CHAPTER 2 The Chemistry of Life

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CHAPTER 2 The Chemistry of Life
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2-1 WHATS THE MATTER?

• All of the materials around you are made up of
  matter. You are made up of matter, as are the
  chair you sit on and the air you breathe.
• 1. Give an example of solid matter.
• 2. Give an example of liquid matter.
• 3. Give an example of gaseous matter.
• 4. Is all matter visible?
• 5. Does all matter take up space?

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2-1 ATOMS

• Smallest building block of matter
• Subatomic Parts of an Atom
• Proton positively charged particle
• Location inside nucleus
• Mass 1 AMU (Atomic Mass Unit)
• Atomic Number of protons
• Can NOT change within an atom
• Electron negatively charged particle
• Location outside nucleus in orbitals
• Has no mass
• Number can change within an atom causing ions
• Neutron neutrally charged particle (no charge)
• Location inside nucleus
• Mass 1 AMU
• Number can change within an atom causing isotopes
• Atomic Mass of protons of neutrons

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2-1 ELEMENTS

• A pure substance that consists of only one type
  of atom
• It has unique chemical and physical properties
  different from all other elements
• There are over 100 known elements, but only about
  25 that are found in living organisms
• Elements You Should Know
• Carbon (C)
• Hydrogen (H)
• Oxygen (O)
• Nitrogen (N)
• Calcium (Ca)
• Sodium (Na)
• Iron (Fe)
• Phosphorus (P)
• Chlorine (Cl)
• Sulfur (S)

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2-1 THE PERIODIC TABLE

• C element symbol for Carbon
• 6 atomic number
• Carbon name of element
• 12.011 atomic mass

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C
Carbon
12.011
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2-1 Isotopes

• Atoms of the same element that have different
  numbers of neutrons
• Still have all the same chemical properties as
  the original element
• Identified by their mass numbers (see below)
• Radioactive Isotope nucleus is unstable and
  break down releasing radioactive energy which can
  be dangerous
• Important Uses
• Geology carbon dating
• Medicine treat cancers and kill bacteria
• Biology tracers to follow movements of
  substances within an organism (Barium Study)

Nonradioactive carbon-12
Nonradioactive carbon-13
Radioactive carbon-14
6 electrons 6 protons 6 neutrons
6 electrons 6 protons 8 neutrons
6 electrons 6 protons 7 neutrons
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2-1 CHEMICAL COMPOUNDS

• Compound substance formed by the chemical
  combination of 2 or more elements in definite
  proportions
• Physical chemical properties usually very
  different from original elements
• Ex. Na silvery metal that explodes on contact
  with water . Cl green
  poisonous gas
  . NaCl table
  salt
• Chemical Formula shorthand description of a
  compound
• ex. H2O - 2 hydrogen atoms, 1 oxygen atom
• ex. NaCl 1 sodium atom, 1 chlorine atom

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2-1 CHEMICAL BONDS

• Hold atoms together in a compound
• Valence Electrons electrons on the outermost
  orbit of an atom that are available to form bonds
• TYPES OF BONDS
• Ionic Bond 1 or more electrons are transferred
  from 1 atom to another
• Ions are formed with ionic bonds (ex. NaCl)
• Positive ion is the atom which has lost the
  electron(s) (ex. Na)
• Negative ion is the atom which has gained the
  electron(s)(ex. Cl-)

Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na)
Chloride ion (Cl-)
Transfer of electron
Protons 11 Electrons -11 Charge 0
Protons 17 Electrons -17 Charge 0
Protons 11 Electrons -10 Charge 1
Protons 17 Electrons -18 Charge -1
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2-1 CHEMICAL BONDS

• TYPES OF BONDS (cont.)
• Covalent Bond electrons are shared between
  atoms
• Molecules are formed with covalent bonds (ex.
  H2O)
• Single Bond 2 shared electrons
• Double Bond 4 shared electrons
• Triple Bond 6 shared electrons

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2-1 CHEMICAL BONDS

• TYPES OF BONDS (cont.)
• Van der Waals Forces a slight attraction formed
  between oppositely charged regions of nearby
  molecules
• Not as strong as ionic or covalent bonds

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2-2 THE WATER MOLECULE

• Most abundant compound on Earth
• Polarity an uneven distribution of electrons
  make the overall molecule have partial charges

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2-2 THE WATER MOLECULE

• Hydrogen Bonds attraction between partial
  charges not as strong as ionic or covalent bonds

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2-2 THE WATER MOLECULE

• TYPES OF HYDROGEN BONDS
• Cohesion attraction between molecules of the
  SAME substance
• Ex. Water extremely cohesive (surface tension)
• Adhesion attraction between molecules of
  DIFFERENT substances
• Ex. Water Glass (capillary action)

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2-2 ACIDS, BASES pH
Oven cleaner
Oven cleaner

• Water molecules can react to create ions
• H2O H OH-
• pH Scale based on the number of H
• Goes from 0 to 14
• pH 7 neutral (equal numbers of both ions)
• pH higher than 7 basic
• pH lower than 7 acidic
• Acids contain a higher concentration of H than
  water
• Bases (alkaline) contain a lower concentration
  of H than water
• Buffers weak acids or bases that can react with
  strong bases or acids to prevent sharp changes in
  pH

Bleach
Bleach
Ammonia solution
Ammonia solution
Soap
Increasingly Basic
Soap
Sea water
Sea water
Human blood
Human blood
Pure water
Neutral
Milk
Pure water
Milk
Normal rainfall
Normal rainfall
Acid rain
Acid rain
Tomato juice
Increasingly Acidic
Tomato juice
Lemon juice
Lemon juice
Stomach acid
Stomach acid
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2-2 SOLUTIONS SUSPENSIONS

• Mixture material composed of 2 or more elements
  or compounds that are physically mixed together,
  but not chemically combined (no chemical bonds)
• Ex. Earths atmosphere
• Gas/gas
• Gas/liquid
• Liquid/liquid
• Liquid/solid
• Solid/solid
• Solid/gas

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2-2 SOLUTIONS SUSPENSIONS

• TYPES OF MIXTURES
• Solutions a mixture whose components are evenly
  distributed
• Ions break away and are attracted to/ surrounded
  by polar forces Ex. Salt water
• Solute the substance that is dissolved
• Solvent the substance in which the solute is
  dissolved

Cl-
Cl-
Na
Na
Water
Water
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2-2 SOLUTIONS SUSPENSIONS

• TYPES OF MIXTURES (cont.)
• Suspensions mixtures of water and nondissolved
  materials
• Ex. blood

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2-3 CHEMISTRY OF CARBON

• The Chemistry of Carbon
• Have 4 valence electrons
• Forms strong covalent bonds with other atoms
• Can bond with many other elements H, O, P, S, N
• Can bond with other C atoms to form chains and
  rings
• ORGANIC COMPOUNDS all compounds that contain
  bonds between carbon atoms

Methane
Benzene
Isooctane
Acetylene
Butadiene
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2-3 MACROMOLECULES

• Macromolecules
• Monomers - small units that join together to form
  polymers (identical or different)
• Polymers molecule made up of many monomers
• Polymerization process in which monomers are
  joined together to form polymers
• Macromolecules large molecules formed by
  polymerization

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2-3 ORGANIC COMPOUNDS

• Carbohydrates
• Compounds made up of C, H, O in a 121 ratio
• Main source of energy for humans
• Plants also use them for structural purposes
• Monosaccharides simple sugar molecules
• Glucose, galactose, fructose
• Polysaccharides macromolecules formed from many
  monosaccharides
• Glycogen (animal starch)
• Starch and cellulose (plants)

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2-3 ORGANIC COMPOUNDS

• Lipids
• Contain C, H, O atoms and are commonly called
  fats, oils, waxes
• Used to store energy and are important parts of
  biological membranes
• Structure (see pg. 46)
• Saturated means contains the maximum number of H
  atoms (no double bonds)
• Unsaturated (polyunsaturated) means contain at
  least one double bond

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2-3 ORGANIC COMPOUNDS

• Nucleic Acids
• Contains C, H, O, N, P
• Made from monomer units called nucleotides
• 5 C sugar (ribose or deoxyribose)
• Phosphate group
• Nitrogenous base (A/T G/C)
• Store transmit hereditary genetic info
• Examples deoxyribonucleic acid (DNA) ribonucleic
  acid (RNA)

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2-3 ORGANIC COMPOUNDS

• Proteins
• Contain C, H, O, N
• Monomer units are called amino acids
• Amino group NH2
• Carboxyl group - -COOH
• More than 20 different amino acids
• Part of amino acid that is different is the
  R-group
• Control the rate of reactions regulate cell
  processes
• Form bones muscles
• Transport substances into or out of cells help
  fight disease
• Hemoglobin
• Molecule

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2-4 CHEMICAL REACTIONS ENZYMES

• Chemical Reactions
• A process that changes 1 set of chemicals into
  another set of chemicals
• Reactants elements or compounds that enter into
  a chemical reaction
• Products elements or compounds that are
  produced by a chemical reaction
• Chemical reactions always involve the breaking of
  bonds in reactants formation of new bonds in
  products
• Examples
• To lungs CO2 H2O ? H2CO3 (carbonic acid)
• In lungs H2CO3 ? CO2 H2O

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2-4 ENERGY IN REACTIONS

• Energy In Reactions
• Energy Changes
• Release often occur spontaneously
• Absorb will not occur without a source of
  energy
• Example
• 2 H2 O2 ? 2 H2O (energy releasing) heat,
  light, sound
• Activation Energy
• Reactions that release energy dont always occur
  spontaneously
• Energy needed to start a reaction is called
  activation energy

Energy-Releasing Reaction
Energy-Absorbing Reaction
Activation energy
Products
Activation energy
Reactants
Reactants
Products
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2-4 ENZYMES

• Enzymes
• Catalyst substance that speeds up the rate of a
  chemical reactions (lower activation energy)
• Enzymes are proteins that act as biological
  catalysts
• Speed up chemical reactions that take place in
  cells
• Enzyme Action
• Enzyme substrate complex
• Substrates are the reactants of enzyme catalyzed
  reactions
• Active site place where substrates bind to
  enzyme (lock key or puzzle pieces)
• Complex stays together until reaction is done
• Regulation of enzyme activity
• Enzymes are affected by many variables including
  pH and changes in temperature (37 degrees C)
• ENZYME ACTIVITY DEMO

Activation energy without enzyme
Reaction pathway without enzyme
Activation energy with enzyme
Reactants
Reaction pathway with enzyme
Products
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2-4 ENZYME ACTIVITY

• Enzyme
  (hexokinase)

Glucose
Substrates
ADP
Products
Glucose-6- phosphate
ATP
Products are released
Active site
Substrates bind to enzyme
Enzyme-substrate complex
Substrates are converted into products