The Structure and Function of Macromolecules

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The Structure and Function of Macromolecules

• Chapter 5
• Part I Carbos Lipids
• Part II Proteins Nucleic Acids

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Theme Structure Vs. Function

• Polymer long molecule of many identical or
  similar building blocks linked by covalent bonds.
• Monomers The repeating units of polymers small.

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Polymers and Monomers
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Building a Polymer

• Condensation or Dehydration Reaction

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Digesting a Polymer

• Hydrolysis (Hydro Water, Lysis to break)

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Variety

• Only 40 to 50 common monomers
• Vast number of polymers
• Small molecules common to all organisms are
  ordered into unique macromolecules.
• 26 letters in the alphabet vast of words
• 20 amino acids vast of proteins

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Carbohydrates

• Fuel and building materials
• Monosaccharide C6H12O6 Glucose, Fructose,
  Galactose
• Dissacharide Two monosaccharides, C12H22O11,
  Sucrose, Maltose, Lactose
• Polysaccharides 3 or more monosaccharides,
  Starch, Cellulose, Chitin, Glycogen

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Linear and Ring Forms
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• Hydroxyl Groups
• Carbonyl Group
• In liquid solutions, sugars form rings
• Major nutrients for cells
  (cellular respiration)
• Their carbon skeletons are used to make other
  types of organic molecules, including amino acids
  and fatty acids
• Two monosaccharides are joined by a glycosidic
  linkage

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Polysaccharides

• Storage and structural roles
• Starch a storage polysacch. of plants, joined
  by 1-4 linkages, these linkages make the molecule
  helical
• Starch stored in plant organelles called plastids
• By making starch, the plant can stockpile surplus
  energy.
• Humans and most animals have enzymes that can
  hydrolyze plant starch
• Wheat, corn, rice, and other grasses major
  sources of starch in the human diet

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Animals

• Store glycogen, a more highly branched polymer of
  glucose
• Store in liver and muscle cells
• In humans, the glycogen bank is depleted in about
  a day unless it is replenished by food

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Structural Polysaccharides

• Cellulose cell walls of plants most abundant
  organic compound on Earth
• There are two forms of glucose polymers called
  alpha and beta forms
• When the sugar rings form alpha polymers have
  their OH group, on the number one carbon facing
  below the ring, while beta versions have their
  OH group above the ring This difference makes
  cellulose indigestible to humans

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Chitin contains nitrogen

• Exoskeleton of insects
• Used to make surgical thread that decomposes
  after the wound heals

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Lipids Hydrophobic Molecules
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Lipids

• Do not contain polymers
• Grouped because hydrophobic
• Store large amounts of energy
• Oils, fats, phospholipids, waxes and steroids

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Saturated and Unsaturated Fatty Acids
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Purpose of Fat?
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Phospholipids

• Only two fatty acids. The third hydroxyl group
  of glycerol is joined to a phosphate group, which
  is negative in electrical charge.
• Both hydrophobic and hydrophilic
• When placed in water, phospholipids cluster into
  a micelle
• Cell membranes bi-layer

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Steroids

• Lipids characterized by a carbon skeleton
  consisting of four fused rings
• Cholesterol component of animal cell membranes,
  and precursor to other steroids
• Sex hormones