Post on 21-Dec-2015
The Chemical Building Blocks of Life
Outline: The Chemical Building Blocks of Life
1. Chemistry of Carbon
2. Polymers & Monomers
3. Biologically Important Compounds Carbohydrates Lipids Proteins Nucleic Acids
3
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
Electron PairCovalent Bond
Covalent Bonds in Carbon
Carbon ChemistryMolecular Formula
CH4
C2H6
Carbon Chemistry
C4H10C4H10
C4H8 C4H8
Carbon Chemistry
Carbon Chemistry
Structuralformula
Methane
H H
H
H H H
H
H
Ball-and-stickmodel
Space-fillingmodel
C
C
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
H
H
HH
H
H
H H
H
H
Butane Isobutane
Skeletons may be unbranched or branched.
1-Butene 2-Butene
Skeletons may have double bonds, which can vary in location.
CC C
C
CC
H
CC
C
CC
C
Cyclohexane Benzene
Skeletons 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–
O
O
HC
H
H
OH
O
OHC
H
HN
CO
C
H
H
CH
H
H
OH
CH
H
HC
O
OH
H
CH3
OH
CCHO NH
CH
H
HHC
O
CHOH
H HS HC
H
CH
OH
HC
OH
H HOC
H
P
O
C
O
C
O
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
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
17
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
Structure of Monosaccharides
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H H
H
H
H
HO
H
H
H
C
O
HO
OH
OH
OH
OH OH
OH
OH
C O
OH
Glucose Fructose
C6H12O6
CarbonylGroup
HydroxylGroups
19
Carbohydrates
C6H12O6
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H H HHH
OH OH
OHO
OH H
OHO
OH
HOO
OH
OH H
HH
HO
H H
HH
OH
H
OH
OH
OH
H
H
HO
CH2OH
HH
H
OH
O
GalactoseFructoseGlucose
RiboseGlyceraldehyde
3-carbonsugar
5-carbon sugars
6-carbon sugars
Deoxyribose
HH
H
H
H
H
OH
OH
OC
C
C4
5
1
3 2
4
4
4
4
5
5
55
666
1
1
1
1
3
3
2
233
2
2
1
3
2
CH2OH CH2OH
CH2OH CH2OH
CH2OH
H
Monosaccharide Structure
21
Carbohydrates - Disaccharides
-2 monosaccharides linked together by dehydration synthesis
-used for sugar transport or energy storage
-examples: sucrose, lactose, maltose
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CH2OH
Starch: chain of -glucose subunits
HO
OH
OH HH
H H
H
O O O O O
HOOH
OH HHH
H
H
H
O
Cellulose: chain of - glucose subunits
OH
OH HHH
H
H OH
OH HH
HH
H OH
OH HH
H H
H OH
OH HHH H
H
O
Plantcell wall
HH
H
OH
OHH
OH
OHO O O
O O
14
4 1
form of glucose
form of glucose
4 1
14
H OH
H
O HOH
H H
OO
OH
O
HOH
HOHH
H O
CH2OH CH2OH CH2OH CH2OH
CH2OHCH2OH
CH2OH
CH2OH
CH2OH
OHHHH
Cellulose
Starch
Polysaccharides – Complex Carbohydrates
Glycogen
23
Carbohydrates
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
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
26
Lipids
Fatty acids are long hydrocarbon chains which may be-saturated -unsaturated -polyunsaturated
Triglycerides (fats)-composed of 1 glycerol + 3 fatty acids
Fatty Acid Structure
Hydrocarbon chain CarboxylGroup
Saturated & Unsaturated Fatty Acids
Cis & Trans Unsaturated Fatty Acids
Structure of a Triglyceride
C
C
C
OH
OH
OH
H
H
H
H
H
C
C
C
Fatty acid
Fatty acid
Fatty acid
H
H
H
H
H
Glycerol
Triglycerides or Neutral Fats
32
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 HeadHydrophobicNonpolar Tails
Phospholipid bilayer Water
Membrane Structure
Steroids
HydrocortisoneCholesterol
Digitoxin
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
Classes of Biologically Important Compounds
Proteins
40
Proteins
Enzyme catalysts
Transport
Motion
Defense
Support
Regulation - insulin
Calcium storage
41
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
Nonpolar Amino Acids
Amino Acid Structure
Amino Acid Structure
Polar Uncharged
Polar Charged
Amino Acid Structure
Amino Acid Structure
Aromatic
Protein Synthesis
Proteins Have Four Levels of Organization• Primary ..\
• Secondary• Tertiary• Quaternary
N N N
H
H
H
H
H H
H
C 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
1
Chain of amino acids
Secondary Protein Structure
Flexible e.g. wool
Tensile strength e.g. silk
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
Tertiary Structure: Domains
1. Hydrogen Bond
2. Disulfide bridge
3. Ionic bond
4. Van der Waals attraction
5. Hydrophobic Exclusion
Bonds Stabilize Protein Structure
54
ProteinsDenaturation is a change in the shape of a
protein, usually causing loss of function.
-may involve complete unfolding
-caused by changes in the protein’s environment
-pH
-temperature
-salt concentration
Normal (Good) PrPC43% -helix
Prion (Bad) PrPSc30% -helix43% -sheet
Normal Protein Folding is Critical to Function
Mistake in tertiary protein structure
Creutzfeldt Jacob Disease
Chronic Wasting Disease
Bovine Spongiform encephalopathy(Mad Cow Disease)
Fig. 3.8h(TE Art)
Quaternary ProteinStructure
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58
Protein Structure
Primary
Secondary
Tertiary Quaternary
Secondary
Nucleic Acids
Nucleic Acid = polymer of nucleotides
Types of Nucleic Acids Deoxyribonucleic Acid = DNA
Genetic material
Ribonucleic Acid = RNA Protein synthesis
Fig. 3.14(TE Art)
Phosphate group
Sugar
Nitrogenous base
N
N
O
P CH2
O
–O
O–
OH ROH in RNA
H in DNA
O
N
NH2
N
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A Nucleotide is a monomer of a nucleic acid
Nitrogen Bases of Nucleic Acids
Nucleic Acid Structure
Fig. 3.16(TE Art)
P
P
P
P
P
P
P
P
C
C
G
G
A
A
T
T
P
OC G
5’ end
3’ end
OH
P
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DNA StructureDouble Helix
Paired Nitrogen Bases
Hydrogen bonds
Sugar-phosphate "backbone"
Nucleotide
RNA Structure
Ribose (sugar)
NitrogenousBases
G
G
C
A
A
U
U
P
P
PP
P
P
P
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Phosphate
Triphosphate group
5-carbon sugar
Nitrogenous base(adenine)
OP CH2
O
O
O–
P
O
O
O–
P
O
–O
O–
OH OH
OO
NH2
N
N
N
N
Adenosine Triphosphate
ATP