerides
1. ProtectionFat deposits around kidneysProstaglandin (thromboxane) induces clotting &
inflammation responseWaxes on leaf surface
2. Synthesis: hormonesCholesterol
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Classes of Biologically Important Compounds
Proteins
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Proteins
Enzyme catalysts
Transport
Motion
Defense
Support
Regulation -insulin
Calcium storage
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Proteins
Proteins are polymers of amino acids. Amino acids
-20 different amino acids-joined by dehydration synthesis-peptide bonds connect amino acids
Amino Acid Structure
Carboxyl Group
Amino Group
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Nonpolar Amino Acids
Amino Acid StructureAmino Acid Structure
Polar Uncharged
Polar Charged
Amino Acid Structure Amino Acid Structure
Aromatic
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Protein Synthesis Proteins Have Four Levels of Organization• Primary ..\
• Secondary
• Tertiary
• Quaternary
N N NH
H
H
H
H H
HC C C C C C N C C N CCC
O
OO
O H H
OH H
R
R
R R
R R
Primary Protein Structure
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Chain of amino acids
Secondary Protein Structure
Flexible e.g. wool
Tensile strength e.g. silk
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Tertiary Protein Structure
1. structural regions within a larger protein 2. folds into stable areas3. Modular units of 100 to 250 amino acids4. Domains are functional regions of a protein
