Describe the importance of complementary base pairing between the 5′ to 3′ strand and the 3′ to 5′ strand (antiparallel strands)

Sourav PanOctober 29, 2024

Answered

Complementary base pairing between the 5′ to 3′ and 3′ to 5′ antiparallel strands is crucial for the structure and function of DNA. Here’s why it’s so important:

1. Maintains DNA Structure: Complementary base pairing allows for hydrogen bonding between specific nitrogenous bases (adenine pairs with thymine, and guanine pairs with cytosine) across the two antiparallel strands. This base pairing stabilizes the DNA double helix, maintaining its uniform width and allowing it to twist into a stable helical structure.
2. Ensures Accurate Replication: During DNA replication, complementary base pairing allows each strand to serve as a template for creating a new, identical strand. Because each base only pairs with its complementary partner, replication produces two identical DNA molecules, ensuring genetic information is accurately passed to daughter cells.
3. Enables DNA Repair and Proofreading: The specificity of complementary base pairing helps in DNA repair. Enzymes recognize mismatches and can correct errors by identifying the correct complementary base, which helps maintain genetic stability and prevents mutations.
4. Facilitates Transcription Accuracy: In transcription, complementary base pairing between DNA and RNA bases (where adenine pairs with uracil in RNA) ensures accurate transfer of genetic information from DNA to mRNA, which is essential for protein synthesis.

The antiparallel orientation, along with complementary base pairing, is key to DNA’s stability, replication fidelity, and proper functioning in the storage and transmission of genetic information.