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					Molecules of Life

    Chapter 3
                    Outline
• Molecules and life
• Water
• Carbon based molecules
  – Hydrocarbons
  – Carbohydrates
  – Lipids
  – Proteins
  – Nucleic acids
Water
           Water properties
• Unique properties based on its structure
• Oxygen is more electronegative than
  hydrogen
• Electrons spend more time with oxygen
  than with hydrogen
• Polar covalent bond
  – ie unequal sharing
                    Water properties
  • Unique properties based on its polarity
  • Oxygen more electronegative than hydrogen results in
    unequal sharing of electron


Slight polar ends
Polarity of Water causes
       “stickiness”
          Water Structure




Water molecules “stick” to each other in distinct patterns
resulting in organization of molecules
     Why is polarity important?
• Polarity causes molecules to interact in
  unique ways that influence life
• Encourages formation of hydrogen bonds
    Effects of Polarity on Water’s
              Properties
• Cohesion & Adhesion
• Capillary action
  – Interaction of cohesion & adhesion in small
    spaces
• Moderation of temperature
  – High specific heat
  – High heat of vaporization
• Density properties
• Solvent properties
                  Cohesion
• Water molecules
  tendency to “stick” to
  each other
• Forms hydrogen
  bonds in 3-d
• Results in surface
  tension
     Surface Tension




Why is surface tension important…
     Surface Tension in Biology




“Jesus Lizard”
http://www.visionlearning.com/library/module_viewer.php?mid=57
Surface Tension in Biology
             Surfactants
• Molecules that disrupt cohesion amongst
  water molecules
                    Surfactants




Don’t wash your car in the creek or dump soap down the storm wash!
                  Adhesion
• Water molecules
  tendency to “stick” to
  other polar molecules
Cohesion & Adhesion

                      Adhesion




    Cohesion
  Capillary Action
Cohesion & Adhesion
Capillary Action
Water Transport
              Terminology
• Heat= amount of
  energy associated
  with the movement of
  atoms and molecules
  in matter
• Temperature=
  measures the
  intensity of heat
        High specific heat
• H bonds retard motion at atomic level
• Water High specific heat
   – Stabilize temperatures
       » Keeps your body temperature stabilized
       » Keeps environmental temperature stabilized
     High heat of vaporization
– Relatively large amount of Energy removed when
  changing water from liquid to gas form
– Lots of Energy required to break H bonds
– Important in an organisms ability to moderate its
  temperature
   • Evaporative cooling
         Evaporative Cooling
• Aids in homeostasis   Heat
  maintenance
   Physical properties of water
• Density
  – Density increases as temp decreases
  – Water max density 4 degrees C
  – Molecules move apart
• Solvent properties
  – Protects ions from one another
  – Charged substances dissolve
  – Universal solvent
      Density




ice    water    steam
Density




 Ice floats!
Nutrient Cycling
Solvent
Water soluble protein
 Summary of Water’s Properties

• Cohesion & Adhesion
• Capillary action
  – Interaction of cohesion & adhesion in small
    spaces
• Moderation of temperature
  – High specific heat
  – High heat of vaporization
• Density properties
• Solvent properties
      Interactions with Water
• Hydrophillic
  – Polar or charged
• Hydrophobic
  – nonpolar
Hydrophobic
Hydrophillic
    General Molecule Structure
• Monomers
• Polymers
• Macromolecules
        Molecule Formation
• Dehydration synthesis
  – Connection of monomers through covalent
    bond that yields water
• Hydrolysis
  – Disassembly of polymer into component
    monomers with the use of water molecule to
    break covalent bonds
Molecule Formation
Chemical composition of human
            body
        Organic Molecules
• Why is carbon so important?
• Large, complex, diverse molecules
• Abundance of carbon based molecules
                 Carbon
• Reactive
• Covalent bonds
• Carbon branches (backbones)
Carbon Branching
Forms many Types of Molecules
Carbon Molecules have Complex
           Shapes




   In Biology Shape Maters!!
      Carbon Based Molecules
•   Hydrocarbons
•   Carbohydrates
•   Lipids
•   Proteins
•   Nucleic Acids
               Hydrocarbons
• Simplest compounds
• Only 2 elements
  – Carbon
  – Hydrogen
• Different numbers of each element
  – Ex. Methane CH4
• Unique shape
  – Shape matters
• Physiological importance
  – Energy rich
Hydrocarbons
What happens when we add different
types of elements to hydrocarbons?
          Functional Groups
• Groups of atoms that participate in chemical
  reactions
• Influence nature of molecule
• Characteristic of carbon molecule types
    Carbohydrate Characteristics
•   Sugar molecules
•   Energy sources
•   Hydrophyllic
•   Structure
    – 1:2:1 ratio CH2O
    – Monomers or polymers
      • Monosaccharides
      • Disaccharides
      • Polysaccharides
       Carbohydrate Types
• Monosaccharides
• Disaccharides
• Polysaccharides
          Monosaccharides
• Simple sugars
• Basic building blocks for organic
  molecules
• Primary cellular energy
• CH2O
• Ex. Glucose & fructose C6H12O6
Monosaccharides are rings
Glucose
Glucose vs fructose
Isomers
             Disaccharides
• 2 monosaccharides
• Formed via dehydration
• Examples
  – Sucrose= glucose + fructose
    • Plant sap
  – Maltose= 2 glucose
  – Lactose= glucase + galactose
Disaccharides
Sucrose
           Polysaccharides
• Aka complex carbohydrates
• Polymers of monosaccharides (3+)
• Examples
  – Starch
  – Glycogen
  – Cellulose
  – Hydrophyllic
Polysaccarhides
cellulose
                    Lipids
• Most with no polar regions= hydrophobic
  (insoluble)
• Triglycerides
  – Fats, waxes, oils
  – Glycerol & 3 fatty acids
• Phospholipids
• Steroids
Lipids




         3 fatty acids
            Biological functions
• Flavor foods
• Slow digestion
• Excellent energy source
    – 2X E of Carbs or proteins
•   Protective
•   Insulation
•   Cell membranes
•   Minimizes evaporation
•   Basis of hormones
    – Ex cholesterol
               Fats vs Oils
• Fat
  – solid at room temperature
• Oils
  – liquid at room temperature
• Hydrogenation= solid
               Types of Fats
• Saturated
• H atoms at all sites
• Ex. Lard, butter, solid
  fats
             Types of fats
• Unsaturated
  – Lacking one H atom
• Ex. Olive oil, nuts, avocado
         Health implications
• Saturated fats
  – Animal fats
  – Max # of H atoms ie no double bonds=
    parallel arrays
• Unsaturated fats
  – Veggie oils
  – 1+ double bonds = kinks
Saturated fat diet
                   Waxes
• Coat leaves, fruits, skin, feathers, fur, ears
• 1 fatty acid connected with alcohol
• +++++ hydrophobic
      Phospholipid Membrane
• Provides structure
• Regulation ie control
                  Steroids
• Hydrophobic
• Cholesterol fundamental unit
  – Cell membranes
• Base steroid
  – Sex hormones
  – Anabolic steroids
Steroids
Small difference amongst
molecules can result in big
       differences




     Testosterone   Estrodiol
                  Protein
• Polymers-
  macromolecules
• Complex 3D structure
                Protein Types
•   Support
•   Storage
•   Motion
•   Transport
•   Defense
•   Signal
•   Enzymes
Support
Storage
Motion
Transport
               Defense
• antibodies
Signal
                       Enzymes
• Catalysts
   – Lower the energy involved
     in chemical reactions
   – Speed up chemical
     reactions
   – Based on shape
   – Specific to a reaction
• Help chemical reactions
  occur
Enzyme function
                           Protein
• Structure of amino acids
  –   Carbon backbone
  –   Carboxyl group
  –   Amino group
  –   Hydrogen
  –   R group aka “side”
       • Polar, nonpolar
• 20 types of amino acids
• form peptide bonds via dehdration synthesis=
  polypeptide
Amino acids
Peptide bond
Building complex protein shapes is
           like origami
              Protein shape
•   Primary structure
•   Secondary structure
•   Tertiary structure
•   Quarternary structure
           Primary structure
•   Based on sequence of amino acid
•   Unique primary sequence
•   Unique # of aa and sequence
•   Infinite variety
Primary structure
        Secondary structure
• Turns and folds in chain of polypeptide
• Result of carbon backbone
• Allows H bonds to form and cause twisting
Secondary structure
          Tertiary structure
• 3D shape- irregular loops and folds
• Interactions among R groups
  – ionic bonds
  – Polar= h bonds
  – Covalent bonds
Tertiary structure
        Quarternary structure
• Multiple polypeptides
  join to form a protein
          Sickle cell disease
• Changes in the sequence of amino acid
• Can cause changes in 3D
                 Denaturation
• Unraveling and loss of normal protein
  shape
• Caused by
  – Temperature
  – PH
  – Change in aqueous environment
  – Mutation
     • Ex sickle cell
               Nucleic acids
•   Information storage molecules
•   Directions for building proteins
•   Found in nuclei of eukaryotes
•   Two forms
    – Deoxyribonucleic acid
    – Ribonucleic acid
• Polymers of nucleotides
                    Nucleotide
• 5 Carbon sugar
   – Deoxyribose
   – ribose
• Phosphate group
   – Po4-
• Nitrogenous base
   –   Accepts H+
   –   Adenine
   –   Guanine
   –   Cytosine
   –   Thymine
   –   Uracil
• Form polynucleotides aka dna strand
Nucleotide structure
Vary according to nitrogenous base




         DNA Nitrogenous Bases
Sugar phosphate backbone
            Double helix
• Complementary base pair rule
• A-T
• C-G
rna
      Different Bases




      Different Sugar