Chapter 5a: The Structure and Function of Macromolecules (Carbohydrates)

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Chapter 5aThe Structure andFunction
ofMacromolecules(Carbohydrates)
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Important Point
If you are having trouble understanding lecture
material Try reading your text before
attending lectures. And take the time to read it
well!
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Polymers / Monomers

• Many macromolecules consist of polymers
• A polymer is a large molecule built up from
  smaller building block molecules
• Monomers (a.k.a., subunits) are the building
  block molecules
• The inherent differences between human siblings
  reflect variations in polymers, particularly DNA
  and proteins. Molecular differences between
  unrelated individuals are more extensive, and
  between species greater still . . . The molecular
  logic of life is simple but elegant Small
  molecules common to all organisms are ordered
  into unique macromolecules . . . For each class
  (of compound) we will see that the macromolecules
  have emergent properties not found in their
  individual monomers.

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Polymers, Monomers, and Lipids

• Lipid monomers are less persistent than the above
  monomers
• Consequently, lipids are less-readily described
  using the same polymeric terms

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Dehydration (Polymer) Synthesis
Energy

• A.K.A., condensation reaction, dehydration
  reaction

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HydrolysisPolymer Breakdown

• Enzymes are employed in biological systems to
  effect most hydrolysis reactions

Energy
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Some Monosaccharides
Hence Carbo (C) Hydrate (H2O)
Note Basic Formula (CH2O)n
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Some Monosaccharides
All carbons in a monosaccharide are bonded to a
hydroxyl group (-OH) except for one which is
bonded to a carbonyl group  (O) (note that this
statement is true only for the linear form of
monosaccharides)
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Some Monosaccharides
Note Numerous Chiral Carbons
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Stable Monosaccharide Rings
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Linear Models in Quasi 3D
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Ring Forms (Glucose)
These are all Glucose
Memorize this structure
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?-D-Glucose
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Stable Monosaccharide Rings
And learn the numbers, too ?
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Closing the Ring
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Disaccharide Synthesis
Energy
The reactions, the names of the sugars, and
whether they are mono- or disaccharides is what
you should know (also, Glycosidic linkage)
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Amylose / Maltose / Glucose
Glucose is the most common monosaccharide
Note that saccharide has two cs!
A sugar polymer
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Starches
carbon and energy (glucose) storage molecules
more branching
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Starch/Glycogen
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Glucose Anomers
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Cellulose
Know the difference
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Cellulose
Cellulose is a Structural polysaccharide
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Cellulose
Most organisms cannot digest (hydrolyze)
cellulose
Organisms that can digest cellulose include the
microorganisms living the gastrointestinal tract
of many organisms typified especially by cows and
termites and many fungi (i.e., the things that
eat the wood of fallen trees)
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Cotton
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Chitin
Chitin is another example of a structural
carbohydrate. Chitin is found in the exoskeletons
of insects, spiders, and crustaceans. Chitin is
also found in the cell walls of fungi. Chitin is
leathery in pure form but is hardened in most
uses via the deposition of calcium carbonate.
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The End