Transcript Ch_4_Carbon - Bartlett High School

Chapter 4
Carbon and the Molecular Diversity of
Life
Ch 4 Carbon and the Molecular Diversity of Life
1.
What is organic chemistry?
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Branch of chemistry that studies carbon compounds
Ch 4 Carbon and the Molecular Diversity of Life
1.
2.
What is organic chemistry?
What do you know about carbon?
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Atomic # = 6
Forms covalent bonds
Tetravalent – 4 valence electrons – forms 4 bonds
Tetravalence makes large, complex molecules possible.
Determines 3D shape of molecules
Compatible with other abundant elements
Hydrogen
Oxygen
Nitrogen
Carbon
(valence = 1)
(valence = 2)
(valence = 3)
(valence = 4)
H
O
N
C
Ch 4 Carbon and the Molecular Diversity of Life
1.
2.
3.
What is organic chemistry?
What do you know about carbon?
How does carbon contribute to molecular diversity?
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Carbon skeletons – covalent bonds that link C atoms together
& form the skeletal framework of organic molecules
Figure 4.5 Variations in carbon skeletons
H H
H H H
H C C H
H H
H C C C H
H H H
Ethane
Propane
H H H H
H
H C H
H
H
H C C C C H
H H H H
H C C C H
H H H
(a) Length
(b) Branching
Butane
(c) Double bonds
2-methylpropane
(commonly called isobutane)
H H H H
H H H H
H C C C C H
H H
H C C C C H
H
H
1-Butene
(d) Rings
H
H
H
H
H
H
H
C
C
C H
C
C H
H
C
H
H
Cyclohexane
2-Butene
H
H
C
H
C
C
H CC C H
H
Benzene
Ch 4 Carbon and the Molecular Diversity of Life
1.
2.
3.
4.
What is organic chemistry?
What do you know about carbon?
How does carbon contribute to molecular diversity?
What are hydrocarbons?
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Molecules consisting of only hydrogen & carbon
Fossil fuels
Some are biologically important (fats)
Hydrophobic (non-polar) – oil & water don’t mix
Ch 4 Carbon and the Molecular Diversity of Life
1.
2.
3.
4.
5.
What is organic chemistry?
What do you know about carbon?
How does carbon contribute to molecular diversity?
What are hydrocarbons?
What are isomers?
- cmpds w/ the same molecular formula but w/ different
structures & therefore, different properties
Figure 4.7 Three types of isomers
H
H C H
H H H
(a) Structural isomers
H C C C C C
H
H
H C C C
H H H
H H H H
X
(b) Geometric isomers
X
H
C C
X
C C
X
H
H
(c) Enantiomers
H C H
H
H
H H
H
CO2H
CO2H
C
C
H
H
NH2 NH2
CH3
L isomer
CH3
D isomer
H
Ch 4 Carbon and the Molecular Diversity of Life
1.
2.
3.
4.
5.
6.
What is organic chemistry?
What do you know about carbon?
How does carbon contribute to molecular diversity?
What are hydrocarbons?
What are isomers?
What are functional groups?
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Parts of molecules involved in chemical rxns
FUNCTIONAL
GROUP
HYDROXYL
CARBONYL
CARBOXYL
O
OH
(may be written HO
OH
)
OH), a hydrogen atom is
bonded to an oxygen atom,
which in turn is bonded to
the carbon skeleton of the
organic molecule. (Do not
confuse this functional
group with the hydroxide
ion, OH–.)
drawing electrons toward itself.
 Attracts water molecules,
helping dissolve organic
compounds such as sugars (see
Figure 5.3).
C
C
STRUCTURE In a hydroxyl group (—
FUNCTIONAL  Is polar as a result of the
PROPERTIES electronegative oxygen atom
O
The carbonyl group
( CO) consists of a
carbon atom joined to
an oxygen atom by a
double bond.
When an oxygen atom is doublebonded to a carbon atom that is
also bonded to a hydroxyl group,
the entire assembly of atoms is
called a carboxyl group (—
COOH).
 A ketone and an aldehyde
may be structural isomers
with different properties, as is
the case for acetone and
propanal.
 Has acidic properties because it is a
source of hydrogen ions.
The covalent bond between oxygen
and hydrogen is so polar that hydrogen
ions (H+) tend to dissociate reversibly;
for example,
H
H
C
H
Figure 4.10 Exploring some important
functional groups of organic compounds
H
O
H
C
OH
Acetic acid
C
H
O
+ H+
C
O
Acetate ion
AMINO
SULFHYDRYL
H
O
SH
N
(may be written HS )
H
FUNCTIONAL
GROUP
PHOSPHATE
O
P

O
OH
The amino group (—NH2)
consists of a nitrogen atom
bonded to two hydrogen atoms
and to the carbon skeleton.
The sulfhydryl group consists
of a sulfur atom bonded to an
atom of hydrogen; resembles a
hydroxyl group in shape.
In a phosphate group, a phosphorus
atom is bonded to four oxygen atoms;
one oxygen is bonded to the carbon
skeleton; two oxygens carry negative
charges; abbreviated P . The
phosphate group (—OPO32–) is an
ionized form of a phosphoric acid
group (—OPO3H2; note the two
hydrogens).
 Acts as a base; can pick
 Two sulfhydryl groups
 Makes the molecule of which
up a proton from the
surrounding solution:
can interact to help
stabilize protein
structure (see Figure
5.20).
it is a part an anion (negatively
charged ion). Can transfer
energy between organic
molecules.
H
N
H
+N
H
(nonionized)
H
H
(ionized)
 Ionized, with a charge of 1+, under cellular conditions.
STRUCTURE
FUNCTIONAL
PROPERTIES