Transcript PowerPoint 簡報 - Solon City Schools

Introduction to Bioorganic
Chemistry
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Chemistry of Biomolecules
A biomolecule is a chemical compound
that naturally occurs in living organisms.
Biomolecules consist primarily of carbon
and hydrogen, along with nitrogen, oxygen,
phosphorus and sulfur.
Other elements sometimes are
incorporated but are much less common.
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The Six Most Abundant
Elements of Life
THIS IS THE LEGAL CHNOPS!! 
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Valence
Each element has a characteristic valence that
determines the number of covalent bonds it can form.
A shared electron pair is called a covalent bond.
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Organic Molecules: Hydrocarbons
Hydrocarbons the simplest organic molecules, contain only
carbon and hydrogen atoms.
Name and
Comments
Molecular Structural
Formula
Formula
Ball-andStick Model
SpaceFilling
Model
H
(a) Methane
CH4
H C
H
H
(b) Ethane
H H
C2H6
H C C H
H H
(c) Ethene
(ethylene)
H
C2H4
H
C C
H
H
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Isomers
Organic molecules exist in three-dimensional
space, and the same set of atoms can be put
together in many recognizably different ways,
resulting in molecules called isomers.
1. Structural isomers: Variations in the position at which
different atoms are joined together.
2. Geometric isomers: Variations in the placement of
atoms around carbon atoms joined by double covalent
bonds.
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Isomers
H
(a) Structural isomers
H
(b) Geometric isomers
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
X
C
H
H
C
H
H
H
H
H
C
C
C
H
H
H
H
X
C
H
X
C
C
H
C
X
H
H
CO2H
CO2H
C
C
H
NH2
CH3
H
H
NH2
CH3
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Polarity (review)
As we already know…Many combinations of different
elements result in unequal electron
sharing, called polar bonding.
As a result, the electron distribution is asymmetric, or polar, and
the oxygen atom is said to be electronegative. This asymmetry
results in regions of slight negative and positive charge in different
regions of the molecule, denoted by the Greek symbol d, for
"partial" charge.
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The Functional Groups
The properties of different biological molecules depend on
certain characteristic groupings of atoms called functional
groups.
The names of the six
most important
functional groups are:
– Hydroxyl
– Carbonyl
–Aldehydes
– Ketones
– Carboxyl
– Amino
– Sulfhydryl
– Phosphate
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Hydroxyl Group
H
H
C
C
H
H
OH
H
OH
Ethanol
In a hydroxyl group (–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–).
Hydroxyl groups are not highly reactive, but they readily form
hydrogen bonds and contribute to making molecules soluble in
water.
Alcohols and sugars are "loaded" with hydroxyl groups.
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Carbonyl Group
O
C
Carbonyl group consists of a carbon atom joined to an oxygen
atom by a double bond (symbolized as C=O).
Like hydroxyl groups, carbonyl groups contribute to making
molecules water-soluble. All sugar molecules have one
carbonyl group, in addition to hydroxyl groups on the other
carbon atoms.
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Two Forms of Carbonyl Groups: Aldehydes
and Ketones
O
H
H
C
C
H
C
H
H
H
O
O
H
C
H
Propanal, an aldehyde
C
C
H
H
C
H
H
Acetone, a ketone
Aldehyde groups, where the C=O group is at the end of an
organic molecule. A hydrogen atom is also located on the same
carbon atom.
Keto groups, where the C=O group is located within an
organic molecule. All sugars have either a keto or an aldehyde
group.
An aldehyde and a ketone may be structural isomers with
different properties, as is the case for acetone and propanal.
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Carboxyl Group (Acids)
H
O
C
H
C
OH
H
H
O
H
C
OH
Acetic Acid
C
H
O
+ H+
C
O
Acetate
The carboxyl group (symbolized as COOH) has both a
carbonyl and a hydroxyl group attached to the same carbon
atom, resulting in new properties.
Carboxyl groups are weak acids, dissociating partially to
release hydrogen ions.
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Amino Group
H
H
N
H
+N
H
N
H
H
H
nonionized
ionized
The amino group (–NH2) consists of a nitrogen atom bonded
to two hydrogen atoms and to the carbon skeleton.
Found in amino acids
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Sulfhydryl Group
SH
The sulfhydryl group (–SH) consists of a sulfur atom bonded
to an atom of hydrogen; resembles a hydroxyl group in shape.
Two sulfhydryl groups can interact to help stabilize protein
structure called disulfide bond (symbolized as -S-S-).
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Phosphate Group (Acids)
O
O P OH
OH
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).
Makes the molecule of which is a part an anion (negatively
charged ion).
Can transfer energy between organic molecules (e.g., ATP).
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ATP
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The Functional Groups
Functional groups are
the chemically
reactive groups of
atoms within an
organic molecule.
Many are polar
Give organic
molecules distinctive
chemical properties.
Most Important in the
Chemistry of Life
Estradiol
OH
CH3
HO
Female lion
OH
CH3
CH3
O
Testosterone
Male lion
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Putting things
together…let’s make some
MACROMOLECULES
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Monomers & Polymers:
• monomers
• smaller building
blocks of the polymers
(macromolecules)
• amino acids build
proteins:
•Nucleotides build nucleic
acids:
• monosaccharides build
carbohydrates:
• fatty acids & glycerol
build lipids:
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Synthesis = dehydration synthesis
Removal of WATER OH + H forms water,
H2O
Leaves bonding sites that join
monosaccharide units.
19 Aug. 2009
Chemistry.ppt
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Disassembly = hydrolysis
Break bond between monosaccharide
units (“lysis” means “to break”)
Add WATER OH + H to fill bonding sites.
19 Aug. 2009
Chemistry.ppt
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Putting together / Taking apart macromolecules:
macromolecules: monomers <--> polymers
Dehydration Synthesis
Hydrolysis
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fig 4.3
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We will be studying four organic
macromolecules…
Carboyhdrates
Lipids
Proteins
Nucleic Acids
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