Biology AQA 3.1.2 Carbohydrate digestion

Food is taken into the mouth and chewed, this breaks in up causing a larger surface areaSaliva enters the mouth and mixes with these secretionsSaliva contains amylase which hydrolises starch in maltoseThese secretions enter the stomach, and the acid denatures the enzymesIt then goes to the small intestine where there is pancreatic juicesthe juice contains amylase and continues hydrolysing starch into maltoseThe epithlial lining contains maltase, this hydrolises maltose in glucose and glucose

Disaccharides:    Broken down by(enzyme):    Into:Maltose              Maltase                             Glucose and Glucosesucrose              Sucrase                            Fructose and glucoselactose               Lactase                           Glucose and galactose

Monomer: Single moleculePolymer: multiple molecules

A carbohydrate is a monosaccharide (monomer)

H     O    H! ......!.......!!               !HO        OH

Alpha Glucose HOH HOOH

Alpha Glucose is joined by glycosidic bonds (Monomer to polymer) during condensation to form maltose and starch

Lactose Intolerance:- Someone who doesn't produce enough lactase- leads to stomach problems and glucose and galactose isn't produced

Reducing Sugars: add food sample into testube- ensure it is in liquid form Add an equal volume of Benedicts reagent Heat the mixture in a water bath for 5 minutes compare to Benedicts scale

Blue Green Yellow Orange RedNone-Low-------------------------High

Non Reducing:If you do experiment up to stage 3 and the solution remains blue.5.create the solution again and add hydrochloric acid, place into water bath- this is done to hydrolyse the dissachride6.Add some hydrogen carbonate to neutralise PH (test with litmus paper)7. Re-test using Benedicts solution and following reducing sugar method.8. if sugar is present the colour will change.

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