Download Ch 4 Carbon teacher

Chemistry of Carbon
Chapter 4
Building Blocks of Life
AP Biology
Why study Carbon?
 All of life is built on carbon
 Cells
~72% H2O
 ~25% carbon compounds

 carbohydrates
 lipids
 proteins
 nucleic acids

~3% salts

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Na, Cl, K…
Organic chemistry is the study of carbon
compounds
 Organic chemistry is the study of carbon
compounds
 Organic compounds- compounds containing Carbon,
and usually hydrogen
 Ex. CH4- Methane
 Synthesized abiotically in early Earth
 Exception- CO2 (inorganic)
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Macromolecules
 Smaller organic molecules join together to
form larger molecules

Macromolecules
4 major classes of macromolecules:
carbohydrates
lipids
proteins
nucleic acids
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Carbons forms diverse molecules by bonding
to four other Atoms
 4 valence electrons- valence of 4

Bonding partners: C,H, O, N
 Forms covalent bonds


May be single or double
Tetravalent
 Tetra= 4
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Tetrahedral
 Forms tetrahydrons- Occurs when Carbon forms 4
single bonds with other atoms (arrangement of orbitals)
known as a tetrahedral shape
 Ex. Methane (CH4)
 Ethane (C2H6)
 Ethene (ethylene)- 2 Carbon atoms joined by a double
bond
 Forms a flat molecule- Carbons are in same plane
 Shape of molecule determines function
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Properties of Carbon
 C atoms are versatile building blocks
Bonding properties
 4 stable covalent bonds
Accounts for diversity of biological molecules


H
H
C
H
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H
Studies of Organic Compounds
 Vitalism- belief in life outside physical and chemical
laws
 No longer accepted
 Freidrich Wohler- 1828 ; German chemist attempted
to make an “inorganic” salt (Ammonia cyanate) by
mixing ammonia ions (NH4+) and cyanate ions
(CNO-)
 Made urea- organic compound found in urine
 Hermann Kolbe- Wohler’s student made acetic acid
from inorganic compounds
 Abiotic synthesis of organic compounds from early
life’s elements- Stanley Miller’s experiment (1953)
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Carbon Skeleton Variation

Length
 Ethane, Propane

Branching- straight or branched
 Butane

Double Bonds
 Butene

Rings
 Benzene
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Hydrocarbons (HC)





Organic compounds consisting of only C & H
 Ex. Ethane, Butene, Benzene, Methane
Stable
Not prevalent in organisms
 Except lipids- hydrocarbon tails
Gas at room temp
Prevalent in fossil fuels
 Ex. Petroleum, gasoline
methane
(simplest HC)
Hydrophobic (Non polar)
 Store large amounts of energy
 Ex. Fats in mammals stored in Adipose tissue
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
Complex molecules assembled like TinkerToys
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Isomers
 Molecules with same molecular formula but
different structures (shapes)
different chemical properties
 different biological functions

6 carbons
6 carbons
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6 carbons
3 Types of Isomers
 Structural- different covalent partners
 May be differ in location of double bonds
 Geometric- same covalent partners, different spatial

arrangement
 Difference in shape- affects biological activity
Enantiomers- Mirror images of each other
 Middle Carbon- Asymmetric Carbon
 Ex. Ball & stick models
 Important for pharmaceuticals
 Asthma and pain medications
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3 Types of isomers
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Form affects function
 Structural differences create important
functional significance

amino acid alanine
 L-alanine used in proteins
 but not D-alanine

medicines
 L-version active
 but not D-version

sometimes with
tragic results…
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stereoisomers
Figure 4.7 The pharmacological importance of enantiomers
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Form affects function
 Thalidomide
prescribed to pregnant women in 50s & 60s
 reduced morning sickness, but…
 stereoisomer caused severe birth defects

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Functional groups
 Parts of organic molecules that are involved
in chemical reactions

give organic molecules distinctive properties
hydroxyl
 carbonyl
 carboxyl

amino
 sulfhydryl
 phosphate

 Affect reactivity
makes hydrocarbons hydrophilic
 increase solubility in water

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Viva la difference!
 Basic structure of male & female
hormones is identical



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identical carbon skeleton
attachment of different functional groups
interact with different targets in the body
 different effects
Carbonyl
 C=O

O double bonded to C
 if C=O at end molecule = aldehyde
 if C=O in middle of molecule = ketone
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Figure 5.3 The structure and classification of some monosaccharides
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Hydroxyl
 –OH
organic compounds with OH = alcohols
 names typically end in -ol

 Ethanol

Hydroxyl
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Amino
 -NH2

N attached to 2 H
 compounds with NH2 = amines
 amino acids
 NH2 acts as base
 ammonia picks up H+ from solution
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Sulfhydryl
 –SH

S bonded to H
 compounds with SH = thiols
 SH groups stabilize the structure of proteins
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Phosphate
 –PO4

P bound to 4 O
 connects to C through an O
 lots of O = lots of negative charge
 highly reactive
 transfers energy between organic molecules
 ATP, GTP, etc.
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Carboxyl
 –COOH

C double bonded to O & single bonded
to OH group
 compounds with COOH = acids
 fatty acids
 amino acids
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ATP

Adenosine Triphosphate (ATP)- cells main
energy souce
 Organic compound attached to 3 Phosphate groups

Adenosine Dihosphate (ADP) A Phosphate may split off in H2O
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Polymers
 Long molecules built by linking repeating
building blocks in a chain

monomers
 building blocks
 repeated small units

H 2O
covalent bonds
HO
H
HO
H
Dehydration synthesis
HO
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H
Building & Breaking Polymers
Dehydration synthesis
Condensation reaction
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Building polymers from
monomer
Synthesis= building
Monomer+ Monomer
Polymer
Dehydration= water loss
Hydrolysis Breaking down polymers into
monomers
Hydro= water
Lysis= Break down
Polymer
Monomers
How to build a polymer
 Synthesis

You gotta
be open to
“bonding!
joins monomers by “taking” H2O out
 one monomer donates OH–
 other monomer donates H+
 together these form H2O

H 2O
requires energy & enzymes
HO
H
Dehydration synthesis
HO
H
enzyme
Condensation reaction
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HO
H
Dehydration Synthesis
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How to break down a polymer
Breaking up
is hard to do!
 Digestion

use H2O to breakdown polymers
 reverse of dehydration synthesis
 cleave off one monomer at a time
 H2O is split into H+ and OH–
 H+ & OH– attach to ends
requires enzymes
HO
 releases energy
H2O

enzyme
H
Hydrolysis
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Digestion
HO
H
HO
H
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35
Any Questions??
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2007-2008
Vitalism
 "Vitalism—the insistence that there is some big,

mysterious extra ingredient in all living things—turns
out to have been not a deep insight but a failure of
imagination." --Daniel Dennett
Vitalism is the metaphysical doctrine that living
organisms possess a non-physical inner force or
energy that gives them the property of life.
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 Vitalists believe that the laws of physics and chemistry


alone cannot explain life functions and processes.
Vitalism is opposed to mechanistic materialism and its
thesis that life emerges from a complex combination of
organic matter.
The vitalistic principle goes by many names: chi or qi
(China) prana (India and therapeutic touch), ki (Japan);
American advocates much prefer the term energy. Many
kinds of alternative therapies or energy medicines are
based upon a belief that health is determined by the flow
of this alleged energy.
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 For examples, see acupuncture,
Ayurvedic medicine, therapeutic touch,
reiki, and qigong.
 Energy medicine is a placebo, leading
many advocates to mistake the effects of
classical conditioning, expectation of
relief that leads to reduction of anxiety
and stress, and beliefs about the
effectiveness of the medicine as effects
of mythical energy.
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