Reactions that make and break polymers

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Unit 1 Cellular Energetics

• Part I Macromolecules
• Part II Enzymes
• Part III Cellular Respiration
• Part IV DNA Replication
• Part V Protein Synthesis

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Part I Macromolecules
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The questions

• What are monomers? What are polymers?
• How are polymers synthesized (built) and
  hydrolyzed (broken down)?

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Dehydration Synthesis (condensation)

• Reaction that joins molecules together by
  removing water
• Polymerization the synthesis of a polymer
• Polymers are built from monomers via dehydration
  synthesis

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Hydrolysis

• Breaks polymers into their constituent monomers
  (building blocks) by lysing (breaking) bonds
  through the addition of water.

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1. Carbohydrates (polysaccharides)

• Contain CHO
• General molecular formula CH2O
• Aldoses and Ketoses vary in location of carbonyl
  group -CO
• Aldoses have carbonyl on ends (glucose)
• Ketoses have carbonyl within molecule (fructose)

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Monomer monosaccharide
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Disaccharides (double sugars)

• 2 monosaccharides joined by a glycosidic linkage
• Covalent bond formed between two monosaccharides
  by dehydration synthesis

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Examples of disaccharides

• Maltose glucose glucose
• Sucrose glucose fructose
• Lactose glucose galactose

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Polysaccharides (many sugars)

• Long polymers of many monosaccharides
• Architecture function determined by position of
  glycosidic linkages
• Alpha linkages are breakable by Eukaryotes
• Starch, glycogen
• Beta linkages are NOT
• Cellulose, chitin

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Types of Polysaccharides

• A. Structural polysaccharides
• Beta glycosidic linkages
• Cellulose - plant cell walls, structural molecule
• Chitin - exoskeleton in insects, arachnids,
  crustaceans

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• B. Food storage molecules
• Alpha glycosidic linkages
• Starch- food storage molecules in plants
• Glycogen- food storage molecules in animals

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2. Lipids

• Group shares one common trait no affinity for
  water
• Do NOT consist of monomers ? polymers
• Highly varied group
• Biologically important
• Fats
• Phospholipids
• Steriods

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A. Fats

• Made of glycerol and 3 fatty acids
• Saturated fatty acids (animal fats) are carbon
  chains with single bonds only
• Ex Butter, lard solids at room temp.
• Unsaturated fatty acids (plant fats) have at
  least one double bond (kinks in chain)
• Monounsaturated only one double bond
• Polyunsaturated many double bonds
• Ex Vegetable oils liquid at room temp

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Hydrogenated fatty acids

• Hydrogen is artificially added to replace double
  bonds with single bonds.
• Liquids are solidified
• Ex peanut butter, margarine

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B. Phospholipids

• 2 fatty acids (tails) attached to phosphate group
  head

• When placed in water they self assemble into a
  micelle

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C. Steroids

• Lipids characterized by carbon skeletons
  consisting of four fused rings
• Ex. Cholesterol
• Common component of animal cell membranes (this
  is why animal meat is higher in cholesterol)
• Precursor from which other steroids, including
  sex hormones, are synthesized

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3. Proteins

• Most diverse of all macromolecules
• Humans have over twenty thousand proteins in
  their bodies, each performing a specific function

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General Categories of Proteins

• 1) Structural Spider silk
• 2) Storage Egg white
• 3) Transport Hemoglobin
• 4) Hormonal Insulin
• 5) Receptor Transport protein
• 6) Contractile Actin myosin
• 7) Defensive Antibodies
• 8) Enzymatic Digestive enzymes

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Monomers Amino Acids

• 20 total amino acids
• 8 essential AAs must be derived from food
• 12 can be synthesized by body
• THREE TYPES
• Non-polar (8)
• Polar (7)
• Electrically charged (acidic, basic) (5)

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General structure of amino acid

• All amino acids have a carboxyl group (-COOH) on
  one end and an amino group (NH3) on the other
• R group determines their interactions with one
  another to form secondary, tertiary, and
  quaternary structure

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Polymers polypeptides

• Formed by dehydration synthesis
• Peptide bonds bonds between adjacent amino acids

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Protein shape determines function

• Primary structure sequence of amino acids

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• Secondary Structure coiling or folding of
  polypeptide chain in repeated patterns
• Ex Alpha helices
• Ex Beta pleated sheets

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• Tertiary structure irregular contortions from
  interactions between side chains (R-groups) with
  one another
• H-bonds
• Disulfide bridges
• Hydrophobic interactions

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• Quaternary structure 2 or more polypeptide
  chains aggregated into 1 functional molecule

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4. Nucleic Acids

• Nucleic acids are the building blocks of both DNA
  and RNA
• DNA directs its own replication, transmits
  genetic information to future offspring, and
  controls RNA synthesis
• RNA controls protein synthesis

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Nucleotides
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Monomer Nucleotides

• Nucleotide - building block of nucleic acids
• Composed of three subunits
• 1) Pentose sugar (ribose or deoxyribose)
• 2) Phosphate groups comprise the
  sugar-phosphate backbone
• 3) Nitrogenous bases variable portions of the
  molecule

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DNA vs. RNA
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Polymer polynucleotide

• Adjacent nucleotides are joined by covalent bonds
  called phosphodiester linkages between the -OH on
  one nucleotide and the phosphate on the next
  nucleotide

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Complementary Base Pairing

• Always a Pyrimidine with a Purine
• Purines are Adenine Guanine
• Pyrimidines are Cytosine, Thymine (DNA only), and
  Uracil (RNA only)

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Complementary Base Pairing
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Why Do Bases Bond This Way?

• Hydrogen bonds
• A and T form two hydrogen bonds
• G and C form three hydrogen bonds
• Therefore, there is no way to bond inappropriately

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Base Pairing
T
A
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Base Pairing
C
G
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Macro Structure of DNA

• Double Helix- Twisted Ladder of A-T and G-C
  base pairing
• DNA contains genes (thousands) that code for
  proteins
• In association with proteins (histones) DNA makes
  chromosomes (46 in humans)
• Stored in nuclei of Eukaryotic cells