Biological Molecules Flashcards
Reaction from monomer to polymer
Condensation reaction, a water molecule is produced and monomers are left covalently bonded.
Reaction from polymer to monomer.
Hydrolysis reaction, requires the addition of a water molecule which splits into OH and H to join with monomer and break their covalent bond
What are the 2 isomers of glucose
Alpha glucose
Beta glucose
What is an isomer?
Compound with the same formula but different atomic arrangement
What is the general formula for monosaccharides?
(CH2O)n
What is the difference between a monosaccharide, disaccharide and polysaccharide?
Mono= one chain of sugar
Di- two chains
Poly= many chains
What are reducing sugars?
Sugars that give up electrons to the reagent used in testing for sugars, causes a colour change
What is the test for reducing sugars?
Method
1. Crush food sample
2. Add distilled water
3. Add a similar volume of Benedict’s reagent
4. Put into a water bath to heat up
5. Positive result= colour change
Blue= none
Green/ yellow= traces
Orange= moderate amount
Brick red= large amounts
What is maltose?
2 glucose molecules bonded together (alpha glucose)
Found in food, natural
Cannot be absorbed into blood
What is sucrose?
1 glucose, 1 fructose bonded together
Bonded by a glycosidic bond between the two monosaccharides
What is lactose?
1 galactose and 1 glucose boned together
What are 5 examples of monosaccharides?
Glucose
Fructose
Galactose
Deoxyribose
Ribose
What is always released when two monosaccharides are bonded together?
H2O, water
What are non-reducing sugars?
Ones that dont really give up their electrons to reduce the copper sulphate in the Benedict’s solution
What is the test for non-reducing sugars?
- Add 2cm3 of your sample to a test tube with 10 drops of HCL
- Heat to boiling point for 2 mins (the acid causes the hydrolysis)
- Add sodium hydrogen carbonate spatula by spatula until the fizzing stops to neutralise the acid (Benedict’s doesn’t work under acidic carbonate)
Test with PH paper to confirm it is neutral/ slightly alkaline - Retest with Benedict’s to observe a colour change