Carbohydrat Biochemistry

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Carbohydrat Biochemistry

• AULANNIAM
• BIOCHEMISTRY LABORATORY
• BRAWIJAYA UNIVERSITY

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Carbohydrates

• Natures most abundant organic substance.
• Precursors for synthesis of all organic compounds
  in plants and animals
• Composed of C, H, and O atoms
• Contain Carbon , Hydrogen and Oxygen in the ratio
  of 121

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Carbohydrates

• Monomers are called monosaccharides.
• Carbohydrate polymers are known as
  polysaccharides.

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Macromolecular Structure

• Monomer
• Single unit of a macromolecule
• Can be linked together to form polymers

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CLASSIFICATION OF CARBOHYDRATES

• Monosaccharides
• Oligosaccharides
• Polysaccharides

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• Carbohydrates (cont.)
• Monosaccharides
• Simple sugars
• Monomer unit of carbohydrate group
• Examples Glucose, fructose
• Disaccharides
• Composed of two monosaccharide units joined
  together
• Examples Sucrose, lactose
• Polysaccharides
• Composed of multiple monosaccharide units (100s
  1000s)
• Examples Starch, glycogen, cellulose

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MONOSACCHARIDES

• Polyhydroxy aldehydes or ketones which cannot be
  further hydrolysed to simpler sugars
• Contain 3 to 10 carbon atoms, 2 or more
  hydroxyl(OH) groups and one aldehyde (CHO) or one
  ketone (CO) group

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Monosacharides

• If n3, triose (glyceraldehyde)
• If n5, pentose (fructose, ribose)
• If n6, hexose (glucose, galactose)
• Used for Energy and Building Blocks

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Monosaccharides

• Are also known as simple sugars.
• Glucose, for example, looks like this

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Simple Sugars

• The most important simple sugars are glucose,
  galactose, and fructose.

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Monosaccharides (simple sugars)

• all have the formula C6 H12 O6
• all have a single ring structure
• (glucose is an example)

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Simple sugars

• Generally made of carbon chains containing 4
  (tetrose), 5 (pentose), and 6 (hexose) carbons.
• Can be drawn as a straight chain, cyclic
  compound, or a chair configuration.

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Isomerism

• They can exist as isomers
• ? ? glucose

OH
?
?
OH
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Disaccharides

• Two sugars bonded together with the removal of a
  water molecule.
• Other common double sugars are sucrose (glucose
  and fructose) and lactose (glucose and galactose).

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Disaccharides (double sugars)

• all have the formula C12 H22 O11
• sucrose (table sugar) is an example

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Disaccharides

• Formed from two monosaccharides
• Joined by a glycosidic bond
• A condensation reaction
• glucose glucose ? maltose
• glucose galactose ? lactose
• glucose fructose ? sucrose

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Dehydration Synthesis

• Combining simple molecules to form a more complex
  one with the removal of water
• ex. monosaccharide monosaccharide ----gt
  disaccharide water
• (C6H12O6 C6H12O6 ----gt C12H22O11 H2O
• Polysaccharides are formed from repeated
  dehydration syntheses of water
• They are the stored extra sugars known as starch

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Hydrolysis

• Addition of WATER to a compound to SPLIT it into
  smaller subunits
• (also called chemical digestion)
• ex. disaccharide H2O ---gt monosaccharide
  monosaccharide
• C12 H22 O11 H2 O ---gt C6 H12 O6 C6 H12 O6

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OLIGOSACCHARIDES

• Sugars which yield 2 to 10 monosaccharide
  molecules on hydrolysis
• The monosaccharides are linked by glycosidic
  bonds
• Eg Maltose, Lactose and Sucrose

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POLYSACCHARIDES

• Non sugars giving more than 10 monosaccharide
  molecules on hydrolysis
• High molecular weight
• Form colloidal substances when heated with water
• Several monosaccharide molecules combine to form
  polysaccharides by glycosidic linkages

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CARBOHYDRATES - FUNCTIONS

• Structural component of cells
• Major source of energy
• Regulation of fat metabolism
• Osmotic and ionic regulation

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Polysaccharides

• Formed of three or more simple sugar units
• Glycogen - animal starch stored in liver
  muscles
• Cellulose - indigestible in humans - forms cell
  walls
• Starches - used as energy storage

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Polysaccharides

• Made of many simple sugars linked in chains
  called polymers.
• Examples of polymers are
• Starch common food storage in plants and food
  for animals
• Glycogen storage form of sugar in animals
• Cellulose main structural carbohydrate in plants

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Bioorganic Compounds

• Carbohydrates
• Composed mostly of carbon, hydrogen, and oxygen
• Large number of OH groups attached to the
  carbons
• Functions
• Energy source for living cells
• Certain structural components of cells

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Polysaccharides

• Polymers formed from many monosaccharides
• Three important examples
• Starch
• Glycogen
• Cellulose

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Polysaccharides

• Polymers of several monosaccharides
• Examples include
• Starch used by cells for energy (starch is like
  a battery).
• Cellulose used by plant cells for structure
  (cellulose is like microscopic chicken wire).
• Starch looks like this

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Dehydration Synthesis

• Dehydration (aka a condensation reaction) loses
  water from the polymer and links monomers
  together.
• Energy is stored in the resulting bond.

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Starch

• Amylose
• ?-glucose
• 1,4 glycosidic bonds
• Spiral structure

• Amylopectin
• ?-glucose
• 1,4 and some 1,6 glycosidic bonds
• Branched structure

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Glycogen

• Insoluble compact store of glucose in animals
• ?-glucose units
• 1,4 and 1,6 glycosidic bonds
• Branched structure

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Cellulose

• Structural polysaccharide in plants
• ?-glucose
• 1,4 glycosidic bonds
• H-bonds link adjacent chains

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FUNCTIONS OF POLYSACCHARIDES

• a number of monosaccharides joined together eg.
  Starch, a polymer of glucose, with formula
  (C6H10O5)n eg. Glycogen, same molecular
  formula--gives glucose when hydrolised, stored in
  liver and muscles as a reserve of carbohydrates.

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From monomers to polymers
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Hydrolysis

• Hydrolysis adds water to the chemical bond
  linking macromolecules.
• This results in the breakdown of the polymer and
  the release of energy.

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Cellulose
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Cellulose products
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Secondary metabolites

• Produced in small amounts
• Can be very complex (chemically)

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Why do plants produce secondary metabolites?

• Attractants

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Why do plants produce secondary metabolites?

• Deter predators

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Secondary metabolites as chemoprotectants

• Saponins and fungal resistance
• avenicin

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Cotton produces gossypol

• trichomes

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Phytoecdysones promote molting
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Thank you!