1.2 - Carbohydrates - Monosaccharides

Question 1

Benedict’s test

Answer 1

• add 2cm^3 of the food sample to be tested, if not liquid form, grind it and filter in water
• add an equal volume of Benedict’s
• Heat the mixture gently for 5 mins in a water bath
• if positive a orange-brown colour is formed

Question 2

What’s benedicts reagent and when heated what does it form?

Answer 2

An alkaline solution of Cu(II) SO4 and when heated it forms a red precipitate of copper(I) oxide

Question 3

What are examples of reducing sugars and what therefore is a reducing sugar?

Answer 3

• All monosaccharides and some disaccharides are reducing sugars and a reduction is a chemical reaction which involves the gain of electrons or H2
• a reducing sugar is therefore a sugar that can check electrons to reduce another chemical

Question 4

Difference between alpha and beta glucose structure

Answer 4

Question 5

How many isomers does glucose have and what are they?

Answer 5

alpha or beta glucose

Question 6

examples of monosaccharides

Answer 6

galactose

fructose

glucose (c6h12o6)

Question 7

General formula of monosaccharides

Answer 7

(CH2O)n and n ranges from 3 - 7

Question 8

Properties of monosaccharides

Answer 8

Sweet-tasting

Soluble

Question 9

How do Polysaccharides get formed from a monomer?

Answer 9

A sugar (saccharide) are paired and forms a disaccharide and this forms large polysaccharides in large numbers

Question 10

What are carbohydrates?

Answer 10

Carbon molecules combined with water