Question

Refer the given reactions. (i) Adenine \(+X \rightarrow\) Adenosine (ii) Adenosine \(+\mathrm{Y} \rightarrow\) Adenylic acid What does \(X\) and \(Y\) represent here? \(X \quad\) Y (a) Phosphate group Sugar molecule (b) Sugar molecule Phosphate group (c) Sugar molecule Nitrogenous base (d) Nitrogenous base Sugar molecule

Short answer

X represents a Sugar molecule, and Y represents a Phosphate group.

Step-by-step solution

Identify the Components to Form Adenosine

Adenosine is composed of the nucleobase adenine attached to a sugar molecule. The sugar in RNA and DNA is ribose or deoxyribose, respectively. In this step, adenine is combined with a sugar molecule to form adenosine.

Determining X

Considering the information from Step 1, X must be the sugar molecule that combines with adenine to form adenosine.

Identify the Components to Form Adenylic Acid

Adenylic acid, also known as AMP (adenosine monophosphate), is formed by attaching a phosphate group to adenosine. This step involves the conversion of adenosine into adenylic acid by adding the phosphate group.

Determining Y

Based on the information from Step 3, Y is the phosphate group that is added to the adenosine molecule to form adenylic acid.

Key concepts

Nucleobase Adenine

When we delve into the world of genetics and molecular biology, we come across the crucial role played by nucleobases. Adenine is one of the five primary nucleobases found in DNA and RNA. In the context of adenylic acid formation, adenine provides one of the fundamental building blocks required for the synthesis of nucleic acids.

As a purine nucleobase, adenine pairs with thymine in DNA and with uracil in RNA through hydrogen bonds, forming the rungs of the double helix ladder. This connection is vital for the accurate replication and transcription of genetic code. Understanding how adenine interacts with other molecules to form complex structures like adenosine is key in appreciating the intricate dance of life at the molecular level.

Sugar Molecule in Nucleotides

The sugar molecule is another integral component of nucleotides, serving as the backbone to which nucleobases like adenine are attached. This sugar is either ribose in RNA or deoxyribose in DNA. The absence of one oxygen atom in deoxyribose, compared to ribose, is the reason for the 'deoxy' prefix in DNA.

During the formation of adenosine and subsequently adenylic acid, the sugar molecule plays a critical role. It acts as the scaffold that supports the structure of the nucleic acid, allowing for the attachment of the phosphate group. Moreover, the sugar's hydroxyl groups (-OH) enable the formation of phosphodiester bonds necessary for constructing the long, chain-like molecules of RNA and DNA.

Phosphate Group

A phosphate group consists of one phosphorus atom surrounded by four oxygen atoms. Within the context of nucleotides, this group is responsible for linking the sugar molecules together through phosphodiester bonds. These connections create the sugar-phosphate backbone of RNA and DNA strands.

The addition of the phosphate group to adenosine transforms it into adenylic acid, also known as AMP (adenosine monophosphate). This addition is energetically favorable and creates a molecule that is ready to be incorporated into nucleic acids, or used in cellular processes like energy transfer and signal transduction. The versatility of the phosphate group makes it an indispensable player in the symphony of cellular function.

RNA and DNA Components

The components of RNA and DNA are remarkably similar yet distinct enough to serve different biological functions. Each nucleotide in DNA and RNA is comprised of three essential parts: a nitrogenous base (like adenine), a sugar molecule (deoxyribose for DNA and ribose for RNA), and a phosphate group.

In DNA, the information is stored in a double-helix structure, which requires the nucleotides to pair in specific ways: adenine with thymine and guanine with cytosine. In RNA, however, adenine pairs with uracil, and the single-stranded nature allows it to fold into complex shapes, enabling it to perform various roles, including acting as a messenger between DNA and ribosomes, and facilitating protein synthesis. The formation of adenylic acid is but a snapshot of the dynamic processes giving rise to these extraordinary molecules that encode life itself.