Question

Name the monosaccharide which each of the given compounds give on hydrolysis?
(A) Sucrose
(B) Lactose
(C) Maltose
(D) Raffinose

Answer 1

Hint: To solve this question, first we need to understand that on hydrolysis, the polysaccharides break down to simpler forms like disaccharides and further to monosaccharides. So let’s start with the definition of each.

Complete answer:
Monosaccharides are the simplest type of carbohydrates and these monosaccharides join other monosaccharide units through glycosidic bonds to form disaccharides , oligosaccharides and polysaccharides.
Now, let’s solve our given options one by one.
So, coming to our first option i.e. Sucrose
Sucrose – it is commonly known as table sugar.
A sucrose is composed of monosaccharide Glucose and Fructose.
 $ Sucrose\xrightarrow{{Sucrase}}Glu\cos e + {\text{ Fructose}} $
When an enzyme sucrase acts on sucrose , it hydrolysed into glucose and fructose.
Coming to our next option i.e.
Lactose- it is a disaccharide .
Lactose splits up into Glucose and Galactose on hydrolysis.
 $ Lactose\xrightarrow{{Lactase}}Glu\cos e + {\text{ Galactose}} $
Maltose – It is also a disaccharide.
Maltose is composed of two units of Glucose , so on hydrolysis it yields two molecules of glucose. This hydrolysis reaction of maltose is acted upon by the enzyme Maltase.
Raffinose – It is a trisaccharide i.e. composed of three units of monosaccharides joined by the glycosidic bonds.
So, Raffinose on hydrolysis gives Glucose , Fructose and Galactose.
 $ Raffinose\xrightarrow{{Lactase}}Glu\cos e + {\text{ Galactose + Fructose}} $
So , above we have clearly understood the composition of each of the given carbohydrates and their products on the hydrolysis.

Note:
Disaccharides are the carbohydrates composed of two units of monosaccharides through glycosidic bonds .In oligosaccharides up to ten units of monosaccharides are joined together. Whereas, polysaccharides can be defined as the carbohydrate consisting of more than ten units of monosaccharides.