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General Chemistry Review
Part I
General Chemistry: Carbon Atom
1. Atomic Theory
2. Covalent Bonding
3. Chemical Formulas
General Chemistry of Carbon
Carbon is a non-metal chemical
element.
A covalent bond is a chemical bond
that involves the sharing of electron
pairs between atoms.
General Chemistry of Carbon
Carbon atomic number = 6 Protons6 Electrons6 Neutrons
Group IV Four valence electrons
Atomic Theory of Carbon
Ground state electronic configuration of
carbon is:
1s22s22p2
[He] 2s22p21S2
2S2
2P2
Nucleus
Electronic Configuration1
2
3
4
5
6
7
C
Atomic Theory of Carbon
Carbon atom ground state configuration:1s2 2s2 2Px
1 2Py1 2Pz
0
Covalent Bonding
Carbon can covalently bond with other elements: Hydrogen
Oxygen
Nitrogen
Sulfur
Halogens
Covalent Bonding
Carbon only forms single, double or triple bonds with other carbon atoms
Covalent Bonding
Carbon only forms single bonds with hydrogen and/or halogens atoms
Covalent Bonding
Carbon may form single bonds with nitrogen, oxygen and sulfur
Covalent Bonding
Carbon may also form double bonds with nitrogen, oxygen and sulfur
Covalent Bonding
Carbon may also form triple bonds with nitrogen, sulfur and oxygen
Chemical Formulas
Three classes are:
1. Molecular
2. Structural
3. Condensed
Molecular Formulas
Show:
The types of atoms present
The numbers of each atom present in a
molecule
Molecular Formulas
For example, glucose
Symbols for carbon, hydrogen, and
oxygen are C, H, and O respectively
Molecular formula for glucose is C6H12O6
Structural Formula s
Show arrangement of atoms:
How atoms are bonded,
In which order they are bonded
Whether single, double or triple bonds are
used
Structural Formulas: Examples
Condensed Formulas
Show:
Groups of atoms in a molecule
The sequential relationships of these group of
atoms to each other with or without showing
covalent bonds
Condensed Formulas: Examples
Condensed Formulas: Examples
Organic Chemistry Review
Part II
Organic Chemistry: Carbon Atom
1. Structural Classifications
2. Atomic Theory
3. Dipoles &
Resonance
4. Isomers
5. Functional Groups
6. Organic Reactions
Organic Chemistry
The chemistry of compounds which contain carbon.
Carbon forms more compounds than any other element, except hydrogen.
Organic Chemistry Major Concepts
1. Structural Classifications
2. Hybridization
3. Charges of Organic Molecules
4. Dipoles & Dipolar Resonance
5. Isomers
6. Functional Groups
7. Organic Reactions
Structural Classification of Carbon Atoms
Three main classifications are:
1. Primary Carbons
2. Secondary Carbons
3. Tertiary Carbons
4. Quaternary Carbons
Primary Carbons
Denoted as 1° carbons.
Also called terminal or end carbon atoms.
Found at the ends of a straight chains or the
branches.
Covalently bonded to one carbon atom.
CH3 – CH2 – CH3
Secondary Carbons
Denoted as 2° carbons.
Covalently bonded to two other carbon
atoms.
CH3 – CH2 – CH3
Tertiary Carbons
Denoted as 3° carbons.
Covalently bonded to three other carbon
atoms. CH3 – CH – CH3
| CH3
Quaternary Carbons
Denoted as 4° carbons.
Covalently bonded to four other carbon
atoms. CH3 |
CH3 – C – CH3
| CH3
Definitions
Valence Bond Theory: Electrons in a covalent bond reside in a region
in which there is overlap of individual atomic orbitals.
For example, the covalent bond in molecular methane (CH4) requires the overlap of valence electrons:
Definitions
Types of valence bond theory overlap:
Definitions
Valence Shell Electron Pair Repulsion (VSEPR) Electron pairs arrange themselves around an
atom in order to minimize repulsions between pairs.
Carbon has a valence of four and must have a tetrahedral geometry.
In methane, each carbon atom must have a bond angle of 109.5⁰. This is the largest bond angle that can be attained between all four bonding pairs at once.
Definitions
Hybridization: Atomic orbitals modify themselves to meet
VESPR geometry and valence bond theory. Three types of hybridization for carbon:
Hybridization: Valence Bond Theory
Hybridization: VSEPR Geometry
Hybridizations
Hybridizations
In sp3 hybridization, an electron is promoted from a 2s orbital into a p orbital.
The 2s orbital and three 2p orbitals form four hybrid orbitals (sp3).
Ground state: 1s2 2s2 2Px1 2Py
1 2Pz0
Excited state: 1s2 2s1 2Px1 2Py
1 2Pz1
Hybridizations
The overlap of each hybrid orbital with a hydrogen atom results in a sigma bond ( σ bond).
Only one σ bond can exist between two atoms.
Hybridizations
sp3 hybridization of methane:
Hybridizations
sp3 hybridization of ethane:
Hybridizations
In sp2 hybridization, the 2s orbital and two of the 2p orbitals form three hybrid orbitals (sp2).
The Pz orbital of each carbon atom remains unhybridized.
These unhybridized Pz orbitals overlap with one another to form a π-bond.
Hybridizations
sp2 hybridization of ethene:
Hybridizations
sp2 hybridization and bond rotation:
Hybridizations
In sp hybridization, the 2s orbital and one 2p orbital form two hybrid orbitals (sp).
The triple bond is actually one σ bond and two π bonds.
Hybridizations
sp hybridization of ethyne:
No free rotation
Charges in Organic Molecules
Definitions
Dipole: The measure of net molecular polarity. Formula: the magnitude of the charge Q times
the distance r between the charges.
μ = Q × r The larger the difference in electronegativities
of the bonded atoms, the larger the dipole moment.
Definitions
Resonance: Part of the Valence Bond Theory Describes the delocalization of electrons within
molecules. Used when Lewis structures for a single
molecule cannot describe the actual bond lengths between atoms.
Structures are not isomers of the target molecule, since they only differ by the position of delocalized electrons.
Definitions
Resonance Hybrid: The net sum of valid resonance structures. Several structures represent the
overall delocalization of electrons within the molecule.
A molecule that has several resonance structures is more stable than one with fewer.
Definitions
Hyperconjugation: The interaction of the electrons in a sigma
bond (usually C–H or C–C) with an adjacent empty (or partially filled) non-bonding p-orbital, antibonding π orbital, or filled π orbital.
Only electrons in bonds that are β to the positively charged carbon can stabilize a carbocation by hyperconjugation.
Carbon Atom Dipoles
Carbon- Halogen Bonds
Carbon Atom Dipoles
C-O, C-S and C-N Covalent Bonds:
δ+
δ+ δ-
δ-
Dipolar Resonance
Dipolar Resonance
Dipolar Resonance
Dipolar Resonance
Hyperconjugation
A.K.A "no bond resonance". The delocalization of σ-electrons or lone pair of
electrons into adjacent π-orbital or p-orbital. Overlapping of σ-bonding orbital or the orbital
containing a lone pair with adjacent π-orbital or p-orbital.
An α- carbon next to the π bond, carbocation or free radical should be sp3 hybridized with at least one hydrogen atom bonded to it.
Hyperconjugation
Other hydrogens on the methyl group also participate due to free rotation of the C-C bond.
There is NO bond between an α-carbon and one of the hydrogen atoms.
The hydrogen atom is completely detached from the structure.
The C-C bond acquires some double bond character and C=C acquires some single bond character.
Hyperconjugation
Hyperconjugation: Examples
Hyperconjugation: Examples
Hyperconjugation: Examples
Isomers
Compounds that have:
The same molecular formula.
Similar or different types of structural
formulas.
Different arrangement of atoms.
Isomers:
Two main classes are:
1. Structural or constitutional
2. Stereoisomers
Structural Isomers
Also known as constitutional isomers
Stereoisomers
a. Configurational
Geometric or Diastereomers
Optical or Enantiomers
b. Conformational or Rotamers
Diastereomers
Geometric Isomers: Examples
Geometric Isomers: Examples
Optical Isomers
Definitions
Chiral Molecules - when a molecule and its mirror image cannot completely overlap. They are non-superimposable mirror images of one another.
Dextrorotatory (R, +) - a compound whose solution rotates the plane of polarized light to the right (when looking toward the source of light).
Definitions
Levorotatory (S, -) - a compound whose solution rotates the plane of polarized light to the left (when looking toward the source of light).
Racemic Mixture - a mixture of equal amounts of optical isomers. Because the two isomers rotate the plane of polarized light by the same angle in opposite directions, they cancel each other out and have no net effect.
Determining L (S, -) or D (R, +) configuration
1. Rank the four substituents according to the
atomic numbers of the atoms bonded
directly to the double bonded carbons,
from highest (1) to lowest (4).
Determining L (S, -) or D (R, +) configuration
2. If two substituents have the same ranking: Look at the next atoms in their substituent
chains. List the atoms that are two bonds away
from the chiral center according to their atomic number, from highest to lowest.
Assign the lower number to the substituent that has the atom with the higher atomic number.
Determining L (S) or D (R) configuration If it is still the same atom for both
substituents, continue down the list until a difference is found and assign a ranking in the same manner.
3. If a substituent has a double or triple bonds in its chain, it is counted as two or three bonds to the same atom.
Determining L (S, -) or D (R, +) configuration
4. Determine whether the ranking defines a
clockwise or counterclockwise direction.
If clockwise, the projection is an R
configuration.
If counterclockwise, it is an S configuration.
Determining L (S, -) or D (R, +) configuration
L (S, -) Configuration
A common optical isomer for amino acids in Biochemistry
Optical Isomers: Examples
Summary of Isomers
Summary of Isomers
Conformational Isomers
Also known as Rotamers Stereoisomers that can be interconverted
by the rotation of atoms about a σ-bond.
Conformational Isomers
Rotamers: Examples
Functional Groups
1. Hydrocarbons
2. Derivatives of Hydrocarbons
Functional Groups
Organic molecules may have functional
groups attached.
A functional group is a group of atoms of a
particular arrangement that gives the entire
molecule certain chemical characteristics.
Functional groups are named according to
the composition of the group.
Functional Groups
Organic chemists use the letter "R" to indicate
an organic molecule.
The "R" can be any organic molecule.
Hydrocarbons
The simplest organic compounds.
Contain only carbon and hydrogen,
Can be straight-chain, branched chain, or cyclic
molecules.
Carbon tends to form four bonds in a tetrahedral
geometry.
Hydrocarbons
Two classifications:
1. Aliphatics
2. Aromatics
Aliphatic - hydrocarbons which do not contain an
aromatic ring.
Hydrocarbons
Aromatic - Aromatic hydrocarbons contain a set
of covalently bound atoms with specific
characteristics:
A delocalized conjugated π system, with the
common arrangement of alternating single and
double bonds
Aliphatics
1. Alkanes
2. Cycloalkanes
3. Alkenes
4. Alkynes
Alkanes
IUPAC ending is …ane
Alkanes
Saturated hydrocarbons. Are hydrocarbons which contain only single
bonds. All alkanes are insoluble in water, but dissolve
in organic solvents. Density, viscosity, melting point & boiling
points increase as the molecular weight/size of the hydrocarbon increases.
Alkanes
Contain single covalent bonds.
Have the same structural formula:
Cn H2n+2
All carbons have single bonds therefore the molecular geometry is tetrahedral.
Alkanes
The names of alkanes start with the name of the alkane but end with the suffix –ane.
Alkanes
Each atom in an alkane uses all its 4 valence electrons in forming single bonds with other atoms.
Alkyl groups may be used as substituents for hydrogens.
Alkanes
Alkyl groups form the branches of straight chain hydrocarbons.
Can have more than one alkyl group for hydrogens. For multiple substituents of the same type, use the
following prefixes: di- tri- tetra- penta- hexa-
Alkanes
Alkanes
Other functional groups can be used as substituents.
More than one substituent requires a prefix. Any hydrogen can be substituted by:
1. Halogens
2. Alcohols
3. Amines
4. Nitriles
5. Thiols
6. Aldehydes
7. Ketones
Alkanes
Any carbon can be substituted by: Carboxylic Acids Esters Amides Thioesters
Addition of other atoms: Ethers Thioethers Disulfides
Cycloalkanes
the prefix cyclo- and the ending …ane
Cycloalkanes
Saturated hydrocarbons. Form one or more rings fused together. A single carbon in a ring may have two hydrogen
atoms. Are insoluble in water, but dissolve in organic
solvents. Have higher boiling points, melting points, and
densities than alkanes.
Cycloalkanes
All have the same general formula:
CnH2n
The carbon atoms in cycloalkanes are sp3
hybridized.
Each atom in a cycloalkane uses all its 4 valence
electrons in forming covalent bonds with other
atoms.
Cycloalkanes
Can have more than one alkyl group to make straight chains.
For multiple alkyl groups of the same type, use prefixes.
Cycloalkanes
Many functional groups can be used as substituents. More than one substituent requires a prefix. Any hydrogen or carbon atom can be substituted by:
Cycloalkanes
The names follow those of the alkanes with the prefix cyclo- .
Cycloalkanes
Cycloalkanes
Cycloalkanes
Alkenes
IUPAC ending is …ene
Alkenes
Also known as olefins. Are unsaturated hydrocarbons and are generally
very reactive. Are insoluble in water, but dissolve in organic
solvents. Ethene, propene and butene are gases at room
temperature. The remaining are liquids. Boiling points increases with molecular mass
(chain length). The higher the molecular mass, the higher the boiling point.
Alkenes
Are hydrocarbons which contain one or more double bonds.
Double bonds are:
Have the same structural formula:
CnH2n
Alkenes
The main centers are the carbons of the double bond.
The geometry of each carbon in the center is trigonal planar.
This portion of the molecule is flat, with bond angles of 120 degrees.
Alkenes
All the alkenes with 4 or more carbon atoms in them show structural isomerism.
Alkenes
The carbon-carbon double bond does not rotate.
Substituents groups on the molecule are locked on either one side of the molecule or opposite each other.
Alkenes
The names of alkenes start with the name of the alkane but end with the suffix –ene.
For alkenes above propene, the position of the double bond must be specified in the name.
Alkenes
Can have more than one alkyl group to form branches.
For more than one alkyl group, use prefixes.
Alkenes
Many functional groups can be used as substituents. More than one substituent requires a prefix. Any hydrogen or carbon atom can be substituted by:
Alkenes
For multiple double bonds, use the following prefixes: di- tri- tetra- penta- hexa-
Alkenes
A diene is a hydrocarbon chain that has two double bonds that may or may not be adjacent to each other.
Alkenes: Examples
Alkenes: Examples
Alkynes
IUPAC ending is …yne
Alkynes
Also known as acetylenes. Are unsaturated hydrocarbons and are
generally very reactive. Are insoluble in water; but quite soluble in
organic solvents of low polarity (e.g. ligroin, ether, benzene, carbon tetrachloride, etc.).
Alkynes of four or fewer carbon atoms are gases. The rest are liquids.
Their boiling points increase with increasing number of carbons.
Alkynes
Are hydrocarbons which contain one or more triple bonds.
Triple bonds are:
Have the same structural formula:
CnH2n-2
Alkynes
The main centers are the carbons of the triple bond.
The geometry of the center is linear. This portion of the molecule is linear, with
bond angles of 180 degrees.
Alkynes
All the alkynes with 4 or more carbon atoms in them show structural isomerism.
Alkynes
The names of alkynes start with the name of the alkane but end with the suffix –yne.
For alkynes above propyne, the position of the triple bond must be specified in the name.
Alkynes
Many functional groups can be used as substituents. Only one substituent is allowed. Any hydrogen or carbon atom can be substituted by:
Alkynes
For multiple double bonds, use the following prefixes: di- tri- tetra- penta- hexa-
Alkynes: Examples
Aromatics
Structures that meet Huckel’s Rule
Aromatics
Coplanar structures, with all the contributing atoms in the same plane.
Are arranged in one or more rings. Benzene rings are not a common motif.
The three general requirements for a compound to be aromatic are: The compound must be cyclic. Each element within the ring must have a p-orbital that
is perpendicular to the ring, hence the molecule is planar.
The compound must follow Hückel's Rule.
Aromatics
The number of π delocalized electrons must follow Hückel's Rule.
number of π electrons = 4n + 2
where n = 0, 1, 2, 3, and so on
The number of π delocalized electrons is an even number, but not a multiple of 4 to be an aromatic compound.
Aromatics
The most common examples of aromatic hydrocarbons are organic compounds, which contain one or more benzene rings.
Benzene
Aromatics
Benzene follows Huckel’s Rule:
Aromatics
Each atom in benzene uses all its 4 valence
electrons in forming covalent bonds with other
atoms.
Other functional groups can be used as
substituents.
More than one substituent requires a prefix.
Aromatics
Any hydrogen or carbon atom can be substituted by:
Aromatics
When two substituents are attached to the benzene ring: Ortho, meta, or para can be used to indicate
where the two substituents are on the benzene ring.
Three classifications:ortho- (o-): position 1, 2- meta- (m): posotion 1, 3- para- (p): position 1, 4-
Aromatics
Aromatics: Examples
o-dihydroxybenzene, m-dihydroxybenzene, p-dihydroxybenzene
Aromatics: Examples
Aromatics: Examples
Aromatics: Examples
Aromatics: Examples
Summary of Hydrocarbon
Summary of Hydrocarbon
Summary of Hydrocarbon
Derivatives of Hydrocarbons
Are formed when there is a substitution of a functional group at one or more carbon
atoms.
Derivatives of Hydrocarbons
1. Prefixes
2. Haloalkanes
3. Alcohols
4. Ethers
5. Amines
6. Nitriles
7. Thiols
8. Thioethers
9. Disulfides
10. Aldehydes
11. Ketones
12. Carboxylic Acids
13. Esters
14. Amides
15. Thioesters
Prefixes
For multiple substituents of the same
type, use the following prefixes:
di-
tri-
tetra-
penta-
hexa-
Haloalkanes The alkyl halides have the general form
where the R in the general form is typically an alkyl group with a halogen replacing one of the hydrogens.
X is written as: F = fluoro Cl = chloro Br = bromo I = iodo
Haloalkanes
Classify according to the number of carbons
bonded directly to the alkyl halide.
Haloalkanes
There can be multiple substitutions of halogens
for hydrogens, and also variations where
alkenes, alkynes or aromatics are involved.
C – O Bonds Organic Compounds
1. Alcohols
2. Ethers
Alcohols
IUPAC ending is …ol
Alcohols
Are organic compounds containing a hydroxyl group, -OH, substituted for a hydrogen atom.
The center of the alcohol functional group is the oxygen.
Have two lone pairs of electrons on the oxygen. This forces the molecular geometry on the
alcohol oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.
Alcohols
Are organic compounds containing a hydroxyl group, -OH, substituted for a hydrogen atom.
The names of alcohols start with the name of the alkane but end with the suffix –ol.
Can have more than one hydroxyl group for hydrogens, and also variations where alkenes, alkynes or aromatics are involved.
Use a prefix for multiple hydroxyl groups.
Alcohols
Are classified according to the number of carbon atoms attached directly to the carbon containing the hydroxyl group.
Ethers
… “oxy”….IUPAC ending ….ane
Ethers
Are compounds with the general formula:
The center of the ether functional group is the oxygen.
Have two lone pairs of electrons on the oxygen. This forces the molecular geometry on the ether
oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.
Ethers: Examples
Ethers: Examples
Summary of Alcohols & Ethers
C - S Bonds Organic Compounds
1. Thiols
2. Thioethers
3. Disulfides
Thiols
IUPAC ending…thiols
Thiols
Are sometimes called sulfides. Are organic compounds containing a sulfhydryl
group, -SH, substituted for a hydrogen atom. Are the sulfur analogue of alcohols. Sulfur takes
the place of oxygen in the hydroxyl group of an alcohol.
Are stronger acids than alcohols. The –SH functional group itself is referred to as
either a thiol group or a sulfhydryl group.
Thiols
The center of the thiol functional group is the sulfur.
Have two lone pairs of electrons on the sulfur. This forces the molecular geometry on the thiol
sulfur to be BENT. The C–S–H angles approach 90°.
Thiols
Classified according to the number of carbon atoms bonded directly to the carbon containing the thiol group.
The names of thiols start with the name of the alkyl but end with the suffix –thiol.
Thiols
Can have more than one sulfhydryl group, and also variations where alkenes, alkynes or aromatics are involved.
Use a prefix for multiple thiol groups.
Thiols: Examples
Thioethers
IUPAC ending….sulfide
Thioethers
Are sometimes called sulfides. Are compounds with the general formula:
The center of the thioether functional group is the sulfur.
A thioether is similar to an ether except that it contains a sulfur atom in place of the oxygen.
Thioethers
Have two lone pairs of electrons on the sulfur. This forces the molecular geometry on the
thioether sulfur to be BENT. This portion of the molecule is flat, with bond
angles of 90 degrees.
90⁰
Thioethers: Examples
Thioethers: Examples
Disulfides
IUPAC ending…..disulfide
Disulfides
Another class of sulfur containing molecules that have important biological implications.
Have the generic formula:
Are products from the oxidation of two thiols.
Disulfides The center of a disulfide functional group has two
sulfur atoms single bonded to each other and to two different carbon atoms.
Have two lone pairs of electrons on each sulfur. This forces the molecular geometry on the
thioether sulfur to be BENT.
Disulfides
Are named by naming the R groups attached to the sulfur atoms followed by the suffix -disulfide.
Dimethyldisulfide
Disulfides: Examples
Disulfides: Examples
Disulfides: Examples
Carbon and Nitrogen Organic Compounds
1. Amines
2. Nitriles
Amines
1. IUPAC ending ….amine
2. Prefix is …amino
Amines
Are organic compounds that contain nitrogen and are basic.
The general form of an amine is:
R represents an alkyl group, but either or both of the hydrogens may be replaced by other groups and still retain its class as an amine.
Amines
The center of the amine functional group is the nitrogen.
Have one lone pair of electrons on the nitrogen in addition to the single bonds.
This forces the molecular geometry on the amine nitrogen to be trigonal pyramid.
This portion of the molecule is not flat, with bond angles of 109 degrees.
Amines
The common names for simple aliphatic amines consist of the alkyl group followed by the suffix -amine.
The amino group (-NH2) is named as a substituent in more complicated amines, such as those that incorporate other functional groups or in which the alkyl groups cannot be simply named.
Amines
Are classified according to the number of carbon atoms bonded directly to the nitrogen atom.
Amines: Examples
Amines: Examples
Nitriles
1. IUPAC ending is …..nitrile
2. Prefix is …..cyano
Nitriles
Are organic compounds that have a
functional group.
Have one lone pair of electrons on the nitrogen
in addition to one triple bond with a carbon atom.
This forces the molecular geometry on the cyano
nitrogen to be linear.
Nitriles
The common names for simple nitriles consist of the alkane/alkyl followed by the suffix -nitrile.
The cyano group (−C≡N) is also used interchangeably.
Nitriles: Examples
Carbonyl Organic Compounds
1. Aldehydes
2. Ketones
Aldehydes (CHO)
IUPAC ending is …al
Aldehydes
Are compounds containing a carbonyl group with a hydrogen attached at end and an organic group of carbons at the other side.
The center of the aldehyde functional group is the carbon double bond oxygen.
Aldehydes
Have two lone pairs of electrons on the oxygen. With three atoms attached to this carbon, the
molecular geometry is trigonal planar. This portion of the molecule is flat, with bond
angles of 120 degrees.
Aldehydes
IUPAC name includes the prefix from the alkyl groups and the suffix –al.
Aldehydes
IUPAC name for cyclic aldehydes includes the prefix cyclo and the suffix carbaldehyde.
Aldehydes: Examples
Ketones
IUPAC ending is …one
Ketones
Are compounds containing a carbonyl group with two hydrocarbon groups attached to it.
The center of the ketone functional group is the carbon double bond oxygen.
Ketones
Have two lone pairs of electrons on the oxygen. With three atoms attached to this carbon, the
molecular geometry is trigonal planar. This portion of the molecule is flat, with bond
angles of 120 degrees.
Ketones
IUPAC name includes the prefix from the alkyl group and the suffix -one.
For more than one ketone group, use a prefix.
Ketones: Examples
Summary of Aldehydes & Ketones
Carboxyl Derivatives
1. Carboxylic Acids
2. Esters
3. Amides
4. Thioesters
Carboxyl Derivatives
Are derivatives of carboxylic acids.
Can be distinguished from aldehydes and
ketones by the presence of a group
containing an electronegative heteroatom -
usually oxygen, nitrogen, or sulfur – bonded
directly to the carbonyl carbon.
Carboxyl Derivatives
Have two sides:
1. The carbonyl group attach to an alkyl group. This is called an acyl group.
2. The heteroatom-containing group, refer to as the ‘acyl X' group
Carboxylic Acids
IUPAC ending is …oic acid
Carboxylic Acids
Are important intermediate products for the production of esters and amides.
Are hydrocarbon derivatives for which the functional group is the carboxyl group.
The center of the acid functional group is the carbon double bonded to an oxygen and single bonded to a hydroxyl group.
Carboxylic Acids
Each oxygen atom has a pair of lone electrons. With three atoms attached to this carbon, the
molecular geometry is trigonal planar. This portion of the molecule is flat, with bond angles of 120 degrees.
An additional molecular geometry is centered on the oxygen of the - OH group. This is bent.
Carboxylic Acids
In the IUPAC system, the –e ending in alkane is removed from the name of the parent chain and is replaced -anoic acid for the COOH acidic bond system.
Carboxylic Acids
Cyclic carboxylic acids that are saturated are called cycloalkane carboxylic acids.
Dicarboxylic acids are known as alkanedioic acids.
Carboxylic Acids
Carboxylic Acids: Examples
Carboxylic Acids: Examples
Esters
IUPAC ending …oate
Esters
Are compounds with the general formula:
The center of the ester functional group is the carbon double bonded to an oxygen and single bonded to an oxygen attached to an alkyl group.
Esters
Each oxygen atom has a pair of lone electrons. With three atoms attached to this carbon, the
molecular geometry is trigonal planar. This portion of the molecule is flat, with bond angles of 120 degrees.
An additional molecular geometry is centered on the oxygen with all single bonds. This is bent.
Esters
Complex esters are more frequently named using the systematic IUPAC name, based on the name for the alkyl group followed by the suffix –oate.
Cyclic esters are called lactones.
Esters: Examples
Esters: Examples
Esters: Examples
Amides
IUPAC ending is …amide
Amides
Also known as an acid amide. Are formed when carboxylic acids react with
amines. Are nitrogen-containing organic compounds with
the general formula
Amides
The center of the amide functional group is the carbon double bonded to oxygen and single bonded to nitrogen.
Classified according to the number of carbons attached directly to the nitrogen atom:
Amides
The oxygen atom has two lone pair of electrons. The nitrogen atom has one pair of lone electrons.
With three atoms attached to this carbon, the molecular geometry is trigonal planar. This portion of the molecule is flat, with bond angles of 120 degrees.
Amides
The molecular geometry centered on the nitrogen is bent and also flat as an extension of the trigonal planar geometry.
Amides
In the IUPAC system: For primary amides, the –e is removed from the
alkane name and the suffix -amide is added.
Amides
For 2⁰ and 3⁰ amides, alkyl groups attached to the nitrogen are named as substituents.
The letter N is used to indicate they are attached to the nitrogen.
For more than one of the same substituent groups, use a prefix.
Amides
Amides
Amides: Example
Amides: Example
Amides: Example
Amides: Example
Thioesters
1. IUPAC ending….-thioate or -carbothioate
2. Prefix….thio & ending….-ate or -carboxylate
Thioesters
Are the product of esterification between a carboxylic acid and a thiol.
Are compounds with the functional group:
The center of the thioester functional group is the carbon double bonded to an oxygen and single bonded to sulfur attached to an alkyl group or hydrogen.
Thioesters
The oxygen and sulfur atoms, each, have two sets of lone pairs electrons.
With three atoms attached to this carbon, the molecular geometry is trigonal planar. This portion of the molecule is flat, with bond angles of 120 degrees.
Thioesters
The molecular geometry centered on the sulfur is bent and also flat as an extension of the trigonal planar geometry.
Thioesters
In the IUPAC system, the name consist of the alkyl group followed by the alkane with the suffix –thioate or –carbothioate
Alkyl groups attached to the sulfur are named as substituents. The letter S is used to indicate they are attached to the sulfur.
S-Methyl ethanethioate (IUPAC)
Thioesters
For common names, the name consist of the alkyl group followed by the prefix “thio” before the common name with the suffix –ate or -carboxylate.
Alkyl groups attached to the sulfur are named as substituents. The letter S is used to indicate they are attached to the sulfur.
S-PENTACHLOROPHENYL PENTACHLORO-1,3-BUTADIENE-1-THIOCARBOXYLATE
Thioesters: Examples
Thioesters: Examples
Summary of Carboxyl Derivatives
Summary of Functional Groups
Organic Reactions
1. Chemical Bonds2. Non-polar Reactions
3. Polar Reactions4. Classifications
Chemical Bonds in Reactions
1. Bond Breaking
2. Bond Forming
Chemical Bond Breaking
Polar reactions involve heterolytic bond cleavage
Radical reactions involve homolytic bond cleavage
Chemical Bond Making
Non-polar Reactions
Free Radicals Formation
Free Radicals
Are neutral and electron-deficient. They do not meet the octet rule. Examples:
Free Radicals
Stability of free radicals:
Free Radicals
React to complete its valence shell.
General Form:
Non-polar Reactions
Non-polar Reactions
Termination step:
Polar Reactions
1. Nucleophiles
2. Electrophiles
Lewis acid-base definition: transfer of electron pair from a base to an acid
Definitions
Nucleophiles
Are attracted to a positively charged cations or atoms with partially positive dipole.
Share or transfer its electrons with an electrophile during a reaction.
Nucleophiles
Can be negatively charged anions, neutral ions, molecules with a lone pair of electrons or at least one π bond.
Because nucleophiles donate electrons, they are by definition Lewis bases.
Nucleophiles: Examples
Nucleophiles: Examples
Electrophiles
Atoms that are positively charged, carry a partially positive dipole, or does not have an octet of electrons.
Attracted to electrons of nucleophiles in a chemical reaction.
Because electrophiles accept electrons, they are Lewis acids.
Electrophiles
H+ NO+
HCl Alkyl halides Acyl halides Cl2
Br2
Organic peracids Carbenes Radicals BH3
Carbonyl compounds Diisobutylaluminium
hydride (DIBAL)
The most common in organic syntheses are:
Polar Reactions
Nucleophiles – transfers electrons to an electrophilic atom
Electrophiles - accept electrons from a nucleophilic atom
Polar Reactions
General Form:
Products never exceed the octet rule.
Polar Reactions
The nucleophilic site can be neutral or negatively charged.
Polar Reactions
The electrophilic site can be neutral or positively charged.
Organic Reactions
1. Addition2. Elimination 3. Substitution
4. Rearrangement5. Condensation
6. Esterification7. Hydrolysis
8. Oxidation & Reductions
9. Combustion
Addition Reactions
The components of an organic molecule A–B are added to the carbon atoms in a C=C bonds.
Involve the conversion of a π bond into 2 σ bonds.
General form: A + B → C
Addition Reactions
Symmetrical alkenes produce one product.
Unsymmetrical alkenes produce racemic mixtures.
Addition Reactions
Alcohols are often produced by addition reactions.
Initial attack by the π bond of an alkene on a Hδ+ of H3O+ produces a carbocation.
The carbocation then undergoes nucleophilic attack by a lone pair of electrons from H2O.
This is followed by elimination of H+ to form the alcohol.
Addition Reactions
Addition Reactions
With symmetrical alkenes, addition of hydroxyl group produces one type of alcohol.
Addition Reactions
With unsymmetrical alkenes, addition of
hydroxyl group produces different types of
alcohols depending on the location of the
double bond
+
Addition Reactions
Formation of hemiketals & hemiacetals: Reactions between an acohol and either a
ketone or aldehyde.
Elimination Reactions
The removal or “elimination” of adjacent atoms from a molecule.
Two σ bonds are lost, replaced by a new π bond.
The dehydration reaction of alcohols to generate alkene proceeds by heating the alcohols in the presence of a strong acid, such as sulfuric or phosphoric acid, at high temperatures.
Elimination Reactions
The required range of reaction temperature
decreases with increasing substitution of the
hydroxyl carbon:
1° alcohols: 170° - 180°C
2° alcohols: 100°– 140 °C
3° alcohols: 25°– 80°C
Elimination Reactions
If the reaction is not sufficiently heated, the alcohols do not produce alkenes, but they react with one another to form ethers (Williamson Ether Synthesis).
Elimination Reactions
General form: A → B + C
Elimination Reactions
1⁰ Alcohols
Elimination Reactions
2⁰ Alcohols
Elimination Reactions
In dehydration reactions of alcohols, hydride
or alkyl shifts relocate the carbocation to a
more stable position.
The dehydrated products are a mixture of
alkenes, with and without carbocation
rearrangement.
Elimination Reactions
Hydride or alkyl shifts are the result of
hyperconjugation. The interaction between the
filled orbitals of neighboring carbons and the singly
occupied p orbital in the carbocation stabilizes the
positive charge in carbocation.
The tertiary cation is more stable than a secondary
cation, which is more stable than a primary cation.
Elimination Reactions
Hydride shift:
Elimination Reactions
Alkyl shift:
Substitution Reactions
Nucleophilic substitution reactions. An electronegative atom is replaced by
another more electronegative atom, called a stronger nucleophile.
The stronger nucleophile must possess a pair of electrons and have a greater affinity for the electropositive carbon atom than the original electronegative atom.
A σ bond is replaced by another σ bond .
Substitution Reactions
General form: A + B → C + D
Non-polar reactions:
Substitution Reactions
Polar reactions:
Rearrangement Reactions
Are isomerisation reactions. An organic molecule changes structure. Constitutional change in carbon skeleton. Reaction may involve changes in bond type.
General form: A → B
Rearrangement Reactions
Condensation Reactions
Two molecules combine to form one single
molecule with the loss of a small molecule.
When this small molecule is water, it is known
as a dehydration reaction.
Other possible small molecules lost include
hydrogen chloride, methanol, or acetic acid.
Condensation Reactions
When two separate molecules react, their condensation is termed intermolecular.
The condensation of two amino acids to form a peptide bond (red) with expulsion of water (blue).
Condensation Reactions
When a condensation is performed between
different parts of the same molecule, the
reaction is termed intramolecular
condensation.
In some cases this leads to ring formation.
Condensation Reactions
Esterification Reactions
Esters are obtained by refluxing a carboxylic acid with an alcohol in the presence of an acid catalyst.
The reaction is driven to completion by using an excess of either the alcohol or the carboxylic acid, or by removing the water as it forms.
Alcohol reactivity order : CH3OH > 1o > 2o > 3o (steric effects).
Esterification Reactions
A carboxylic acid and an alcohol react together under acidic conditions to form an ester and lose water.
Esterification Reactions
Esters can also be made from other carboxylic acid derivatives, especially acyl halides and anhydrides, by reacting them with the appropriate alcohol in the presence of a weak base.
If a compound contains both hydroxy- and carboxylic acid groups, then cyclic esters or lactones can form via an intramolecular reaction. Reactions that form 5- or 6-membered rings are particularly favorable.
Esterification Reactions
Pericyclic esters
Hydrolysis
A reaction in which water is a reactant, and
becomes part of the reaction product.
A number of organic compounds undergo
hydrolysis with water, such as amides, esters,
halogenoalkanes and acyl halides.
Hydrolysis
Reactions require a catalyst.
The catalyst is either an acid (H+ ions) or alkali
(OH- ions).
Hydrolysis might involve refluxing in the
presence of dilute hydrochloric acid or sodium
hydroxide solution.
Hydrolysis
In the overall reaction, a bond in an organic molecule is broken.
A water molecule also breaks into ions. The -OH group from water is added to one
end of the organic molecule and the remaining H atom is added to the other.
Hydrolysis of an Ester:
The addition of a strong acid, such as dilute hydrochloric acid, is required to free the carboxylic acid molecule.
In the base-catalyzed, the carboxylic acid molecule loses a proton to a hydroxide ion.
Hydrolysis of Amides & Nitriles:
Amide acid catalyzed - HCl
Nitrile acid catalyzed – HCl or H2SO4
Hydrolysis of Halogenalkanes:
Hydrolysis of Aromatics
Summary of Hydrolysis Reactions
1. The hydrolysis of a primary amide:
RCONH2 + H2O → RCOOH + NH3
2. The hydrolysis of a secondary amide:
RCONHR' + H2O → RCOOH + R'NH2
Summary of Hydrolysis Reactions
3. The hydrolysis of an ester:
RCOOR' + H2O → RCOOH + R'OH
4. The hydrolysis of a halogenoalkane:
RBr + H2O → ROH + H+ + Br-
Reduction & Oxidation (REDOX) Reactions
1. Oxidation States
2. Oxidations
3. Reductions
Definitions
Oxidation-Reduction reactions: Involve changes in oxidation state at one or more
atoms. Can often be identified by changes in the number
of oxygen atoms at a particular position in the hydrocarbon skeleton or in the number of bonds between carbon and oxygen at that position.
It is not consider an oxidation or reduction reaction: Addition or loss of H+, H2O, HX.
Definitions
Oxidation: The oxidation state increases Loss of H2 Loss of a C-H bond Addition of O or O2
Formation of a C-O bond or equivalent (C-Cl, CΞN, C-S)
Addition of X2 (halogens)
Definitions
Reduction: The oxidation state decreases Addition of H2 or H-
Formation of a C-H bond Loss of O or O2
Loss of a C-O bond or equivalent Loss of X2.
An increase in the number of hydrogen atoms in a hydrocarbon is often an indication of a reduction.
Oxidation States
Carbon oxidation states are assigned on the basis of the electronegativity of attached atoms. For each bond to a more electronegative atom
give +1. For each bond to a less electronegative atom
(even H) give –1. For each bond to carbon give 0.
Oxidation States
Oxidation States
In nitrogen-containing compounds, the number of carbon–nitrogen bonds changes with the oxidation state of carbon.
Oxidation States
Assign oxidation states to all atoms in the following structure:
C HO
C
H
CC
O
H
H
H
H
HH
Assign oxidation states to all atoms in the following structure:
-2
C+1 HO +3
C
H+1
C-2
-3
C
-2
O
+1H
+1
H
HH+1
H+1H+1+1
-2
1) Identify if the following reactions are oxidation-reduction reactions.
2) For any that are, identify the atoms that are oxidized and reduced.
Br I+ NaI +NaBr
+ H2
OH
+K-O
O+ KMnO4 + MnO2 + H2O
Problem
Problem
No, both Br and I are more electronegative than C
-2
+ H2
Yes, the carbon atoms are reduced, the H2 molecule is oxidized
Problem
Summary of Oxidation States
REDOX Reactions of Alcohols
Alcohols can undergo either oxidation or
reduction type reactions.
Oxidation is a loss of electrons.
Reduction is a gain of electrons.
Oxidation of Alcohols
1⁰ and 2⁰ alcohols are easily oxidized by a variety
of reagents.
The most common reagents used:
Pyridinium chlorochromate (PCC)
Potassium permanganate
Thermal dehydrogenation
Oxidation of Alcohols
The most common reagent used for oxidation of 2⁰
alcohols to ketones is chromic acid, H2CrO4.
3⁰ alcohols are resistant to oxidation because they
have no hydrogen atoms attached to the oxygen
bearing carbon (carbinol carbon).
Oxidation of 1 ⁰ Alcohols
1⁰ alcohols are easily oxidized just like 2⁰ alcohols. The product of oxidation is an aldehyde. The aldehyde is easily oxidized to an acid as a result
of “over-oxidation”.
A reagent that selectively oxidizes a 1⁰ alcohol to an aldehyde is pyridinium chlorochromate, PCC.
Oxidation of 2 ⁰ Alcohols
The alcohol and chromic acid produce a chromate ester, which then reductively eliminates the Cr species.
The Cr is reduced (VI IV), the alcohol is oxidized to a ketone.
Summary of Oxidation of Alcohols
Reduction of Alcohols
Normally an alcohol cannot be directly reduced to
an alkane in one step.
The –OH group is a poor leaving group and
hydride displacement cannot happen.
Instead, the hydroxyl group is easily converted into
other groups that are better leaving groups, and
allow reaction to move forward.
Reduction of Alcohols
Commons reagents are tosyl chloride and lithium aluminum hydride (LiAlH4).
The reaction involves the formation of a tosylate. The tosylates can undergo either substitution or
elimination reactions.
Reduction of Alcohols
The tosylate reduces to cyclohexane very easily with lithium aluminum hydride.
Reduction of Carboxylic Acids
Carboxylic acids are reduced to 1⁰ alcohols.
Reduction of Esters
Esters are reduced to 1⁰ alcohols.
Reduction of Amides
Amides are reduced to 1⁰, 2⁰, or 3⁰ amines.
Reduction of Aldehydes
Aldehydes and ketones are reduced to 1⁰ and 2⁰ alcohols respectively.
Summary REDOX Reactions
Combustion Reactions
The reaction of an organic molecule with
oxygen to form carbon dioxide, heat/energy
and water.
Combustion Reactions
Alkanes:
Alkenes:
Alcohols
Introduction to Biochemistry
Part III – Foundations of Organic Chemistry in Biochemistry
Biochemistry
1. Macromolecules
2. Functional Groups
3. Organic Reactions
4. Carbohydrates
Definitions
Biochemistry is the study of chemical compounds and reactions which occur in living organisms.
It overlaps extensively with organic chemistry since most compounds in living cells contain carbon.
Biochemistry involves the study of carbohydrates, lipids, proteins and nucleic acids, which are the types of molecules involved in the chemistry of living organisms.
Definitions
Hydrogen bonds – ionic and hydrophilic interactions between a polar or ionic molecules and water.
Definitions
Hydrophobic interactions - tendency of nonpolar substances to aggregate in aqueous solution and exclude water molecules.
Macromolecules
All living things contain these organic molecules: carbohydrates, lipids, proteins, and nucleic acids.
These organic molecules are often called macromolecules.
They may be very large, containing thousands of carbon and hydrogen atoms and bonded to other smaller molecules.
They are classified as polar, ionic or non-polar molecules.
Macromolecules
Polar and ionic molecules have either full or
partially (dipole) positive or negative charges.
They are attracted to water molecules.
They are said to be hydrophilic because
they interact with (dissolve in) water by
forming hydrogen bonds.
Macromolecules
Nonpolar molecules are neutral (NO dipole).
They are NOT attracted to water or polar
molecules.
They are hydrophobic because they DO
NOT dissolve in water or form hydrogen
bonds.
Macromolecules
Nonpolar molecules are hydrophobic.
Polar and ionic molecules are hydrophilic.
Macromolecules
Portions of macromolecules may be hydrophobic and other portions of the same molecule may be hydrophilic.
The chains may be branched or form rings.
Functional Groups in Biochemistry
1. Hydrocarbons
2. Aromatics
3. Common Functional Groups
Functional Groups
Some functional groups are polar and others can ionize.
For example, if the hydrogen ion is removed from the COOH group, the oxygen will retain both of the electrons and will have a negative charge.
The hydrogen that is removed leaves behind its electron and is now a hydrogen ion (proton, cation, H+).
Functional Groups
If polar or ionizing functional groups are attached
to hydrophobic molecules, the molecule may
become hydrophilic due to the functional group.
Some ionizing functional groups are: -CO2H, -OH,
R2-C=O, and -NH2.
Hydrocarbons
Cycloalkanes
Cycloalkanes
Cycloalkanes
Aromatic Compounds
Aromatic Compounds
Aromatic Compounds
Aromatic Compounds
Common Functional Groups
Common Functional Groups
Summary of Functional Groups
Summary of Functional Groups
Important bond linkages in Biochemistry:
Organic Reactions Classes:
1. Group Transfer
2. REDOX
3. Eliminations, Isomerizations,
Rearrangements
4. C-C Bond Making & Breaking
5. Hydrolysis
Group Transfer Reactions
Nucleophilic Substitution Transfer an electrophile from one nucleophile
to another. Commonly transferred groups:
1. Acyl
2. Phosphoryl
3. Glycosyl
4. Amino
Group Transfer Reactions: Acyl GroupAcylation Reactions
Group Transfer Reactions: Phosphoryl GroupPhsophorylation Reaction
Group Transfer Reactions: Glycosyl Group
Glycosylation Reactions
Group Transfer Reactions: Amino Group
Transamination Reactions
REDOX Reactions
Involve the loss or gain of electrons. C-H bond cleavage with the loss of electrons. Use of electron acceptors:
NAD+
FAD+
NADP+
Coenzyme Q Fe centers in Cytochrome C
REDOX Reactions
Electrons are highly reactive and do not exist
on their own in cells.
If oxidation occurs to one molecule in the cell,
reduction must immediately to another
molecule.
REDOX Reactions
REDOX Reactions
REDOX Reactions
REDOX Reactions
Elimination Reactions
Formation of alkenes Products are:
Trans (anti) – Major Cis (syn)
Elimination of: Water Ammonia 1⁰ Amines Alcohols
Elimination Reactions
Types of Mechanisms:1. Concerted
2. Carbocation Formation: C-O bond breakage
3. Carbanion Formation: C-H bond breakage
Two Types of Reactions:1. Dehydrations
2. Deaminations
Elimination Reactions: Concerted & Carbocation
Elimination Reactions: Carbanion
Elimination Reactions: Dehydration
Enzyme catalyzed reactions.
Two Types of Enzyme-Catalysis:
1. Acid: Protonation of OH group
2. Base: Abstraction of a proton
Elimination Reactions: Dehydradation
Other Dehydration Reactions
Condensation reactions. Involved in the assembly of all four types of
macromolecules. An H atom is removed from a functional
group on one molecule, and an OH group is removed from another molecule.
Products: a larger molecule + water
Condensation of Amino Acids
Condensation of Saccharides
Condensation of Fatty Acids
Elimination Reactions: Deaminations
Elimination Reactions: Deaminations
Isomerization Reactions
Relocation of a = bond.
Intramolecular shift of a proton.
Most common are base catalyzed reactions.
Isomerization Reactions
Rearrangement Reactions
Breaking and reforming C-C bonds to
rearrange carbon atoms in the backbone of a
molecule.
Useful in oxidation of odd number of carbon
atoms fatty acids and several amino acids.
Rearrangement Reactions
C-C bond Breaking & Making Reactions Addition of a nucleophilic carbanion to an
electrophilic carbon atom. Most common electrophilic carbon atoms are
sp2 hybridized carbonyl carbon atoms:
1. Aldehydes
2. Ketones
3. Esters
4. Carbon Dioxide
C-C bond Breaking & Making Reactions1. Condensation
Aldol Claisen Ester Other Condensations Reactions:
o Amino Acids o Saccharides o Fatty Acids
2. Decarboxylations
Condensation Reactions: Aldol
Condensation Reactions: Claisen Esters
Decarboxylation Reactions
Removes a carboxyl group Releases carbon dioxide.
Decarboxylation Reactions
Decarboxylation Reactions: Citric Cycle
Decarboxylation Reactions: Precursors of the Citric Cycle
Hydrolysis
Involved in the breakdown of macromolecules into their monomers.
Water is added to break the bonds between monomers.
H from the water is added to one molecule, and the OH group is added to the adjacent monomer.
Covalent bond between monomers breaks to form two smaller molecules.
Hydrolysis of Proteins
Hydrolysis of Polysaccharides
Hydrolysis of Fats
Synthesis of Common Functional Groups
Synthesis of Common Functional Groups
Biochemistry: The Chemistry of the Human Body
Part IV - Macromolecules
Macromolecules
Many of the common macromolecules are synthesized from monomers.
Carbohydrates
1. Monosaccharides
2. Disaccharides
3. Polysaccharides
Carbohydrates
Compounds which provide energy to living cells.
Made up of carbon, hydrogen and oxygen with a ratio of two hydrogens for every oxygen atom.
The name carbohydrate means "watered carbon" or carbon with attached water molecules.
Are used directly to supply energy to living organisms.
Carbohydrates
Many carbohydrates have empirical formuli which would imply about equal numbers of carbon and water molecules.
The general formula for carbohydrates is (CH2O)n.
The names of most sugars end with the letters -ose.
The pentose sugars ribose and deoxyribose are important in the structure of nucleic acids like DNA and RNA.
Carbohydrates
Three key classification schemes for sugars are:
1. Monosaccharides
2. Disaccharides
3. Polysaccharides
Monosaccharides
Simple sugars, having 3 to 7 carbon atoms. Are linear molecules but in aqueous solution they
form a ring form structure. In aqueous solution, monosaccharides with
five or more C atoms form cyclic ring structures.
These 6-membered ring compounds are called pyranoses.
These rings form due to a general reaction that occurs between alcohols and aldehydes or ketones to form derivatives called hemiacetals or hemiketals.
Monosaccharides
Monosaccharides
May form several types of stereoisomers since
they share the same molecular formula.
Four Classes of Stereoisomers:
1. Diastereomers
2. Enantiomers
3. Epimers
4. Anomers
Monosaccharides: Isomers
Monosaccharides: Diastereomers
Stereoisomers that are not mirror images of each other.
Diastereomers for the molecular formula C5H10O5:
Monosaccharides: Diastereomers
Diastereomers for the molecular formula C6H12O6:
Monosaccharides: Enantiomers
Stereoisomers that are mirror images of each other. Two types: D or L
Monosaccharides: Epimers
Two diastereomers that differ around one chiral center.
Monosaccharides: Anomers
Stereoisomers that differ in the configuration around the anomeric carbon.
Two types of anomers are: α or β. In hemiacetals, the anomeric carbon is at position 1.
Monosaccharides: Anomers
Monosaccharides: Anomers
In hemiketals, the anomeric carbon is at position 2.
Disaccharides
Glycosides
Formed from two monosaccharides.
The -OH of one monosaccharide condenses with
the intramolecular hemiacetal of another
monosaccharide, forming a glycosidic bond.
Glycosidic bonds can be: α or β.
Disaccharides
Disaccharides
Common disaccharides are:
1. Sucrose
2. Lactose
3. Maltose
4. Trehalose
Disaccharides
Sucrose
Prevalent in sugar cane and sugar beets
Sucrose
Lactose
Found exclusively in milk.
Lactose
Maltose
Major degradation product of starch.
Maltose
Trehalose
Found in bacteria, yeast, invertebrates, mushrooms and seaweed.
Glycosidic Linkages:
Protects organisms from extreme temperatures and drying out.
Trehalose
Is used: As a preservative for foods and to minimize
harsh flavors and odors. As a moisturizer in cosmetics. As an natural sweetener for diabetics. Antioxidant to stabilize proteins and lipids in
neurodegenerative diseases like Alzheimer's and Huntington's Disease.
To protect organs for transplants.
Trehalose
Is: Involved in the regulation of developmental
and metabolic processes in plants. The major transport sugar in shrimp, insects
and plants. The major carbohydrate energy storage
molecule used by insects for flight.
Trehalose
In plants, synthesis is carried out by trehalose phosphate synthase and trehalose phosphatase:
Trehalose
Trehalose
Degradation:
Trehalase
Polyssacharides
Ten or more monosaccharides bonded together to form long chains.
The chains are typically contain hundreds of monosaccharaides.
Can have one, two or many different types of monosaccharides.
1. Homopolysaccharides
2. Heteropolysaccharides
Polyssacharides
Polyssacharides
Are classified as:
1. Cellulose
2. Chitin
3. Glycogen
4. Starches
Cellulose & Chitin
Are polysaccharides with 1500 glucose rings chain together.
Function is support and protection. The monomers of cellulose and chitin are
bonded together in such a way that the molecule is straight and unbranched.
The molecule remains straight because every other glucose is twisted to an upside-down position compared to the two monomers on each side.
Cellulose & Chitin
Humans and most animals do not have the necessary enzymes needed to break the linkages of cellulose or chitin.
Some bacteria and some fungi produce enzymes that digest cellulose.
Some animals have microorganisms in their gut that digest cellulose for them.
Fiber is cellulose, an important component of the human diet.
Cellulose
Is composed of beta-glucose monomers. Cellulose fibers are composed of long parallel
chains of these molecules. The chains are attached to each other by
hydrogen bonds between the hydroxyl groups of adjacent molecules.
The cell walls of plants are composed of cellulose.
Cellulose
Chitin
The cell walls of fungi and the exoskeleton of arthropods are composed of chitin.
The glucose monomers of chitin have a side chain containing nitrogen.
Chitin
Glycogen
Animals and some bacteria store extra carbohydrates as glycogen.
In animals, glycogen is stored in the liver and muscle cells.
Between meals, the liver breaks down glycogen to glucose in order to keep the concentration of glucoses in the blood stable.
After meals, as glucose levels in the blood rise, glucose is removed from the blood and stored as glycogen.
Glycogen
Glycogen
Homopolymer of glucose. Two types of glycosidic linkage: α–(1, 4) for straight chains α–(1, 6) for branched chains, occurring every
8-10 residues.
Glycogen
Glycogen is a very compact structure that
results from the coiling of the polymer chains.
This compactness allows large amounts of
carbon energy to be stored in a small volume,
with little effect on cellular osmolarity.
Starches
Starch and glycogen are composed of 300 –
1000 alpha-glucose units join together.
It is a polysaccharide which plants use to
store energy for later use.
Starches are smaller than cellulose units, and
can be more readily used for energy.
Starches
Foods such as potatoes, rice, corn and wheat
contain starch granules which are important energy
sources for humans.
The human digestive process breaks down the
starches into glucose units with the aid of enzymes,
and those glucose molecules can circulate in the
blood stream as an energy source.
Starches
Amylopectin is:
1. A form of starch that is very similar to
glycogen.
2. Branched but have less branches than
glycogen.
Amylose is:
A form of starch that is unbranched.
Starches
Starches & Glycogen
The bond orientation between the glucose subunits of starch and glycogen allows the polymers to form compact spirals.
Summary of Carbohydrates CHO Monosaccharides:
simple sugars Functional group(s):
Carboxyl Hydroxyl
Disaccharides Polysaccharides
Summary of Carbohydrates
Summary of Carbohydrates
Summary of Carbohydrates
Proteins
Definitions
Peptide - a short chain of amino acids bonded together.
Oligopeptide- a short chain of at least 2 amino acids and up to 20 amino acids long.
Polypeptide - a longer chain of many amino acids, typically 50 or more.
Proteins - consist of one or more polypeptides, subunits, chains or domains.
Proteins
Are the building materials for living cells, appearing in
the structures inside the cell and within the cell
membrane. About 75% of the dry weight of our bodies.
They contain carbon, hydrogen, oxygen, nitrogen,
sulfur and phosphorus.
Protein molecules are often very large and are made
up of hundreds to thousands of amino acid units.
Proteins
Functions:
Transport oxygen (Hb)
Build tissue (Muscle)
Copy DNA for cell replication
Support the body as structural proteins
Components of cell membranes (receptors, membrane
transport, antigens)
Control metabolic reactions as regulatory proteins called
enzymes
Proteins
Functions:
Hormones
Storage (egg whites of birds, reptiles; seeds)
Protection (antibodies)
Toxins (botulism, diphtheria) Some proteins are in solution in the blood and other body
fluids. Others are solids that make up the framework of tissue,
bone and hair.
Proteins
Proteins can be characterized as extremely long-
chain polyamides. The amides contain nitrogen,
and nitrogen composes about 16% of the protein
atomic content.
In the cell, the DNA directs or provides the
master blueprint for creating proteins, using
transcription of information to mRNA and then
translation to actually create proteins.
Proteins
Proteins are synthesized via condensation of amino
acids under the influence of enzyme catalysts.
The 20 amino acids are combined in different ways to
make up the 100,000 or so different proteins in the
human body.
The amino acid units in a protein molecule are held
together by peptide bonds, and form chains called
polypeptide chains.
Proteins
Proteins
During translation, the protein goes through several different structural stages:1. Primary
2. Secondary
3. Tertiary
4. Quaternary Final structures may undergo post-
translational modifications based on their determined function.
Proteins
Subunit or domain
Proteins: Primary Structure
The sequence of amino acids in the polypeptide chain.
The sequence of the R groups determines the folding of the protein.
A change of a single amino acid can alter the function of the protein.
Sickle cell anemia - caused by a change of one amino acid from glutamine to valine.
Proteins: Primary Structure
Proteins: Secondary Structure
Folding and coiling due to H bond formation between carboxyl and amino groups of non-adjacent amino acid.
R groups are NOT involved. This bonding produces two common kinds of shapes
seen in protein molecules- coils, called alpha helices, and beta sheets.
A single polypeptide may contain many of these helices and sheets.
Proteins: Secondary Structures
AlphaBeta
Proteins: Tertiary Structure
The overall 3-dimensional shape of the polypeptide chain.
Hydrophobic interactions with water molecules are important in creating and stabilizing the structure of proteins.
Hydrophobic (nonpolar) amino acids aggregate to produce areas of the protein that are out of contact with water molecules.
Proteins: Tertiary Structure
Hydrophilic (polar and ionized) amino acids form hydrogen bonds with water molecules.
Hydrogen bonds and ionic bonds form between R groups to help shape the polypeptide chain.
Disulfide bonds are covalent bonds between sulfur atoms in the R groups of two different amino acids. These bonds are very important in maintaining the tertiary structure of some proteins.
Proteins: Tertiary Structure
Proteins: Tertiary Structure
The shape of a protein is typically described as
being globular or fibrous.
Globular proteins contain both coils and sheets.
Fibrous proteins are elongated molecules in
which either α-helices or β-pleated sheets are
the dominant structures.
Proteins: Tertiary Structure
Proteins: Quaternary Structure
Relationship among multiple polypeptide chains forming one protein structure.
Contain two or more tertiary structures that associate to form a single protein.
The overall 3-D structure is due to interactions between polypeptide chains after synthesis:
1. Hydrophobic & hydrophilic interactions
2. H- bonds
3. Ionic interactions
4. Disulfide bonds
Proteins: Quaternary Structure
Proteins: Enzymes
Some proteins are structural, but some are control proteins called enzymes.
These enzymes can be used in the synthesis of proteins, including their own synthesis.
Each protein, including enzymes, is made according to a pattern of nucleotides along a segment of the DNA called a "gene".
A single living cell contains thousands of enzymes.
Proteins: Enzymes
Proteins: Enzymes
Speed up the rate of chemical reactions.
Proteins are able to function as enzymes due
to their shape.
Enzyme molecules are shaped like the
reactants, allowing the reactants to bind closely
with the enzyme.
Proteins: Enzymes
Have a small a pocket located on the 3-D surface of the folded protein.
This is the binding site, where the substrate binds and chemical reactions take place .
The binding site matches the shape of the
substrate molecules.
The enzyme is then able to hold the substrate
molecules in the correct orientation for the
chemical reaction to proceed.
The enzyme itself does not participate in the
reaction and is not changed by the reaction.
Proteins: Enzymes
Other Kinds of Proteins
Simple proteins contain only amino acids.
Conjugated proteins contain other kinds of
molecules.
Three key classes of conjugated proteins:
1. Glycoproteins (carbohydrates)
2. Nucleoproteins (nucleic acids)
3. Lipoproteins (lipids)
Conjugated Proteins
Conjugated Proteins
Amino Acids
Are organic compounds. Each has a carboxyl group and an amino group
attached to the same carbon atom, called the alpha carbon.
Amino acids have the general form:
Amino Acids
There are 20 amino acids which make up the proteins, distinguished by the R-group.
The structure of the R-group determines the chemical properties of the amino acid.
Types of chemical properties:
1. Polar Charged
2. Nonpolar
3. Electrically Charged
Amino Acids: Polar Uncharged
Are hydrophilic and can form hydrogen bonds.
1. Serine
2. Threonine
3. Glutamine
4. Asparagine
5. Tyrosine
6. Cysteine
Amino Acids: Nonpolar
Are hydrophobic and are usually found in the center of the protein.
Also found in proteins which are associated with cell membranes.
1. Glycine2. Alanine3. Valine4. Leucine
5. Isoleucine6. Methionine7. Phenylalanine8. Tryptophan9. Proline
Amino Acids: Electrically Charged
Have electrical charges that can change depending on the pH.
1. Aspartic Acid
2. Glutamic Acid
3. Lysine
4. Arginine
5. Histidine
Amino Acids: Chemical Properties
The simplest amino acid is glycine. It fits in
tight spaces in the 3-D structure of proteins. It
contain hydrogen as an R group.
Cysteine can form covalent disulfide bonds in
3 and 4 structures.⁰ ⁰
Proline has a unique structure and causes
kinks in the protein chains.
Amino Acids
Amino acids are the structural elements from which proteins are built.
When amino acids bond to each other, it makes an amide bond.
This bond is formed as a result of a condensation reaction between the amino group of one amino acid and the carboxyl group of another.
Amino Acids
Amino acids can have either left-handed or right-handed molecular symmetry.
The most common are left-handed amino acids. These are the building blocks of proteins.
Amino Acids
The human body can synthesize all of the amino acids necessary to build proteins, except for the ten called the “essential amino acids”.
An adequate diet must contain these essential amino acids.
Typically, they are supplied by meat and dairy products, but if those are not consumed, some care must be applied to ensuring an adequate supply.
Amino Acids: Non-essential
The 10 amino acids that we can produce are:
alanine, asparagine, aspartic acid, cysteine,
glutamic acid, glutamine, glycine, proline,
serine and tyrosine.
Tyrosine is produced from phenylalanine, so
if the diet is deficient in phenylalanine,
tyrosine will be required as well.
Amino Acids: Essential
The essential amino acids are: arginine (required
for growing children), histidine, isoleucine, leucine,
lysine, methionine, phenylalanine, threonine,
tryptophan, and valine.
Humans do not have all the enzymes required for
the biosynthesis of essential amino acids.
Amino Acids
The failure to obtain enough of any of the 10 essential amino acids has serious health implications and can result in degradation of the body's proteins.
Muscle and other protein structures may be degraded to obtain the one amino acid that is needed.
The human body does not store excess amino acids for later use. The amino acids must be obtained from food daily.
Amino Acids
Summary of Proteins & Amino Acids
Monomer: amino acids 20 total, 9 or 10 essential
Functional group(s): Carboxyl Amino
Polymer Polypeptide Protein
Summary of Amino Acids
Nucleic Acids
Control the processes of heredity:
Transcription
Translation
Cell Replication
The key nucleic acids are:
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
Nucleic Acids
Nuclei acid consist of a long chain of units
called nucleotides.
Nucleotides are the basic structural units of
nucleic acids
The nucleotides are made up of a phosphate
group, a pentose sugar, and a nitrogen base.
Nucleic Acids
Nucleic Acids
The sugar ribose is characteristic of RNA.
The sugar deoxyribose is characteristic of
DNA.
Nucleic Acids
For RNA, the bases are adenine, guanine,
cytosine and uracil.
For DNA, the bases may be adenine, guanine,
cytosine or thymine.
Nucleic Acids
Nucleic Acids
The larger bases adenine and guanine are purines which differ in the kinds of atoms that are attached to their double ring.
The other bases (cytosine, uracil, and thymine) are pyrimidines, which differ in the atoms attached to their single ring.
The resulting DNA (deoxyribonucleic acid) contains no uracil, and RNA(ribonucleic acid) does not contain any thymine.
DNA
Stores information regarding the sequence of amino acids in each of the body’s proteins.
Is the master blueprint for the production of proteins and cell replication.
In protein synthesis, serves as a pattern for mRNA synthesis, in a process called transcription.
mRNA contains all the DNA information to manufacture a protein, in a process called translation.
DNA Structure
Is a double helix. The bases may be attached in any order. This
gives the vast number of possibilities of arrangements, making the genetic code diverse.
The bases are only attached by hydrogen bonds to their complementary base. This arrangement makes possible the separation of the strands and the replication of the DNA double helix.
DNA Structure
DNA Structure
Antiparallel
1. The end of a single strand that has the
phosphate group is called the 5’ end. The
other end is the 3’ end.
2. The two strands of a DNA molecule run in
opposite directions.
DNA Structure
DNA Structure
Complimentary base pairing
A-T
G-C
Two hydrogen bonds hold adenine to thymine.
Three hydrogen bonds hold cytosine to
guanine.
DNA Base Pairing
RNA
Is directly involved in the synthesis of proteins in a process called "translation".
mRNA itself is directed synthesized from DNA in a process called transcription.
mRNA is the template for the synthesis of all proteins.
RNA has many forms, but the three most important are messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).
RNA Structure
RNA Base Pairing
mRNA
The anti-sense strand is used as a template to
produce a single strand of mRNA.
The sequence of bases on a segment of DNA called
a gene is copied to a strand of mRNA with the
assistance of RNA polymerase.
The bases in the mRNA strand are complimentary to
the bases in DNA.
mRNA
The mRNA contains three-letter codes, called a codon. It is the code for one amino acid.
The sequence of codes in DNA therefore determines the sequence of amino acids in the protein.
mRNA
The mRNA has regions called introns and exons. Introns are not a part of the pattern for the protein
to be synthesized, so those segments are excised from the mRNA.
Exons are the only segments present before the mRNA's are released from the nucleus.
These pattern for protein synthesis is then read and translated into the language of amino acids for protein synthesis with the help of tRNA.
mRNA
tRNA
Is directly involved in the translation of the sequence of nucleotides in mRNA with rRNA.
The synthesis of tRNA itself is directed by the DNA in the cell that provides a pattern for the production of mRNA by "transcription".
When mRNA reaches rRNA to be translated, tRNA molecules with all the required amino acids must be present for the process to proceed.
Since most proteins use all twenty amino acids, all must be available, attached to appropriate tRNA molecules.
tRNA
Is commonly called a cloverleaf form.
Binds an amino acid at one end opposite to
the anticodon on the other end.
This anticodon will bind to a codon consisting
of three nitrogenous bases which specify an
amino acid according to the genetic code.
tRNA
The many types of tRNA have roughly the
same size and shape, varying from about 73
to 93 nucleotides.
Besides the usual bases A, U, G, and C, all
have a significant number of modified bases,
which are formed by modification after the
transcription.
tRNA
Letter Code Modified Bases
I Inocine
mI methylinosine
mG methylguanosine
m2G dimethylguanosine
Psi Pseudouridine
D Dihydrouridine
tRNA
All tRNAs have sequences of nucleotides that
are complementary to other parts of the
molecule and base-pair to form the five arms
of the tRNA.
Four of the arms are fairly consistent, but the
variable arm can range from 4 to 21
nucleotides.
tRNA
rRNA
Associates with a set of proteins to form ribosomes.
Physically moves an mRNA molecule and catalyze the assembly of amino acids into protein chains.
Binds tRNAs and various accessory molecules necessary for protein synthesis.
Ribosomes are composed of a large and small subunit, each of which contains its own rRNA molecule or molecules.
rRNA
Translation
Translation is the whole process by which the
base sequence of an mRNA is used to bring and
join amino acids in a polypeptide.
The three types of RNA participate in this
essential protein-synthesizing pathway in all
cells.
Translation
ATP
Adenosine triphosphate is a nucleotide that is
used in energetic reactions for temporary energy
storage.
Energy is stored in the phosphate bonds of ATP.
The cells use the energy stored in ATP by
breaking one of the phosphate bonds, producing
ADP.
ATP
ATP
ATP
Summary of Nucleic Acids
Monomer: nucleotide A, T (or U), C, G
Functional group(s): Phosphate Amino Hydroxyl
Polymer: DNA and RNA
Basic Nucleotide Structure
Summary of Nucleic Acids
Lipids
Fats, oils, waxes, and sterols are collectively known as lipids.
Fats contain only carbon, hydrogen, and oxygen.
Lipids
Are insoluble in water but soluble in nonpolar solvents.
Are also an important component of cell membranes.
Used for long-term energy storage. One gram of fat stores more than twice as
much energy as one gram of carbohydrate.
Lipids
Important classes of lipids:
1. Phospholipids
2. Steroids
3. Glycerides
4. Waxes
Phospholipids
Contain: Phosphate group on third -OH group of
glycerol. Two fatty acids.
Have a polar head, which increases hydrophilicity.
Phospholipids
Arrange themselves into double-layered membranes with the water-soluble phosphate ends on the outside and the fatty acid facing the inside.
Cell membranes are not rigid or stiff since phospholipids are in constant motion as they move with the surrounding water molecules and slide past one another.
Phospholipids
They also form spheroid structures called micelles.
Steroids
Have no fatty acid component. Contains a backbone of 4 carbon rings in 6-
6/6-5 arrangement. Examples:
Hormones Cholesterol Cell membrane components
Steroids
Steroids: Cholesterol
Cholesterol is a vital component of the cell membranes and used by cells to synthesize other steroids.
High cholesterol levels are associated with heart disease and the formation of plaques which obstruct blood vessels.
High blood levels of cholesterol bound to a carrier molecule called a low-density lipoprotein (LDL) are associated with the formation of the plaques in arteries.
Steroids: Cholesterol
Steroids: Cholesterol
Cholesterol bound to high-density lipoproteins tends to be metabolized or excreted and is often referred to as "good cholesterol".
Glycerides
Fats and oils are composed of fatty acids and glycerol.
Fatty acids have a long hydrocarbon chain with a carboxyl group.
The chains of fatty acids usually contain 16 to 18 carbons.
Fats are nonpolar and therefore they do not dissolve in water.
Glycerides
Fats are generally classified as esters of fatty acids and glycerol.
There can be one to three ester linkages of fatty acid chains to the glycerol, leading to the classification as:
1. Monoglycerides
2. Diglycerides
3. Triglycerides
Glycerides: Nomenclature
Fatty Acids
Structure:
Two classes:
1. Saturated
2. Unsaturated
Saturated Fatty Acids
Have no double bonds between the carbons in
its fatty acid chains.
Animal fats are more highly saturated than
vegetable fats.
Highly saturated fats are usually solid at room
temperature.
Unsaturated Fatty Acids
Also called “polyunsaturated fat”.
Contain at least one to several double bonds
between the carbons in its fatty acid chains.
Each double bonds produces a "bend" in the
molecule.
Molecules with many bends cannot be packed
as closely together, so these fats are less dense.
Unsaturated Fatty Acids
Usually these fatty acid are oils.
Most oils are of vegetable origin.
Triglycerides composed of unsaturated fatty
acids melt at lower temperatures than those with
saturated fatty acids.
Unsaturated Fatty Acids
Trans fat is the common name for a type of
unsaturated fat with trans-isomer fatty acids.
Most trans fats consumed today are created
industrially by partial hydrogenation of plant oils.
The goal of partial hydrogenation is to add hydrogen
atoms to cis-unsaturated fats, making them more
saturated.
Unsaturated Fatty Acids
These saturated fats have a higher melting point,
which makes them attractive for baking and extends
their shelf-life.
Trans fats are not essential in the diet and have
been linked with rises in levels of "bad" LDL
cholesterol and lowering levels of "good" HDL
cholesterol.
Saturated & Unsaturated Fatty Acids
Triglycerides
Are made up of a glycerol molecule with three fatty acid molecules attached to it.
Glycerol contains 3 carbons and 3 hydroxyl groups.
It reacts with 3 fatty acids to form a triglyceride or fat molecule.
The naturally occurring fatty acids always have an even number of carbon atoms.
Triglycerides
Waxes
Are composed of a long-chain fatty acid bonded to a long-chain alcohol
They form protective coverings for plants and animals (plant surface, animal ears).
Summary of Lipids
Monomer: Fatty acid Functional group(s):
Carboxyl Cholesterol Fused Rings Ester
Polymers: many – depending on the type of lipid Phospholipid, Steroid, Triglycerides, Waxes
Summary of Lipids
Summary of Biochemistry
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