Problem 8 - A Guide to the Principles of Animal Nutrition

Question

Fill in the monosaccharides that compose each disaccharide listed below and the enzyme required to break the bond between them. $$ \begin{array}{|l|l|l|l|} \hline \text { Sugar } & \text { Enzyme } & \text { Monosaccharide } 1 & \text { Monosaccharide } 2 \\ \hline \text { Sucrose } & & & \\ \hline \text { Maltose } & & & \\ \hline \end{array} $$

Step-by-Step Solution

Answer

Sucrose is glucose + fructose, enzyme is sucrase; maltose is glucose + glucose, enzyme is maltase.

Step 1: Understanding Disaccharides

A disaccharide is a sugar formed when two monosaccharides are joined by a glycosidic bond. Examples include sucrose and maltose. Each has a specific enzyme that catalyzes its hydrolysis.

Step 2: Identify Monosaccharides in Sucrose

Sucrose is composed of two monosaccharides: glucose and fructose. The glycosidic bond between them is cleaved by the enzyme sucrase.

Step 3: Identify Monosaccharides in Maltose

Maltose is composed of two glucose molecules. The enzyme maltase breaks the glycosidic bond between these two glucose units.

Step 4: Complete the Table for Sucrose

For sucrose: Enzyme = Sucrase, Monosaccharide 1 = Glucose, Monosaccharide 2 = Fructose. Fill these details in the table for sucrose row.

Step 5: Complete the Table for Maltose

For maltose: Enzyme = Maltase, Monosaccharide 1 = Glucose, Monosaccharide 2 = Glucose. Fill these details in the table for maltose row.

Key Concepts

Monosaccharides

Monosaccharides are simple sugars, which are the basic building blocks of carbohydrates. These single-molecule sugars cannot be broken down into simpler sugars, making them fundamental components in nutrition. Two of the most common monosaccharides are glucose, which provides immediate energy for cellular activity, and fructose, found in many fruits and honey, contributing to the sweet flavor.
While monosaccharides can often be found freely in nature, they frequently bond together forming disaccharides. Disaccharides, like sucrose and maltose, consist of two monosaccharide units joined by glycosidic bonds. Understanding these basics helps in identifying the composition of various sugars, which is crucial for analyzing how they are digested and metabolized by our bodies.

Enzymes in digestion

Enzymes play a critical role in digestion by catalyzing biochemical reactions, breaking down complex molecules into simpler ones that can be absorbed by the body. In the context of disaccharides, specific enzymes are responsible for hydrolyzing the bonds between monosaccharides, facilitating their absorption.
For instance, sucrase is the enzyme that catalyzes the breakdown of sucrose into glucose and fructose. On the other hand, maltase is the enzyme which helps cleave maltose into two glucose molecules. These enzymes ensure that sugars are efficiently processed into forms our bodies can use for energy and other functions. Without these enzymes, disaccharides would not be able to contribute to our nutritional needs as they wouldn't be broken into absorbable forms.

Glycosidic bonds

A glycosidic bond is a covalent bond that joins a carbohydrate molecule to another group, which can be another carbohydrate. This bond is crucial in linking monosaccharides together to form disaccharides and more complex carbohydrates.
The formation of glycosidic bonds involves a dehydration reaction where a water molecule is removed. Conversely, during digestion, these bonds are broken through a process known as hydrolysis, which involves adding a water molecule.

• In sucrose, a glycosidic bond connects glucose and fructose, forming a sweet-tasting sugar commonly found in many plants.
• In maltose, two glucose molecules are linked, and this bond is vital for producing malt in various food products.

Understanding these bonds helps explain how digestion enzymes work to efficiently convert food into energy, underpinning the essential processes that sustain life.