Chapter 5

Question 1

What are carbohydrates?

Answer 1

Carbohydrates are monomers and polymers of aldehydes and ketones that have numerous hydroxyl groups attached. They are the most abundant class of organic compounds, with a general formula of Cx(H20)y. This formula suggest that they are hydrates of carbons with very few exceptions.

They are classified into three groups:
Monosaccharides
Oligosaccharides
Polysaccharides

Question 2

What is a monosaccharide?

Answer 2

The simplest carbohydrate with a general formula of (CH2O)n, where n is the number of atoms between 3 to six. They cannot be hydrolized, and can further be divided into trioses, tetroses, pentoses, hexoses etc, which are categories based on the number of carbon atoms they contain. They are white crystalline solids and are reducing in nature.

The two most familiar monosaccharides and fructose and glucose, both which have a formula of C6H12O6. Some monosaccharides can rotate the plane of polarized light clockwise, these are called dexto-rotatory or dextrose sugars. Glucose and galactose are dextrose sugards.

Question 3

What is an oligosaccharide?

Answer 3

A category of hydrocarbons that forms 2 to 10 molecules of simple sugars upon hydrolysis. They are white crystalline solids that are soluble in water and have a sweet taste.

The exact number of molecules produced also further clarified as diasaccharides, trisaccharides etc; all starting with prefixes that indicate the number.

Question 4

What are Polysaccharides?

Answer 4

A category of carbohydrates that form hundreds and thousands of sugars upon hydrolysis. They are amorphous solids that tasteless and insoluble in water. Examples include starch and cellulose.

Question 5

List sources of carbohydrates.

Answer 5

Pg 93