| What is a glyosidic bond | - A condensation reaction between two monosaccharides |
| Monosaccharides | - One sugar |
| Disaccharides | - Two sugars |
| Polysaccharides | - Multiple sugars |
| What is a reducing sugar | - A sugar that can donate electrons to another molecule e.g. Benedict's reagent |
| Test for reducing sugars | - Food sample dissolved in water in test tube
- Equal volume of Benedict's reagent added
- Heated in water bath
- If it turns orange-brown sugar is present |
| What is a non-reducing sugar | - A sugar that cannot donate electrons to another molecule
- So it can't be detected with Benedict's reagent |
| Test for non-reducing sugars | - The non-reducing sugars must be broken down from disaccharides to monosaccharides
- Add dilute hydrochloric acid
- Heat in water bath
- Neutralise it with sodium hydrogen carbonate (Benedict's reagent will not work in acidic conditions)
- Heat it again with Benedict's reagent
- If sugar is present turns orange-brown |
| Examples of monosaccharides | - Glucose
- Galactose
- Fructose |
| Examples of disaccharides | - Maltose
- Lactose
- Sucrose |
| Examples of polysaccharides | - Starch
- Cellulose |
| What monomers make MALTOSE | - Glucose + glucose |
| What monomers make LACTOSE | - Glucose + galactose |
| What monomers make SUCROSE | - Glucose + fructose |
| Test for starch | - Add iodine
- Turns blue-black if present |
