Within a double-stranded DNA molecule, adenine (A) forms hydrogen bonds with thymine (T), and cytosine (C) forms hydrogen bonds with guanine (G). What is the significance of the structural arrangement?

• A. It allows variable width of the DNA double helix.
• B. It permits complementary base pairing.
• C. It determines the tertiary structure of the DNA molecule.
• D. It determines the type of protein produced from the DNA.

Answer: (B)

Verified step by step guidance

1. Understand the concept of complementary base pairing in DNA: In a double-stranded DNA molecule, adenine (A) pairs with thymine (T) through two hydrogen bonds, and cytosine (C) pairs with guanine (G) through three hydrogen bonds.
2. Recognize the significance of complementary base pairing: This specific pairing ensures that the two strands of DNA are complementary to each other, meaning that the sequence of bases on one strand determines the sequence on the other strand.
3. Explore the structural implications: Complementary base pairing contributes to the uniform width of the DNA double helix, as the pairing between A-T and C-G maintains a consistent distance between the two strands.
4. Consider the biological importance: Complementary base pairing is crucial for DNA replication and transcription, as it allows the DNA to be copied accurately and transcribed into RNA, which is then translated into proteins.
5. Reflect on the broader impact: While complementary base pairing does not directly determine the tertiary structure of DNA or the type of protein produced, it is fundamental to the accurate transmission of genetic information, which ultimately influences protein synthesis.