AP Biology Chapter 5. Macromolecules

AP Biology Macromolecules  Smaller organic molecules join together to form larger molecules  macromolecules  4 major classes of macromolecules:  carbohydrates  lipids  proteins  nucleic acids

AP Biology Polymers  Long molecules built by linking chain of repeating smaller units  polymers  monomers = repeated small units  covalent bonds

AP Biology How to build a polymer  Condensation reaction  dehydration synthesis  joins monomers by “taking” H 2 O out  requires energy & enzymes

AP Biology How to break down a polymer  Hydrolysis  use H 2 O to break apart monomers  reverse of condensation reaction  H 2 O is split into H and OH

AP Biology Carbohydrates

AP Biology Carbohydrates  Carbohydrates are composed of C, H, O Function:  energy u energy storage  raw materials u structural materials  Monomer: sugars  ex: sugars & starches

AP Biology Simple & complex sugars  Monosaccharides  simple 1 monomer sugars  glucose  Disaccharides  2 monomers  sucrose  Polysaccharides  large polymers

AP Biology Polysaccharides  Function:  energy storage  starch (plants)  glycogen (animals)  building materials = structure  cellulose (plants)  chitin (arthropods & fungi)

AP Biology Lipids

AP Biology Lipids  Lipids are composed of C, H, O  long hydrocarbon chain  Diverse group  fats  phospholipids  steroids

AP Biology Fat  Triglycerol  3 fatty acids linked to glycerol

AP Biology Fats  Long HC chain  non-polar  hydrophobic  Function:  energy storage  cushion organs  insulates body

AP Biology Saturated fats  All C bonded to H  No C=C double bonds  long, straight chain  most animal fats  solid at room temp.

AP Biology Unsaturated fats  C=C double bonds in the fatty acids  plant & fish fats  vegetable oils  liquid at room temperature

AP Biology Phospholipids  Structure:  glycerol + 2 fatty acids + PO 4

AP Biology Phospholipids & cells  Phospholipids of cell membrane  double layer = bilayer  hydrophilic heads on outside  hydrophobic tails on inside  forms barrier between cell & external environment

AP Biology Steroids  ex: cholesterol, sex hormones cholesterol

AP Biology Cholesterol helps keep cell membranes fluid & flexible

AP Biology Proteins

AP Biology Proteins  Most structurally & functionally diverse group of biomolecules  Function:  involved in almost everything  enzymes  structure (keratin, collagen)  carriers & transport (membrane channels)  receptors & binding (defense)  contraction (actin & myosin)  signaling (hormones)  storage (bean seed proteins)

AP Biology Proteins  Structure:  monomer = amino acids  20 different amino acids  polymer = polypeptide  complex 3-D shape

AP Biology Amino acids  Structure:  central carbon  amino group  carboxyl group (acid)  R group (side chain)  variable group  confers unique chemical properties of the amino acid —N——N— H H H | —C— | C—OH || O R

AP Biology Protein structure & function hemoglobin  function depends on structure  3-D structure  twisted, folded, coiled into unique shape collagen pepsin

AP Biology Primary (1°) structure  Order of amino acids in chain  A long ribbon

AP Biology Secondary (2°) structure  “Local folding”  Hydrogen bonds between R groups   -helix (spiral)   -pleated sheet (pleats)

AP Biology Tertiary (3°) structure  “Whole molecule folding”  Hydrogen bonds

AP Biology Quaternary (4°) structure  Joins together more than 1 polypeptide chain  only then is it a functional protein hemoglobin collagen = skin & tendons

AP Biology Denature a protein  Disrupt 3° structure  pH  salt  temperature  unravel or denature protein  “change the shape, change the function”  Some proteins can return to their functional shape after denaturation, many cannot

AP Biology Chapter 5. Macromolecules: Nucleic Acids

AP Biology Nucleic Acids  Function:  store & transmit hereditary information  Examples:  RNA (ribonucleic acid)  DNA (deoxyribonucleic acid)  Structure:  monomers = nucleotides

AP Biology Nucleotides  3 parts  nitrogen base (C-N ring)  pentose sugar (5C)  ribose in RNA  deoxyribose in DNA  PO 4 group

AP Biology Types of nucleotides  2 types of nucleotides  different Nitrogen bases  purines  double ring N base  adenine (A)  guanine (G)  pyrimidines  single ring N base  cytosine (C)  thymine (T)  uracil (U)

AP Biology RNA & DNA  RNA  single nucleotide chain  Ribose sugar  A, U, C, G  DNA  double nucleotide chain  Deoxyribose sugar  A, T, C, G

AP Biology Macromolecule Summary  Carbohydrates  Monomers=monosaccharides  Polymers=polysaccharides  Used for energy, ex. Sugar  Lipids=fats=triglycerides  Monomers=glycerol + 3 fatty acids  Polymers=triglycerides  Used for energy, ex. Steroids, cell membranes

AP Biology Macromolecule Summary  Nucleic Acids  Monomers=nucleotides  Polymers=nucleic acids  Store genetic information, ex. DNA, RNA  Proteins  Monomers=amino acids  Polymers=polypeptides  Used for growth, transport, communication, ex. hair, nails, enzymes