SCH4U%20Unit%201%20Organic%20Chemistry

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SCH4UUnit 1 Organic Chemistry
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Organic Chemistry

• Definition the chemistry of carbon compounds
• Must contain carbon, may be in covalent
  combination with hydrogen, oxygen, nitrogen,
  sulfur or phosphorus
• Occurs in all living things, no life exists
  without carbon.
• Exception not all carbon containing compounds
  are considered organic. (carbonates and oxides)

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History of Organic Chemistry

• At the beginning of modern chemistry, all organic
  compounds were obtained from naturally occurring
  organic matter.
• Soaps were obtained from fats,
• Dyes and drugs from plants
• Henna from lawsonia shrub

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Evolution of Organic Chemistry

• 1828, synthesis the first organic compound urea
  from ammonia and cyanic acid began an enormous
  ongoing religious debate
• a synthesized compound has no difference in the
  chemical or physical properties of a naturally
  occurring compound.
• today organic is acquiring meaning that suggest
  mysterious vital forces. i.e.. organic food
  organic gardening organic vitamins

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The Amazing Carbon Atom

• Most unusual property of carbon is its ability to
  combine with itself this ability makes the
  number of potential organic compound nearly
  infinite
• 10 million organic compounds are already known,
  each with unique structures, names, chemical and
  physical properties.
• 95 of all known compounds are organic compounds
• Carbon always contains four covalent bonds,
  usually to hydrogen, sulfur, nitrogen, oxygen,
  halogens as well as other carbon atoms

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Organic Organization

• Chemists have organized organic compounds into
  families
• Each family consists of compounds of similar
  molecular structure and properties
• The largest family are the Hydrocarbons
• Hydrocarbon Family is divided into
• The Alkanes
• The Alkenes
• The Alkynes
• The Aromatics

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Naming Hydrocarbons
of Carbons 1 2 3 4 5 6 7 8 9 10
Prefix Meth Eth Prop But Pent Hex Hept Oct Non De
c
C-C ane ane ane ane ane ane ane ane ane ane
C C yne yne yne yne yne yne yne yne yne
CC ene ene ene ene ene ene ene ene ene
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The Alkane Family

• At room temperature, alkanes from 1 to 4 carbon
  atoms are gases. 5- 16 carbon atoms are liquids,
  17 or more are solids.
• Non-polar molecules, colourless, odourless
• Relatively inactive
• Most important property, burn producing a lot of
  heat mainly used as fuels.
• All hydrocarbons can undergo complete combustion
  into carbon dioxide and water

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Structure of Alkanes

• Each carbon contains four covalent bonds to four
  different atoms.
• Carbons are joined by single covalent bonds

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Methane

• Simplest alkane
• Main component of natural gas
• Contributing green house gas
• Used as fuel

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Ethane Propane

• Second most simple alkane
• Minor ingredient of natural gas

• Also known as bottled gas
• Found in natural gas, but separately for
  commercial purposes

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Butane

• Gas used in butane lighters
• Four carbon chain allows for different
  constitutional isomers.
• - Compounds which share the same molecular
  formula but differ in their structural formula
• Do you remember the difference between sec-butyl,
  isobutyl, tert-butyl or n-butyl groups?

Question 1 Can you draw 4-tert-butyl-4-isobut
yl-5-n-butyl-5-sec-butylnonane?
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Higher Alkanes

• Pentane, Hexane, Heptane, Octane, Nonane are all
  used to make gasoline
• Decane used to make kerosene
• All are derived from crude oil through a process
  called Cracking breaking longer chain
  hydrocarbons into smaller chains

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Alkenes

• Contain a double bond between two or more carbon
  atoms
• Considered unsaturated
• Non-polar, insoluble in water
• Chemically reactive
• Lighter alkenes are gases at room temperature
• Heavy alkenes are liquids or solids with low
  melting points

Name Formula B.P.
Methane CH4 -162
Ethane C2H6 -89
Propane C3H8 -42
Butane C4H10 -1
Pentane C5H12 36
Hexane C6H12 69
Heptane C7H14 98
Octane C8H16 126
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Properties of Alkenes continued

• Occur widely in nature, fruits and vegetables
  give off ethene which triggers further ripening
• Red colour of tomatoes is a result of lycopene, a
  hydrocarbon with many double bonds

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Ethene

• Simplest member if the alkene family, also called
  ethylene
• Most important commercial organic chemical
• U.S. production over 20 billion kg, more than
  have is used in the production of polyethylene,
  one of the most familiar plastics.

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Higher Level Alkenes

• Alkenes containing four carbons provide the
  opportunity for isomerization, a change in the
  location of the double bond.
• Different double bond positions result in
  different chemical properties.
• Question Why do we want to buy foods that have 0
  trans fats?
• Can you name these compounds?

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Alkynes

• Each alkyne molecule contains at least one triple
  bond between carbon atoms
• Unsaturated, reactive
• Non-polar, do not dissolve in water
• Burn in the presence of oxygen
• Gases liquids, or low melting solids at room
  temperature

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Ethyne

• Commercially known as acetylene
• Used as a fuel in welding torches
• Used in the past as a surgical anesthetic

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Higher Level Alkynes

• alkynes containing four carbons provide the
  opportunity for isomerization, a change in the
  location of the triple bond.
• Different triple bond positions result in
  different chemical properties

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Hydrocarbon Comparison
propane
propene
propyne
Boiling Point -42.1 C -47.8 C -23.2C
Melting Point -187.7 C -185.3 C -102.7C
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Aromatic Hydrocarbons

• All float on water, used mainly as solvents and
  fuels
• Vapours can act as narcotics when inhaled
• Benzene can cause leukemia with prolonged
  exposure
• Naphthalene is used an an insecticide (mothballs)

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Reactivity of the C-C Bond

• Relative reactivity
• Unsaturated C-C bonds increased reactivity
• Alkynes gt Alkenes gt Aromatics gt Alkanes

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Reactions of Hydrocarbons

• Possibly the most important reaction of
  hydrocarbons of low molar mass is that they burn
  in the presence of oxygen - Combustion
• liberates large amounts of energy as light and
  heat, making them invaluable as fuels
• Combustion of Octane

2 C8H18 25 O2 ? 18 H2O 16 CO2
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Reactions of Alkanes

• ALKANES Reactions with halogens to form alkyl
  halides or halocarbons halogenated alkane
• Substitution reaction
• Rule One H atom from the alkane is substituted
  for one halogen atom.  The H atom that is removed
  combines with the other atom of the halogen.

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Reactions of Alkanes

• Methane gas is heated with an excess of chlorine
  gas.
• CH4 Cl2 ? CH3Cl HCl
• Propane reacts with excess bromine
• C3H8 Br2 ? C3H7Br HBr
• Octane reacts with fluorine gas
• C8H18 F2 ? C8H17F HF
• Reactions with F2 are vigorous, but Cl2 and Br2
  require heat or UV light to dissociate the
  halogen molecule

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Reactions of Alkenes and Alkynes

• ALKENES/ALKYNES Additions across the double or
  triple bond
• Addition Reaction an atom is added to the
  molecule without the loss of hydrogen
• Undergo addition reactions with
• Halogens
• Hydrogen
• Hydrogen halides
• Water
• Rule The reactants are generally just added
  together

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Reactions of Alkenes and Alkynes

• Halogenation addition of an halogen (X2)
• Hydrogenation addition of hydrogen (H2)

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Reactions of Alkenes and Alkynes

• Hydrohalogenation addition of a hydrogen halide
• Hydration addition of water

?
H-Br
20oC
H2SO4
?

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Markovnikovs Rule

• This is an empirical rule based on Markovnikov's
  experimental observations on the addition of
  hydrogen halides to alkenes.
• "when an unsymmetrical alkene reacts with a
  hydrogen halide to give an alkyl halide, the
  hydrogen adds to the carbon of the alkene that
  has the greater number of hydrogen substituents,
  and the halogen to the carbon of the alkene with
  the fewer number of hydrogen substituents
• the rich get richer

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Markovnikovs Rule

• the rich get richer
• Mechanistic Info

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Reactions of Aromatic Hydrocarbons

• Aromatics are less reactive than alkenes due to
  resonance stability
• do not normally undergo addition reactions (only
  under extreme conditions)
• Substitution Reactions Hs on benzene ring more
  easily replaced than Hs on alkanes
• Benzene Br2 ? bromobenzene HBr
• Bromobenzene Br2 ? 1,3-dibromobenzene
• Benzene nitric acid (H2SO4)? nitrobenzene H2O
• Benzene ethyl chloride (AlCl3)? ethyl benzene
  HCl

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Functional Groups

• Functional groups are specific groups of atoms
  that exhibit characteristic properties when
  bonded to hydrocarbons
• The functional groups are
• Alcohols Carboxylic Acids
• Ethers Ketones
• Aldehydes Esters
• Amines

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Alcohols

• Alcohols have an OH group added on in place of a
  hydrogen
• Tend to be polar, dissolving in water
• Highly flammable, used as fuels, antiseptics,
  beverages and others

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Methanol

• important solvent
• possible replacement for gasoline
• Toxic methanol is oxidized in the body to
  formaldehyde
• 30 mL can cause blindness or death
• Smaller amounts result in nausea, convulsions,
  respiratory failure

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Ethanol

• Alcohol found in wine, liquor or beer
• Industrial ethanol made from ethene is cheaper
  because it generally lacks the same taxes on the
  recreational alcohol
• Although identical, industrial contains a noxious
  substance to prevent people from drinking it.
• A solution of 70 ethanol by volume acts as an
  antiseptic by coagulating bacterial proteins

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Isopropanol

• Commonly called rubbing alcohol
• Used to give sponge baths to reduce high fevers.
• Alcohol quickly evaporates removing heat from the
  skin surface, lowering ones temperature

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Propanetriol

• Commonly known as glycerol, or glycerin
• Very thick, sweet tasting compound
• Nontoxic, excellent carrier of medicine
• Used by cosmetic industry in hand and skin creams
  because it acts as a good lubricant

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Ethers

• Extremely flammable
• Anesthetic properties
• Diethyl ether most common
• ether to medical personal
• Used in long surgical procedures.
• Extremely safe anesthetic because there is a
  large difference in dosage between that needed to
  anesthetize and that needed to kill
• No longer used because of high flammability

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Aldehydes

• Formaldehyde is the simplest and best known
• When dissolved in water, it is used as a
  germicide, disinfectant, and preservative
• Used to preserve tissue

How do you make an aldehyde starting from an
alcohol? Do you need a primary, secondary or
tertiary alcohol?
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Ketones

• Propanone, also known as acetone is the simplest
  ketone
• Found in paint and nail polish removers
• Found in small amounts in the blood. Large
  amounts indicate diabetes mellitus
• This individual will have acetone smelling breath.

Do you remember how to make a ketone?
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Carboxylic Acids

• Simplest carboxylic acid is methanoic or formic
  acid
• Bee, wasp and hornet venom contains some formic
  acid
• Often have powerful, unpleasant odours
• Rancid butter
• Body odour

Butanoic acid
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Esters

• Quite fragrant even when dilute
• Many have fruity odours and tastes
• Used in flavourings for candies, as well as
  ingredients in perfume

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Amines

• Generally have a strong smell
• Produced when living organisms decay
• Cadavarine shown below is the compound
  responsible for the smell of rotting fish

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Applications of Hydrocarbons

• Carbon is able to form strong single, double and
  triple bonds with itself.
• This allows carbon to form long chains of atoms
  with a variety of geometrical shapes.
• Long chains called polymers are stable under
  standard conditions of temperature and pressure.

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POLYMERS Plastics, Nylons, and Food

• An Introduction to Polymers

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Polymers Greek for many parts

• Polymers are long molecules made up of many
  similar or identical building blocks linked by
  covalent bonds
• The word polymer is Greek for many parts
• Polymers include
• Synthetic
• Plastics
• Polyester, Nylon, Kevlar
• Teflon
• Natural
• Rubber
• Cotton (cellulose), Silk (proteins), Wool
  (cellulose)
• Proteins
• DNA

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Polymers

• Macro-molecule consisting of repeating monomer
  subunits
• include every type of plastic, all proteins, DNA,
  cotton, silk, wool, etc.
• first synthetic plastic, celluloid, was made from
  pyroxylin as part of a contest to produce an
  ivory substitute for billiard balls

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Synthetic Polymers

• Polymers are molecules made up of repeating
  molecules called monomers.
• The properties of the monomer affects the
  properties of the polymer
• One of the simplest polymers is polyethylene
• This polymer is synthesized through an addition
  reaction of ethene molecules
• ?

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Polyethylene

• most important polymer
• used in plastic bags, bottles, straws etc.
• made from joining ethene monomers into a
  repeating saturated polyethylene molecule
• forms a thermoplastic material, which can be
  softened by heat and remolded into various forms

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Two Forms of Polyethylene

• Low Density Polyethylene
• molecules are more randomly distributed ,
  resulting in a semi-rigid, translucent plastic,
  resistant to many chemicals, and has a high
  degree of flexibility
• used in electrical wire insulation, plastic bags,
  bottles

• High-Density Polyethylene
• forms a highly ordered arrangement, resulting in
  a rigid material
• used to make toys, bottle caps, plumbing pipes

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Polyethylene

• There are two types of PE
• LDPE
• HDPE
• LDPE
• The chains have a high degree of branching. The
  chains therefore do not pack well. Therefore it
  has less intermolecular forces. The branching
  allows the plastic to serve in diverse types of
  applications
• Ex. Grocery bags, wire insulation, containers
• HDPE
• The chains have a low degree of branching. The
  chains can therefore pack closely, adding to the
  intermolecular forces.
• Ex. Containers for milk, water and juice, garbage
  containers, toys

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Polystyrene

• colour and filler is added to make inexpensive
  toys, household items, throw away drinking cups
• gas can be blown into polystyrene liquid
  resulting in a foam which hardens into Styrofoam
• used as insulation, packaging material, coffee
  cups

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Polyvinyl Chloride

• Tough synthetic material
• Vast properties including
• Clear rigid material
• Long-lasting floor covering
• Lightweight, rustproof plumbing

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Teflon

• Non-stick coating
• All hydrogen atoms in ethylene are replaced by
  fluorine
• Polymerization produces polytetrafluoroethylene
  (PTFE), or Teflon
• C-F bonds are exceptionally strong, heat and
  chemical resistant, unreactive and non-flammable

Can you draw tetrafluoroethylene? How do you
think two of these molecules link together?
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Rubber

• Natural rubber is obtained from various tropical
  plants
• monomer from which rubber is composed is called
  isoprene
• natural rubber not very useful sticky in warm
  weather, hard and brittle in cold weather

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Vulcanization

• Discovered by Charles Goodyear, rubber took on
  more favorable properties over a wider range of
  temperatures when heated in the presence of
  sulfur
• vulcanization allows chains of rubber to
  cross-link
• the number of crosslinks between the strands of
  rubber determine how stretchy, or hard the rubber
  will be

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Other Synthetic Polymers

• Synthetic polymers can be made with cross
  linking, as in the case of Kevlar.
• This enhances strength
• Nylon is a polymer made to mimic the properties
  of silk protein
• It is synthesized through the reaction of
  hexanedioic acid (adipic acid) and
  1,6-hexanediamine (hexamethylene diamine)

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Natural Polymers

• These include
• Proteins
• Polyamides made up of 20 different amino acids
• Starch and cellulose
• Polysaccharides composed of sugar monomers
• Nucleic acids
• Backbone of alternating sugar and phosphate
  group. Monomer of nucleotides

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Proteins

• Amino acids contain two functional groups
• An amine group and a carboxylic acid group
• There are 20 different natural occurring amino
  acids. -Can you name them?
• There are 9 essential amino acids that must be
  ingested as they are not synthesized by the body
• Amino acid

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20 Amino Acids
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• Proteins are formed when an amine of one amino
  acid reacts with the carboxylic acid of another
  amino acid
• This bond formed is called a peptide bond
• The polymer is called a polypeptide

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Proteins and Chirality

• A chiral carbon is a carbon with 4 different
  attached groups.
• It exists as two different isomers. These
  isomers are mirror images of each other.
• This chirality plays a key role in biological
  systems.
• Often these isomers
• cause different effects
• in the body.

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Thalidomide

• This was a drug used in late 1957- the early 60s
  to treat pregnant women for morning sickness.
• One isomer reacts as an effective sedative.
• The other isomer is tetragenic
• Caused fetuses to develop abnormally.
• Resulting in deformation of limbs.
• The medication administered was a combination of
  both isomers.

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Levels of Protein Structure

• There are 4 levels of protein structure 1º, 2º,
  3º, 4º
• Primary the sequence of amino acids in the
  polypeptide chain
• Secondary the arrangements of the polypeptide
  chain caused by van der Waals forces
• a-helix, ß-sheets
• Tertiary the unique 3D arrangement of a unit
• Stabilized by other interactions covalent bonds,
  hydrogen bonds
• Quaternary protein subunits join through
  intermolecular forces forming one functional
  protein

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• Diagram of Levels of Protein Structure

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Starch and Cellulose

• These are carbohydrate polymers composed of sugar
  monomers
• They are called polysaccharides
• Plants are an excellent source of carbohydrates
• All carbohydrates have the empirical formula
  Cx(H2O)y
• Glucose, the sugar made from photosynthesis has
  the formula C6(H2O)6 or C6H12O6
• 5-C and 6-C sugars are generally in a ring
  structure.

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Starch and Cellulose

• 5-C and 6-C sugars are generally in a ring
  structure.
• When two of these sugars bond, they form
  disaccharides.
• ex. Maltose is a disaccharide of glucose

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Starch and Cellulose

• Starch and cellulose are both polymers of
  glucose.
• However the glucose-glucose linkages are
  different.

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Nucleic Acids

• The genetic information for all living things
• Two types of nucleic acids DNA RNA
• DNA deoxyribonucleic acid
• RNA ribonucleic acid
• Nucleic acids are polymers of nucleotides
• Nucleotides have 3 components
• Phosphate group (PO43-)
• Nitrogenous base (adenine, thymine, guanine,
  cytosine, uracil)
• Sugar (ribose or deoxyribose)

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The repeating chain is of phosphate groups
followed by sugars where the nitrogenous base is
bonded to the sugar.

• -

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DNA

• DNA is coiled into two strands forming a helical
  structure.
• The two strands are complimentary
• The two strands are held together by hydrogen
  bonding between NH groups and CO groups
• DNA is used by cells to code for proteins

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Assignment

• Handout Ch.2 Project
• Read 2.7
• Pg. 136
• Practice 4, 6
• Section Questions 1, 11
• Chapter 2 Review
• Pg. 146-147
• 7, 10, 11a, 16, 19, 20