Biol 1 - Carbohydrates

Biolgy Unit 1 AS Aqa Notes on Carbohydrates

  • Created by: Stephanie
  • Created on: 10-05-12 20:18


  • All contain C, H and O
  • Monomers = Monosaccharides
  • Polymers = Polysaccharides

Glucose Structure

  • Hexose sugar (six carbons)
  • Two forms; - Alpha (OH on C1 is down)
                      - Beta (OH on C2 is up - beta'up) 
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  • Condensation reactions (molecule of water lost)
  • Hydrolysis reactions breakdown
  • Bond is a 'glycosidic' bond

Breakdown of Dissachardies:

  • Maltose hydrolysed by Maltase -> Glucose + Glucose
  • Sucrose hydrolysed by Sucrase -> Glucose + Fructose
  • Lactose hydrolysed by Lactase -> Glucose + Galactose

Lactose Intolerance:

  • Not enough Lactase to breakdown Lactose
  • Undigested so not absorbed and fermented by bactera causing intestinal complaints (diorrhaoea)
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Benedicts Test

For Reducing sugars

  • Add blue benedicts reagent to solution and heat
  • If reducing sugars are present it turns red
  • Polysaccharides have to be broken down first;
    -by boiling with dilute HCL and neutralizing with Sodium hydrocarbonate 
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  • Made from polysaccharides Amylose & Amylopectin
    -long chains of Alpha Glucose
  • Main Carbohydrate store in plants

Starch Digestion:

  • Amylase = Starch -> Maltose
  • Maltase (released from intestinal epithelial cells) = Maltose -> Glucose
  • These enzymes work by hydrolysis reactions which break glycosidic bonds

Iodine Test (Test for Starch):

  • Add Potassium Iodide Solution to sample
  • If it turns black there is Starch
  • Otherwise stays orange 
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The voice over is really fast and doesn't read it as it should be read :/



luna wrote:

The voice over is really fast and doesn't read it as it should be read :/

That's not me its get revising's program that turns notes into speech that is poor =

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