CHEMISTRY

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CHEMISTRY

• THE STUDY OF INTERACTIONS OF ATOMS MOLECULES

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MATTER

• Stuff of the universe
• Occupies space has mass
• Exists in different states
• Solid (e.g. bones)
• Liquid (e.g. blood)
• Gas (e.g. the air we breathe)
• Composed of Elements

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ENERGY

• Capacity to do work or move matter
• Exists in various forms, such as
• Chemical (stored in bonds)
• Electrical (movement of charged particles)
• Can change forms some is always lost as heat

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Glucose
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ELEMENTS

• ELEMENT
• Simplest chemical substance with unique chemical
  properties
• 92 in nature
• 24 in humans
• 4 most common in humans (96 body weight)
  Hydrogen, Oxygen, Carbon, Nitrogen
• Atoms are building blocks of elements

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ATOMS

• Smallest unit of element that retains the
  chemical characteristics of that element
• Smallest unit in chemical reactions
• Smallest structural unit in our bodies
• Composed of subatomic particles that differ in
• Mass
• Charge
• Position

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Subatomic Particles

• Proton
• Positive charge
• Weighs one atomic mass unit (amu)
• Located in atomic nucleus
• Neutron
• No charge 1 amu nucleus
• Electron
• Negative charge
• No significant weight
• orbits around nucleus

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ATOMIC STRUCTURE

• Nucleus
• Inner core
• Tightly bound protons neutrons
• Positively charged
• Electron Cloud
• Outer region
• Orbiting electrons (in orbitals, shells, clouds)
• Negatively charged
• The overall charge of the atom is neutral the
  protrons electrons

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Electron Cloud

• Electrons in orbitals (shells, clouds)
• Inner orbital full with 2 electrons
• Second orbital holds up to 8
• Third orbital also needs 8 for stability (holds
  up to 18)
• Valence outermost orbital with any electrons

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Atoms Electron Shells
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Atomic Structure Determines Atomic Function

• The number of valence electrons affects atomic
  reactivity
• Stable if valence (i.e. outermost occupied
  orbital) is full
• Reactive/unstable if incomplete valence
• Atoms can
• Gain/lose/share electrons
• Lose excess neutrons (Isotopes)
• Protons are NEVER lost or gained

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Atomic Characteristics of Elements Differ

• Atomic number
• Number of protons in atom
• Differs for each element
• Atomic weight (mass number)
• Sum of proton neutrons
• Atomic symbol
• The letter(s) used to represent atoms of the same
  element

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CHEMICAL BONDS

• Join atoms by valence electrons
• Result in molecules, compounds
• Electrons gained, lost or shared to fill valence
  (or reach stability)
• 3 Types
• Ionic or Electrovalent
• Covalent
• Hydrogen

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CHEMICAL BONDS continued

• IONIC BONDS
• Transfer of electrons between atoms
• Atoms that GAIN electrons have a net negative
  charge (anion)
• Atoms that LOSE electrons have a net positive
  charge (cation)
• Oppositely charged ions are mutually attractive
• Common in the formation of salts (e.g. sodium
  chloride, NaCl)

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CHEMICAL BONDS continued

• COVALENT BONDS
• Electrons shared between atoms
• Results in polar or nonpolar molecules
• Nonpolar if electrons shared equally OR even
  distribution of charge
• Polar if electrons not shared equally uneven
  distribution of charge
• Polar molecules align themselves with other polar
  molecules or charged particles
• Common in organic molecules

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Covalent Bonding
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Covalent Bonds in Water
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CHEMICAL BONDS continued

• COVALENT BONDS
• Electrons shared between atoms
• Results in polar or nonpolar molecules
• Nonpolar if electrons shared equally OR even
  distribution of charge
• Polar if electrons not shared equally uneven
  distribution of charge
• Polar molecules align themselves with other polar
  molecules or charged particles
• Common in organic molecules

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Polar Nonpolar Covalent Bonding
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CHEMICAL BONDS continued

• Chemical bonds represent STORED ENERGY
• Energy is required to form bonds
• Energy is released when bonds are broken
• Bonds may be formed or broken or both in a
  chemical reaction
• Most chemical reactions are reversible

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CHEMICAL BONDS continued

• HYDROGEN BONDS
• Form weak attraction within or between polar
  molecules
• Easily broken by Temp or pH
• Found in Proteins, Nucleic Acids, other large
  organic molecules between water molecules

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Hydrogen Bonding
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CHEMICAL REACTIONS

• SYNTHESIS
• A B ? AB
• Form bond, requires energy
• Dehydration Synthesis
• Water released as bond formed
• E.g. Glycogen from glucose

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Glycogen is a polymer of Glucose
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Dehydration Synthesis
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CHEMICAL REACTIONS continued

• DECOMPOSITION
• AB ? A B
• Breaks bonds, releases energy
• Hydrolysis
• Reverse of dehydration synthesis
• Water used to help break bonds
• E.g. Digestion of proteins into amino acids

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Hydrolysis
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CHEMICAL REACTIONS continued

• EXCHANGE
• AB C ? AC B
• Involves synthesis decomposition
• Bonds broken formed
• E.g. Glucose ATP ? Glucose phosphate ADP

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INORGANIC COMPOUNDS

• Dont contain both carbon and hydrogen
• Usually small, simple molecules
• Inorganic compounds common in cells
• Water
• Oxygen Carbon dioxide
• Salts
• Acids Bases

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INORGANIC COMPOUNDS continued

• Water
• Most common inorganic in human body
• Solvent (things dissolve easily in water)
• Participates in some reactions
• Absorbs releases heat slowly
• Lubricates cushions

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INORGANIC COMPOUNDS continued

• Salts
• Ionic compounds, dissolve in water
• Source of ions ? electrolytes
• Contribute to hardness of bones teeth
• Involved in blood clotting, muscle nerve
  physiology
• E.g. KCl (potassium chloride) and CaCO3 (calcium
  carbonate)

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• pH Scale
• Measures H in solution
• Log scale (ten-fold change between numbers)
• 0 to 14, 7.0 is neutral
• lt7 is acidic
• gt7 is basic/alkaline

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INORGANIC COMPOUNDS continued

• Acids Bases
• Acid
• Releases hydrogen ions (H) in water
• pH lt 7.0
• Strong acids completely dissociate in water
• Base
• Releases hydroxyl ions (OH-) in water
• pH gt 7.0

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Dissociation
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• Buffers
• Resist changes in pH
• Pick-up H or OH-, keep pH of solution relatively
  stable
• E.g. carbonic acid (H2CO3) from CO2 H2O

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ORGANIC COMPOUNDS

• Involve covalent bonds
• Made by dehydration synthesis
• Broken down by hydrolysis
• Contain carbon and hydrogen
• Include
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids

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ORGANIC COMPOUNDS continued

• Carbohydrates
• (CH20)n
• Built of monosaccharide(s)
• Sugars starches
• Major source of energy for making ATP (esp.
  glucose)

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Glucose
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CARBOHYDRATES continued

• Monosaccharides
• Simple sugars
• Ribose, Glucose, Fructose, etc
• Disaccharides
• 2 monosaccharides joined by dehydration synthesis
• sucrose
• Polysaccharides
• Long chain monosaccharides (complex carbs)
• Glycogen is a polymer of glucose

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Glycogen
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ORGANIC COMPOUNDS continued

• Lipids
• Composed of Fatty Acids Glycerol
• Source of maximum energy long-term energy
  storage
• Dont dissolve in water dissolve in fats
• Basic structure of cell membrane
• Includes triglycerides, phospholipids steroids

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ORGANIC COMPOUNDS continued

• Proteins
• Built of Amino acids
• 20 common amino acids in humans
• Most abundant organic compound
• Fibrous or globular in shape
• Complex 3D shape held together by hydrogen bonds
• Changes in temp or pH can disrupt hydrogen bonds,
  unfold protein with loss of function

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Amino Acid Structure
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Peptide Bond Formation
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PROTEINS continued

• Complex, 3-D shape determines function
• Primary Level order of amino acids in
  polypeptide
• Secondary Level twisting folding of chain,
  held by hydrogen bonds
• Tertiary Level 3 Dimensional shape, determines
  function
• Quaternary Level multiple polypeptide chains

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Hemoglobin
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ENZYMES

• Protein
• Increase rate of reaction (catalyst)
• Hold substrates in proper position to interact
• Substrates bind at active site
• Enzyme remains unchanged
• Different reactions require different enzymes
• Function best at optimal pH temperature

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ORGANIC COMPOUNDS continued

• Nucleic Acids
• Built of Nucleotides
• Sugar (Ribose or Deoxyribose)
• Phosphate group
• Nitrogenous Base
• Adenine
• Guanine
• Thymine (DNA)
• Cytosine
• Uracil (RNA)

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NUCLEIC ACIDS continued

• DNA Deoxyribonucleic Acid
• Deoxyribose (sugar)
• Thymine (NOT uracil)
• Double-stranded helix
• Phosphate group sugar form backbone
• Nitrogenous bases form complementary pairs (A-T,
  C-G)
• Bases joined by hydrogen bonds form rungs
• Code for Protein Structure

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DNA
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NUCLEIC ACIDS continued

• RNA Ribonucleic Acid
• Ribose (sugar)
• Uracil (NOT thymine)
• Single-stranded
• Carries out DNAs instructions for Protein
  Synthesis
• Includes
• mRNA
• rRNA
• tRNA

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Nucleic Acids RNA and DNA
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ATP - Modified Nucleotide

• Adenosine Triphosphate
• Nucleotide with 3 phosphate groups
• 2 high energy bonds
• ATP ? ADP P Energy
• Source of chemical energy used by all body cells
• Glucose most common source of energy to make ATP

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The Structure of ATP