Human Biology, 7e

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Chapter 2
Chemistry Of Life
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Why Chemistry?

• You should know how you work!
• You should know how additives affect you!
• You should know how toxins affect you!
• You should know what a toxin is!
• You should know why food feeds us!
• You should know why water is the most precious
  and amazing substance on earth and should be
  fiercely protected!

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Basic Chemistry

• Elements and Atoms
• Molecules and Compounds
• Water and Living Things
• Molecules of Life
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

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Elements and Atoms

• Matter Anything that takes up space.
• Element Substance composed of one type of atom.
• Atom Smallest unit of an element that retains
  the chemical and physical properties of that
  element

• Neutron atomic particle with one mass unit and
  no charge.
• Proton atomic particle with one mass unit and a
  positive charge.
• Electron atomic particle with a negative charge
  and no mass.

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Isotopes

• Isotopes are atoms of an element that have the
  same atomic number but differ in the number of
  neutrons.
• This changes the property of that element
  slightly.
• Isotopes are sometimes radioactive.
• Useful Isotopes
• Radioactive Carbon--Carbon Dating
• Radioactive Iodine--Thyroid Scans

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Molecules

• Molecule Chemical Unit formed when atoms bond.
• What is a bond?
• Ionic bond Stealing then Attraction
• Covalent bond Sharing
• Hydrogen bond Attraction

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Ionic Reactions

• Ionic reactions chemical joining of oppositely
  charged Ions.
• Ion Particles that carry a positive or negative
  charge.
• Examples of Ions
• Na, Cl-, K, PO43, Ca2, HCO3-

• Charge is all about the number of electrons!
• Atoms like to have
• 2 electrons in their inner most orbital
• 8 electrons in the next orbital.

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Ionic Bond

• Ionic Bonds are formed by the attraction between
  oppositely charged ions.
• Historically this has been described as
  stealing.
• Think about Chlorine trying to get that lone
  electron from Sodium all to itself!

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Covalent Bonds

• Covalent bonds are formed when the atoms that
  join actually share electrons.
• A single bond is formed when a pair is shared
• A double bond is formed when 2 pair are shared
• A triple bond is formed when 3 pair are shared

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WATER!!

• If you remember nothing else from this lecture or
  even this class REMEMBER WATER!!
• Water is the most amazing and incredible molecule
  on the face of this earth.
• Water is the ultimate source of life as we know
  it and should be protected fiercely and shared.
• Water will ultimately determine whether or not we
  as a human race survive.

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Hydrogen Bonds

• The Amazing Hydrogen Bond results from the
  partial charges generated by the 105 degree angle
  between the two hydrogen atoms on the water
  molecule.
• Hydrogen bond attraction of hydrogen with a
  partial positive charge to another molecule with
  a partial negative charge.
• This gives water the unique ability to be
  COLLIGATIVE, or all together now!

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Water is Polar

• Water is a polar molecule with differing charges
  on differing sides.
• This sets up a critical difference between
  molecules
• Hydrophobic--afraid of water
• Hydrophilic--love water

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Properties of Water

• 1. Water is Liquid at Room Temperature.
• StructureCharge
• ChargeHbond
• HbondCling
• Cling Life!
• Low Mr Molecules are usually gasses at RT.
• O2, Mr32gas
• H20, Mr18liquid!

• 2. Water is the Universal Solvent.
• Water dissolves polar molecules
• Water allows chemical reactions to occur
• Water establishes boundaries
• Remember Hydrophilic and Hydrophobic?

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Properties of Water

• 3. Water is Cohesive
• Water sticks to sides
• Water fills vessels
• Blood is 92 water!
• Water molecules cling, but also rearrange, this
  allows water to flow!
• Water suspends molecules evenly

• 4. The temperature of water rises and falls
  slowly
• This prevents sudden or dramatic changes!
• One calorie will raise 1g of water 1 degree C.
• This is over two times the amount of energy
  required for other covalent molecules!
• Protection and Buffer

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Properties of Water

• 5. Water has a high heat of Vaporization
• Water to steam requires a lot of energy
• This property helps moderate the earths
  temperature
• Life as we know it would not exist if we were all
  gasses!
• Sweat amazing Sweat

• 6. Frozen water is less dense than liquid water
• Lakes freeze from the top down
• Allows for ice activities
• Protects organisms in Lakes

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Water Dissociates

• Water, or H2O dissociates freely into two ions
• H Hydrogen Ion
• OH- Hydroxide Ion

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H, OH- Ions and pH

• H ions and OH- ions play a key role in
  determining the pH of a solution.
• Solutions with lots of H will be acidic.
• Solutions with lots of OH- will be basic.
• How molecules dissociate in water determines
  whether they add an H or an OH- to the solution.
• This determines the pH of the solution.

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Acids and Bases

• Acids have a low pH
• Acids have a high concentration of H
• Molecules that add H to a solution are Acids
• Examples of Acids
• Lemon Juice
• Vinegar
• Sharp or Sour taste

• Bases have a high pH
• Bases have a low concentration of H
• Molecules that add OH- to a solution are Bases
• Examples of Bases
• Ammonia
• Baking Soda
• Bitter taste, slippery feel

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pH

• pH the Power of Hydrogen!
• The number refers to the H--concentration of
  H ions.
• Example
• Acids with a pH of 2
• 1 x 10-2 moles/liter H

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pH

• Remember
• pH is essentially the H ions in solution.
• A pH 7 solution has 1 x 10-7 moles/L H
• A pH 1 solution has 1 x 10-1 moles/L H
• A pH 14 solution has 1 x 10-14 moles/L H

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Buffers

• What happens when pH goes up or down?
• If our blood pH changes too much we could die.
• Buffers help regulate pH.
• A buffer is a chemical or combination of
  chemicals that keep the pH of a solution within
  its normal limits.
• Buffers take up H and/or OH-

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Molecules of Life

• Organic Molecules are Molecules of Life.
• Organic Molecules all contain Carbon and
  Hydrogen.
• Examples of Organic Molecules
• Sugars
• Fats
• Protein
• Nucleic Acids (DNA)

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Organic Molecules

• Organic Molecules contain Carbon and Hydrogen.
• Carbon likes to have 4 bonds.
• Carbon can bond with Oxygen, Hydrogen and
  Nitrogen.
• Functional Groups create unlimited diversity
  using the same basic building blocks.

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Macromolecules

• Macromolecules are Built One step at a time.
• A Monomer, or single unit, is the step.
• Brick Brick Building
• Monomer Monomer Polymer
• Monomer single unit
• Polymer chain of units

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Carbohydrates

• Breads, Pasta, Sugar!
• Literally Hydrates of Carbon, or H2O of Carbon.
• Simple small molecules, monosaccharides,
  disaccharides, and other smaller molecules.
• Glucose, Fructose, Sucrose
• Complex large molecules, big complexes of sugars
  arranged using different angle bonds.
• Starch, Glycogen, Cellulose

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Building Macromolecules

• Monomer Monomer Polymer
• This building process is all about water.
• This process is call condensation, or dehydration
  synthesis.
• An OH from one monomer is joined to a H from
  another monomer to form a polymer H2O.

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Macromolecules

• Monomers are joined using a dehydration, or
  condensation reaction.
• Polymers are broken down using a hydrolysis
  reaction.
• Hydrolysis water breaking
• Polymer water monomer monomer

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Fats

• Fats provide the most energy per gram!
• Fats are basically compacted hydrocarbon ( C and
  H) structures with different functional
  modifications.
• Examples
• Fatty Acid
• Phospholipid
• Steriod

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Saturation

• Saturated Fatty Acids are full of Hydrogen
• SaturateFull
• Saturated Fatty Acids take up less space and are
  solid at room temperature!

• Unsaturated Fatty Acids are not full of Hydrogen
• C C double bonds make kinks in the legs.
• Unsaturated Fatty Acids take up lots of space and
  are liquid at room temp!

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Phospholipids

• Phospolipids are critical fats.
• These fats interact with water in a specific
  manner which allows membranes to form.
• The phospho-head group is polar, and hydrophilic,
  thus will interact with water.
• The fatty acid tails are hydrophobic, thus will
  run away from water.
• This creates a double membrane--which is
  essential for life!

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Steroids

• Steroids are composed of 4 carbon rings fused
  together.
• Cholesterol is a steroid--many hormones are made
  from cholesterol.
• Testosterone, Estrogen, Metabolism, Water
• Cholesterol is key to our health!
• Essential for Hormones, Cell Wall
• Linked to CV disease

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Proteins

• Proteins These are the workhorse molecules of
  life!
• Examples
• structural proteins --metabolism
• mechanical proteins --immunity
• signaling molecules --hormones
• gene regulation --nerve function

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Proteins

• Proteins are assembled one amino acid at a time.
• Amino Acid Amino Acid Protein
• Proteins have 4 structural levels
• Primary--Amino Acid sequence
• Secondary--Internal Structures caused by Hydrogen
  bonding
• Tertiary--How the whole protein folds up
• Quaternary--more than one AA chain together

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Nucleic Acids

• Nucleic Acids are composed of Nucleotides
• DNA and RNA are Nucleic Acids
• Monomer Monomer Polymer
• Nucleotide Nucleotide Nucleic Acid
• A Nucleic Acid is composed of 3 parts
• a 5 carbon sugar
• a Carbon-Nitrogen ring
• a Phosphate

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Nucleic Acids

• DNA holds all our genetic information.
• We will discuss DNA in more detail during our
  genetics section.
• ATP is a crucial nucleotide.
• ATP is our energy source.
• Our bodies are physically focused on making ATP
  and using ATP. Essentially, thats all we are
  about (strictly physiologically speaking of
  course)

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