Question

The two functional groups present in a typical carbohydrate are: [2009] (a) \(-\mathrm{CHO}\) and \(-\mathrm{COOH}\) (b) \(>\mathrm{C}=\mathrm{O}\) and \(-\mathrm{OH}\) (c) \(-\mathrm{OH}\) and \(-\mathrm{CHO}\) (d) \(-\mathrm{OH}\) and \(-\mathrm{COOH}\)

Short answer

Option (c): c10OH and c010CHOe.

Step-by-step solution

Identify Carbohydrate Functional Groups

Carbohydrates are composed of carbon, hydrogen, and oxygen, and their backbones include several repeating units of the functional groups. To solve this, recognize that carbohydrates generally contain a carbonyl group (aldehyde or ketone) and hydroxyl groups.

Analyze Functional Groups in Options

Each option is a combination of functional groups: (a) Aldehyde group (c010CHOe010) and carboxyl group (c010COOHe010) (b) Carbonyl group (e010C=010O) and hydroxyl group (c10OH) (c) Hydroxyl group (c10OH) and aldehyde group (c010CHOe010) (d) Hydroxyl group (c10OH) and carboxyl group (c010COOHe010)

Match Functional Groups with Carbohydrate Characteristics

Carbohydrates typically contain a carbonyl group, which is either part of an aldehyde (c010CHOe010) or ketone (e010C=010O), and multiple hydroxyl (c10OH) groups. Check which option aligns with this composition.

Determine the Correct Option

Options (b) and (c) both contain valid functional groups for carbohydrates. However, option (c) ('- OH' and '- CHO') precisely identifies the functional groups found in typical sugars like glucose, which have an aldehyde (CHO) group at one end of the molecule.

Key concepts

Carbonyl Group

When exploring the world of carbohydrates, one term you'll frequently encounter is the carbonyl group. The carbonyl group is a functional group characterized by a carbon atom double-bonded to an oxygen atom, represented chemically as \( >\mathrm{C}=\mathrm{O} \). This group is quite versatile and forms the backbone of a wide array of organic molecules.

In carbohydrates, the carbonyl group manifests as either an aldehyde or a ketone. These forms are essential in classifying sugars as either aldoses or ketoses, depending on the position of the carbonyl group. In simple terms, if the carbonyl group is located at the end of the carbon chain, it's termed an aldehyde. If elsewhere, it's a ketone.

Understanding the carbonyl group's structure is crucial for recognizing the reactivity and properties of carbohydrates. This group is highly reactive due to the difference in electronegativity between the carbon and the oxygen, making it a key site for chemical interactions in metabolic processes.

Hydroxyl Group

The hydroxyl group is another fundamental player in the chemistry of carbohydrates. Represented as \(-\mathrm{OH}\), this group consists of an oxygen atom bound to a hydrogen atom. You'll find many hydroxyl groups attached to the carbon backbone in carbohydrates, making them polyhydroxy compounds.

This functional group's significance lies in its ability to form hydrogen bonds. Hydrogen bonding contributes to carbohydrates' solubility in water, making sugars like glucose easily dissolve and transportable in biological systems. It also affects the molecule's boiling and melting points, increasing their stability in different environments.

When you think about the hydroxyl group, imagine how it affects the sweetness of sugars and the viscosity of syrup. Its presence alters both physical and chemical properties to create the diverse roles carbohydrates play in nature and industry.

Aldehyde Group

In carbohydrates, particularly those classified as aldoses, you will encounter the aldehyde group. This group comprises a carbon atom bonded to a hydrogen atom and double-bonded to an oxygen atom, forming a unique structure \(-\mathrm{CHO}\).

The aldehyde group primarily distinguishes aldoses from ketoses, where the carbonyl is at the terminus of the carbon chain. This placement is pivotal in carbohydrate metabolism, impacting how sugars like glucose are broken down and utilized by cells.

The chemistry of aldehydes in sugars also influences their reducing properties. Aldoses can act as reducing sugars due to this exposed aldehyde group, making them crucial in biochemical processes such as fermentation, where specific pathways utilize these sugars' reactivity.

• The presence of the aldehyde group in a sugar affects its taste and its biological roles, serving crucial functions in energy production.
• In lab settings, identifying aldehyde groups helps distinguish between different types of sugars, providing insights into their specific functions and applications.