Question

This section contains multiple choice questions. Each question has 4 choices (a), (b), (c) and (d), out of which ONLY ONE is correct. . Which of the following have \(\alpha\) -glycosidic linkages? (i) starch (ii) cellobiose (iii) lactose (iv) maltose (v) cellulose (a) (i), (ii) and (iv) (b) (ii), (iii) and (v) (c) (i) and (iv) (d) (i), (iv) and (v)

Short answer

(a) Starch (b) Cellobiose (c) Lactose (d) Maltose (e) Cellulose (f) (i) Starch and (iv) Maltose Answer: (f) (i) Starch and (iv) Maltose

Step-by-step solution

Identify the glycosidic linkages in various carbohydrates

In this step, we will recall the structures of the carbohydrates listed and identify the type of glycosidic linkage present in each carbohydrate. (i) Starch: α-1,4 and α-1,6 linkages (ii) Cellobiose: β-1,4 linkage (iii) Lactose: β-1,4 linkage (iv) Maltose: α-1,4 linkage (v) Cellulose: β-1,4 linkage

Identify the carbohydrates with α-glycosidic linkages

In this step, we will find out which of the listed carbohydrates have α-glycosidic linkages. From our previous findings, we can see that starch (i) and maltose (iv) have α-glycosidic linkages.

Choose the correct answer

Based on our findings in step 2, the correct answer is (c) (i) and (iv), which includes starch and maltose as having α-glycosidic linkages.

Key concepts

Alpha-glycosidic linkage

Alpha-glycosidic linkages are a type of bond crucial in carbohydrate chemistry, particularly in how sugars connect. These linkages involve the joining of monosaccharides through oxygen in an alpha configuration. Imagine these bonds as little bridges between sugar molecules. In the case of alpha-glycosidic linkages, the OH group on the first carbon of the sugar points downward and forms a bond with another sugar molecule.

It's an essential structure in carbohydrates, like starch and maltose. Starch is composed of long chains of glucose with alpha-glycosidic linkages forming coils that are easily digestible by humans. Maltose, a sugar formed from two glucose units, also uses these alpha linkages, making it sweet and digestible.

Recognizing alpha-glycosidic linkages helps understand why some carbs can be easily broken down for energy, while others, like cellulose, resist digestion due to their beta-linkages.

Carbohydrate structure

Carbohydrates are organic molecules made from carbon, hydrogen, and oxygen, often in a ratio of 1:2:1. They can be simple sugars like glucose or complex structures like starches and cellulose.

Here's how they are structured:

• Monosaccharides: The simplest form, single sugar units like glucose and fructose.
• Disaccharides: Two monosaccharides joined, such as sucrose and lactose.
• Polysaccharides: Long chains of monosaccharides, such as starch, cellulose, and glycogen.

The structure of a carbohydrate determines its properties and digestibility. For example,

• Starch: Comprised of amylose and amylopectin, structured for easy breakdown into glucose.
• Cellulose: Forms a rigid structure due to beta-glycosidic linkages, providing plant fiber but not digestible by humans.

Understanding these structures helps explain why glucose is immediate fuel, while fibers promote digestive health.

Multiple choice questions in chemistry

Multiple choice questions (MCQs) in chemistry assess understanding of concepts efficiently. These questions often cover a wide range of topics and encourage quick thinking.

When solving MCQs concerning glycosidic linkages, it's crucial to:

• Carefully read each question and option.
• Understand key terminology like alpha- and beta-glycosidic linkages.
• Identify relevant structures for certain properties.

In the given question about

• Alpha-glycosidic linkages, options reflect the different bonds in carbohydrates.
• Practice makes perfect with MCQs, so try solving many to improve accuracy and speed.

These questions are not just about right or wrong; they're a way to understand chemistry concepts in depth.

Step by step solution in chemistry

Solving chemistry problems using a step-by-step approach aids comprehension and problem-solving skills. Here’s why it's beneficial:

• Systematic breakdown: Tackles problems without rushing, considering each part thoroughly.
• Structured learning: Easier to follow and learn problem-solving strategies.
• Error minimization: Identifies mistakes in individual steps before affecting the whole solution.

Take the example exercise on glycosidic linkages. Following a step-by-step solution helps a student:

• Recognize different types of linkages in carbohydrates.
• Apply knowledge to choose the correct answer in a multiple-choice format.

This method integrates learning with practical application, reinforcing understanding and retention of chemistry concepts.