• organic chemistry – the study of carbon compounds
• biochemistry – the stuyd of the chemistry of living species

• made of only hydrogen and carbon
• 4 types: alkanes, alkenes, alkynes, and aromatic hydrocarbons
• alkanes – only single bonds
• also called saturated hydrocarbons
• have the largest amount of hydrogen atoms bonded to a single carbon atom

• alkenes (olefins) – have double carbon bonds

• alkynes – triple carbon bonds

• aromatic hydrocarbons – carbon atoms connected in a planar ring structure, joined by s and p bonds between carbon atoms

• alkenes, alkynes and aromatic hydrocarbons – unsaturated hydrocarbons
• less volatile with increasing molar mass
• very low molecular weight = gas at room temperature
• moderate molecular weight = liquid
• high molecular weight = solid

1. Alkanes

• methane major part of natural gas
• used in home heating, gas stoves, hot-water heaters
• propane major part of bottled gas
• used for home heating, cooking
• butane – used in disposable lighters, fuel canisters
• alkanes with 5-12 carbon atoms are found in gasoline
• formla for alkanes is called condensed structural formulas

Lewis Structure

1. Structures of Alkanes

• tetrahedral geometry
• carbon-carbon single bond rotates easily at room temperature
• long chains tend to change shape

• straight-chained hydrocarbons – carbons atoms that are joined in a continuous chain
• branched-chain hydrocarbons – hydrocarbons with branched chains, 4 or more carbon atoms
• structural isomers – compounds with the same molecular formula but different bonding arrangements

• 1) Find the longest continuous chain of carbon atoms, and use the name of this chain as the base name of the compound.
• 2) Number the carbon atoms in the longest chain, beginning with the end of the chain that is nearest to a substituent
• 3) Name and give the location of each substituent group
• 4) When two or more substituents are present list them in alphabetical order

• alkanes that form rings or cycles
• carbon rings with fewer than five carbon atoms are strained
• more reactive

1. Reactions of Alkanes

• at room temperature alkanes do not react with acids, bases, or strong oxidizing agents
• important for it’s combustion in air; bases for fuels

2. Unsaturated Hyrocarbons
1. Alkenes

• double carbon bonds
• ethene or ethylene simplest alkene\
• nomenclature of alkenes come from the name of the corresponding alkane
• the –ane ending is changed to –ene
• geometrical isomers – compounds that have the same molecular formula and the same groups bonded to one another but differ in the spatial arrangement of these groups
• geometrical isomers have distinct physical properties and differ in chemical behavior
• the double carbon bond is resistant to twisting
• rotation about a double bond is a key process in the chemistry of vision

1. Alkynes

• one or more triple bonds
• simplest alkyne is acetylene
• highly reactive
• named by changing the alkane ending (-ane) to –yne

1. Addition Reactions of Alkenes and Alkynes

• addition reactions – a reactant is added to the two atoms that form the multiple bond
• hyrogenation – reaction between al alkene and H₂

• simplest is benzene
• stability comes from the stabilization of the p electrons through delocalization in the p orbitals
• represented by a hexagon with an inscribed circle
• substitution reactions – one atom of a molecule is removed and replaced by another atom or group of atoms

2. Functional Groups; Alcohols and Ethers

• functional group – site of reactivity in an organic molecule; controls how the molecule behaves or functions
• chemistry of an organic molecule is determined by the functional groups it contains

1. Alcohols (R-OH)

• alcohols – hydrocarbon derivatives in which one ore more hydrogens of a parent hydrocarbon have been replaced by a hydroxyle or alcohol functional group

1. Ethers (R-O-R’)

• ethers – two hyrocarbon groups are bonded to one oxygen
• formed from two molecules of alcohol by splitting out a molecule of water
• condensation reaction – reaction where water is split out from two substances
• used in solvents

2. Compounds with a Carbonyl Group

• carbon oxygen double bonds

1. Aldehydes and Ketones

• carbonyl group in aldehydes has at least one attached hydrogen atom

• carbonyl group in ketones occurs at the interior of a carbon chain

• prepared by oxidizing alcohols

1. Carboxylic Acids

• carboxylic acids contain carboxyl functional group (COOH)
• important for manufacturing of polymers
• produced by oxidation in which the OH group is attached to the CH₂

1. Esters

• carboxylic acids that undergo condensation with alcohols
• have pleasant odors
• saponification – hydrolysis of an ester in a base

1. Amines and Amides

• amines – organic bases; general formula R₃N
• amides – anines containing a hydrogen bonded to nitrogen that undergoes condensation

2. Introduction to Biochemistry

• biosphere – part of the earth where living organisms are formed and living
• includes influences on life of the atmosphere, natural waters, solid earth
• living organisms require a large amount of energy
• biopolymers – three categories: proteins, polysaccharides (carbohydrates), and nucleic acids

2. Proteins

• macromolecular substances
• 50% body’s dry weight is proteins
• composed of amino acids

1. Amino Acids

• differ in the R group
• building block of all proteins - a -amino acid
• general form:

• chiral - any molecule containing a carbon with four different attached groups
• enantiomers – mirror-image of chiral
• enantiomers and chiral have the same physical properties
• differ in chemical reactivity toward other chiral molecules

1. Polypeptides and Proteins

• peptide bond – condesation reaction between the carboxyl group of one amino acid and the amino group of another amino acid
• polypeptides – large number of amino acids that are linked together by peptide bonds
• proteins are polypeptide molecules
• weighs from 6000 to over 50 million amu

1. Protein Structure

• primary structure – arrangement of amino acids along a protein chain
• makes the protein unique
• secondary structure – the way segments of the protein chain are oriented in a regular pattern
• a -helix – most important and common secondary structure arrangement
• first propoesed by Linus Pauling and R. B. Corey
• tertiary structure – overal shape of a protein
• globular protein – a protein that folds into a compact spherical shape
• soluble in water, mobile within cells
• enzymes – large protein molecules that serve as catalysts

2. Carbohydrates

• written as C_x(H₂O)_y
• glucose the most abundant carbohydrate C₆H₁₂O₆
• not really hydrates of carbon but polyhydroxly aldehydes and ketones

1. Disaccharides

• monosaccharides – simple sugars that can’t be broken into smaller molecules by hydrolysis with aqueous acids
• disaccharide – two linked monosaccharides
• two common disaccharides: sucrose, lactose

1. Polysaccharides

• made of several monosaccharide units
• starch – group of polysaccharides
• food storage in plant seeds and tuers
• glycogen – starchlike substance synthesized in the body
• 5000 to more than 5 million amu
• energy bank in the body; muscles and liver
• cellulose – major strructural unit of plants
• straight chains of glucose units
• more than 500,000 amu

2. Nucleic Acid

• nucleic acids – biopolymers that are chemical carriers of an organisn’t genetic information
• deoxyribonucleic acids (DNA) – huge molecules with molar weights of 6-16million amu
• ribonucleic acids (RNA) – smaller molecules with molecular weights of 20,000 to 40,000 amu
• DNA found inside the nucleus of a cell, RNA found outside nucleus in the cytoplasm
• DNA stores the genetic information of the cell and controls the production of proteins
• RNA carries information from the DNA out of the nucleus
• Monomers of nucleic acids (nucleotides) have three parts:
• 1) A phosphoric acid molecule, H₃PO₄
• 2) A fice-carbon sugar
• 3) A nitrogen-containing organic base

• deoxyribose has one less oxygen atom at carbon 2 than ribose
• nucleic acids are polynucleotides
• DNA molecules made of two DNA chains that form a double helix

*molecular structures created from ChemSketch program*

*www.acdlabs.com*