Sugars ~ 3.1.2 Flashcards Preview

Biology ~ A Level ~ AQA > Sugars ~ 3.1.2 > Flashcards

Flashcards in Sugars ~ 3.1.2 Deck (10):
1

What are monosaccharides?

The simplest sugars, the building blocks of carbohydrates.

2

What do carbohydrates contain?

Carbon
Hydrogen
Oxygen

3

What is glucose?

A hexose sugar. There are two types of glucose:
~ alpha (α)
~ beta (β)
The two types of glucose have the H and OH groups reversed.

4

What is a disaccharide made of?

Two monosaccharides joined together.

5

How are disaccharides formed?

Monosaccharides are joined together by condensation reactions ~ a glycosidic bond forms between the two monosaccharides as a molecule of water is released.

6

What is the bond in a disaccharide?

Glycosidic

7

What is sucrose?

A disaccharide formed from a condensation reaction between glucose and fructose.

8

What is lactose?

A disaccharide formed from a glucose molecule and a galactose molecule.

9

What is the Benedict's test for reducing sugars?

~ Add Benedict's reagent (which is blue) to a sample
~ Add heat in a water bath
~ If reducing sugars are present the sample forms brick red precipitate (or green or yellow or orange)

10

What is the Benedict's test for non reducing sugars?

~ if the result for reducing sugar is negative there could still be non reducing sugars present
~ you break them into monosaccharides
~ you do this by getting a new sample of test solution, adding dilute hydrochloric acid
~ carefully heat in a water bath
~ neutralise it by adding sodium hydrogencarbonate
~ carry out the Benedict's test you would for reducing sugar