Problem 155 - A Complete Resource Book in Chemistry for JEE Main

Question

The number of monosaccharide molecules formed during hydrolysis from one mole of raffinose is

Step-by-Step Solution

Answer

3 moles of monosaccharide molecules.

Step 1: Understanding Hydrolysis of Raffinose

Raffinose is a trisaccharide composed of three monosaccharide units. During hydrolysis, raffunose is broken down into its constituent monosaccharide components.

Step 2: Identify Constituent Monosaccharides

Raffinose consists of one molecule each of glucose, fructose, and galactose. We need to determine how many monosaccharide molecules one mole of raffinose will yield after complete hydrolysis.

Step 3: Calculating the Number of Monosaccharides

Since one molecule of raffinose is composed of three different monosaccharides (glucose, fructose, and galactose), hydrolysis of one mole of raffinose will produce three moles of monosaccharides.

Key Concepts

Trisaccharides

Trisaccharides are a type of carbohydrate composed of three monosaccharide units linked together by glycosidic bonds. In simple terms, they are sugars that consist of three smaller sugar units.
These bonds connect the individual sugar molecules and can be broken through a process called hydrolysis. Hydrolysis involves the addition of water to break down complex molecules into simpler ones.
Trisaccharides, due to being composed of multiple sugar units, often have diverse roles in biological systems, from energy storage to being involved in various cellular processes.

• Examples include raffinose, maltotriose, and raffinose series of sugars.
• They are less sweet compared to monosaccharides because of their complex structure.
• Upon hydrolysis, they yield multiple monosaccharide molecules, depending on their structure.

Understanding how trisaccharides break down during hydrolysis can help in the study of metabolism and nutrition, as well as in industrial applications like food processing and biofuels.

Raffinose

Raffinose is a common example of a trisaccharide. It is found naturally in beans, whole grains, vegetables, and seeds.
As a trisaccharide, raffinose comprises three monosaccharides: glucose, fructose, and galactose. This complex sugar is less sweet than table sugar due to its intricate structure.
When raffinose undergoes hydrolysis, it breaks down into its constituent monosaccharide components.
Hydrolysis of raffinose is an enzymatic process usually occurring in the digestive system. Specific enzymes break the glycosidic bonds, releasing the individual sugars.

• Raffinose cannot be fully digested by humans because they lack the enzyme, b1-galactosidase, required for its breakdown in the upper digestive tract.
• It passes into the colon where bacterial fermentation occurs, often leading to gas production.
• Despite this, raffinose is valuable in the diet for its role as a prebiotic, promoting the growth of beneficial gut bacteria.

Understanding its structure and breakdown is crucial for comprehending human digestion and the impact of dietary sugars.

Glucose Fructose Galactose

Glucose, fructose, and galactose are the fundamental monosaccharides that make up the complex sugar, raffinose. Each of these sugars has distinct properties and plays vital roles in metabolism.

Glucose: Often called blood sugar, it is the primary energy source for the body. It is a simple sugar that circulates in the bloodstream and is utilized by cells for energy.

• Glucose is involved in cellular respiration, where it is broken down to release energy.
• Insulin, a hormone produced by the pancreas, helps regulate blood glucose levels.

Fructose: Known as fruit sugar, it is naturally found in many plants. Fructose is sweeter than glucose, making it a popular natural sweetener.

• Unlike glucose, fructose is primarily metabolized in the liver.
• High consumption of fructose has been linked to certain metabolic disorders.

Galactose: It is less common in its free form but is an important part of milk sugar, lactose.

• In the body, galactose is converted to glucose for energy.
• Galactose metabolism involves conversion to glucose-1-phosphate, which enters glycolytic pathways.

Understanding these monosaccharides helps in grasping how complex carbohydrates are broken down and used by the body for energy and other functions.