as-u1-2.2 carbohydrates-monosaccharides
TRANSCRIPT
1. Sufferers of bowel cancer sometimes have to have part of their small intestines removed to prevent the cancer from spreading. Suggest one symptom a person may experience from this. Give a reason for your answer.
2. Antacids can be taken to treat indigestion. Antacids work by neutralising excess stomach acid. Suggest how taking antacids may have an effect on digestion.
Carbohydrates-Monosaccharides
Objective: To understand how carbohydrates are made up of simple units know as monosaccharides.
Outcomes:
~ Describe what a monosaccharide is and name examples. ~ Explain how to carry out a test for reducing sugars.
Keywords
MonomerPolymerMonosaccharideReducing sugarBenedict’s
Thursday 13 April 2023
Carbohydrates?
Main function in the body?Energy
Named examples?Starch, glucose, glycogen
What enzymes help to digest them? Carbohydrases e.g. amylase
Chemical elements? CarbonHydrogenOxygen
Monomers and polymers
Carbohydrates are polymers.
An individual molecule is a monomer in this case a sugar, monosaccharide.
Polysaccharide
Monosaccharides~ Sweet tasting, soluble substances.~ e.g. Glucose, C6H12O6
~ Fructose and galactose ~ respiration
Biochemical test• All monosaccharides and some disaccharides
are reducing sugars.Reduction reaction involves electrons being
gained. The reducing sugars donate electrons to another
chemical, copper (II) sulphate or Benedict’s solution.
Forming red precipitate of copper (I)oxide
Test for reducing sugars
Benedict’s Test
1. Add 2cm³ of food sample (in liquid form) to a test tube.2. Then add 2cm³ of Benedict’s Reagent. 3. Heat mixture in gentle boiling water bath for 5mins.
[Reducing sugar]
Colour of solution and precipitate
None Blue
Very low Green
Low Yellow
Medium Brown
High Red
Results
