Question

Indicate whether each statement is true or false: (a) Maltose is a monosaccharide. (b) Polysaccharides are a type of carbohydrate. (c) All carbohydrates have an oxygen to hydrogen ratio of 1: 2 .

Short answer

Statement A: False. Maltose is a disaccharide, not a monosaccharide. Statement B: True. Polysaccharides are a type of carbohydrate. Statement C: False. Although most carbohydrates have an oxygen to hydrogen ratio of 1:2, there are exceptions.

Step-by-step solution

Statement A: Maltose is a monosaccharide.

Maltose is a disaccharide, not a monosaccharide. Monosaccharides are the simplest form of carbohydrates and cannot be broken down into simpler sugars. Examples of monosaccharides are glucose, fructose, and galactose. Maltose, on the other hand, is formed by the combination of two glucose molecules. So, the statement is false.

Statement B: Polysaccharides are a type of carbohydrate.

Polysaccharides are indeed a type of carbohydrate. They are long chains of monosaccharide units bonded together. Examples of polysaccharides include starch, glycogen, and cellulose. So, the statement is true.

Statement C: All carbohydrates have an oxygen to hydrogen ratio of 1:2.

Carbohydrates are composed of carbon, hydrogen, and oxygen atoms. The general formula for carbohydrates is Cn(H2O)n, where n is the number of carbon atoms. In this formula, the oxygen to hydrogen ratio is 1:2, which is a characteristic feature of carbohydrates. However, there are exceptions, such as deoxyribose, which do not follow this ratio. Since the statement specifies "all carbohydrates," the statement is false.

Key concepts

Monosaccharides

Monosaccharides are the simplest form of carbohydrates. They act as the fundamental building blocks for more complex carbohydrates. A key characteristic of monosaccharides is that they contain just one sugar unit. This means they cannot be further broken down into simpler sugars by hydrolysis.

Common examples of monosaccharides include:

• Glucose - often referred to as 'blood sugar,' is a primary energy source for cells.
• Fructose - found naturally in fruits and is the sweetest of the sugars.
• Galactose - a component of lactose, the sugar found in milk.

Monosaccharides play crucial roles in metabolism. By providing a quick source of energy, they are vital for cellular processes. In this simplicity lies their power, enabling them to be easily absorbed and utilized by the human body.

Polysaccharides

Polysaccharides are complex carbohydrates formed by the linkage of multiple monosaccharide units. They serve various functions ranging from energy storage to providing structural support in organisms. Polysaccharides are generally found in long chains, which can be either unbranched or branched.

Some important polysaccharides include:

• Starch - a primary storage form of energy in plants.
• Glycogen - serves as the main storage form of energy in animals, particularly in the liver and muscles.
• Cellulose - a major component of the cell wall in plants, providing structural support.

These polysaccharides play diverse roles, such as storing energy or offering rigidity and strength to plant cells. The diversity in their structure gives them unique properties, making them essential for life.

Disaccharides

Disaccharides are carbohydrates made up of two monosaccharide units bound together. They play important roles in nutrition, serving as an energy source and as part of digestion. Unlike monosaccharides, disaccharides need to be broken down into their monosaccharide components during digestion for absorption.

Common disaccharides include:

• Maltose - composed of two glucose molecules, often found in germinating seeds and used in brewing.
• Sucrose - made up of glucose and fructose, and commonly known as table sugar.
• Lactose - consists of glucose and galactose, found in milk and dairy products.

Disaccharides are sweet to taste and are a common feature in the human diet. They must be hydrolyzed to monosaccharides before the body can make use of them as energy sources.