Carbohydrates Flashcards
What are carbohydrates
Carbon molecules (carbo) combined with water (hydrate)
What is the name for a single monomer
Monosaccharide
What is a disaccharide
A pair of monosaccharides
What is a polysaccharide
Monosaccharides combined in larger numbers
What is the general formula for a monosaccharide
(CH2O)n where n is a number from 3 to 7
Eg glucose is a hexose sugar and will therefore have a formula of C6H12O6
What are examples of monosaccharides
Glucose
Galactose
Fructose
Draw alpha glucose
Answer on paper
Draw beta glucose
Answer on paper
Give examples of disaccharides and what monosaccharides make them
Alpha glucose + alpha glucose = maltose
Alpha glucose + fructose = sucrose
Alpha glucose + galactose = lactose
What is a condensation reaction
When monosaccharides join and a molecule of water is removed
What bond is formed during a condensation reaction
Glycosidic
What solution is used to test for reducing sugars
Benedict’s
How do you test for reducing sugars
1- if sample is not already liquid grind and add to water
2-add 2cm3 of the sample to be tested into a test tube with an equal volume of Benedict’s solution
3-heat mixture in a gentle boiling water bath for 5 minutes.if reducing sugars is present solution will turn brisk red
How do you test for non reducing sugars
1- if sample is not already liquid grid and add to water
2- add 2cm3 of the sample being tested to equal parts Benedict’s solution in a test tube
3- heat the mixture i a gently boiling water bath for 5 minutes if solution doesn’t change colour then a reducing sugar is not present
4-add another 2cm3 of your testing sample to 2cm3 hydrochloric acid in a test tube and heat in a gently boiling water bath for 5 minutes
5-remove from the water bath and add some sodium hydrogen carbonate to the test tube I order to neutralise the hydrochloric acid
6-retest the resulting solution by heating with 2cm3 Benedict’s solution and add to a gently boiling water bath for 5 minutes. If non-reducing sugar is present solution will turn brick red
Why are polysaccharides suitable for storage
They are very large and insoluble