Structure and Functions of Nucleic Acids (DNA and RNA)

Introduction

Nucleic acids—DNA and RNA—are fundamental biomolecules essential for the storage and transmission of genetic information. They play a crucial role in gene expression and regulation, ensuring the proper functioning of cellular activities.

Structure of DNA and RNA

DNA Structure

DNA (Deoxyribonucleic Acid) is a double-stranded helical molecule composed of nucleotides. Each nucleotide consists of a deoxyribose sugar, a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, and guanine).

• Double-stranded helix stabilized by hydrogen bonds
• Base pairing follows Chargaff’s rules: A-T and G-C
• Stores genetic information in the nucleus

RNA Structure

RNA (Ribonucleic Acid) is a single-stranded molecule involved in protein synthesis. It contains ribose sugar and replaces thymine with uracil.

• Single-stranded, flexible structure
• Types: Messenger RNA (mRNA), Transfer RNA (tRNA), Ribosomal RNA (rRNA)
• Functions in transcription and translation

Biological Roles of DNA and RNA

DNA: Genetic Information Storage

DNA encodes genetic instructions essential for the development, growth, and function of all living organisms.

• Replication ensures genetic continuity
• Transcription enables gene expression
• Mutation and repair mechanisms maintain genomic integrity

RNA: Genetic Information Expression

RNA translates genetic information into proteins, facilitating cellular function.

• mRNA carries instructions from DNA to ribosomes
• tRNA assists in amino acid assembly
• rRNA contributes to ribosome function

Conclusion

DNA and RNA are indispensable in genetic storage and expression, ensuring life’s continuity through replication and protein synthesis.