What is the role of phosphodiester bonds within the sugar-phosphate backbone of DNA?

• A. They are responsible for the double helix structure of DNA.
• B. They connect the nitrogenous bases to the sugar molecules.
• C. They facilitate the replication of DNA by breaking and reforming.
• D. They link nucleotides together, forming the backbone of the DNA strand.

Answer: (D)

Verified step by step guidance

1. Understand the structure of DNA: DNA is composed of two strands forming a double helix. Each strand is made up of repeating units called nucleotides.
2. Identify the components of a nucleotide: Each nucleotide consists of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base.
3. Recognize the sugar-phosphate backbone: The backbone of DNA is formed by the sugar and phosphate groups of the nucleotides, linked together in a chain.
4. Learn about phosphodiester bonds: These bonds are covalent bonds that connect the phosphate group of one nucleotide to the sugar molecule of the next nucleotide, creating the continuous sugar-phosphate backbone.
5. Clarify the role of phosphodiester bonds: They are crucial for linking nucleotides together, forming the structural framework of the DNA strand, but do not directly involve the nitrogenous bases or the double helix structure.