Biology AQA 3.1.2 Carbohydrate digestion

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Food is taken into the mouth and chewed, this breaks in up causing a larger surface area

Saliva enters the mouth and mixes with these secretions

Saliva contains amylase which hydrolises starch in maltose

These secretions enter the stomach, and the acid denatures the enzymes

It then goes to the small intestine where there is pancreatic juices

the juice contains amylase and continues hydrolysing starch into maltose

The epithlial lining contains maltase, this hydrolises maltose in glucose and glucose

Disaccharides: Broken down by(enzyme): Into:

Maltose Maltase Glucose and Glucose

sucrose Sucrase Fructose and glucose

lactose Lactase Glucose and galactose

Monomer: Single molecule

Polymer: 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 Red

None-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 dissachride

6.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.

Content

Test