The number of phosphodiester bonds in a double stranded fragment of DNA with fournucleotides in each strand is
Correct answer: C. 6
- A. 3
- B. 4
- C. 6
- D. 8
Explanation
In a DNA strand, each nucleotide is connected to the next by a phosphodiester bond. For a strand of four nucleotides, there are three bonds. Since the DNA is double stranded, there are two such strands, each with three bonds, making a total of six phosphodiester bonds. Option C correctly accounts for both strands, while Options A, B, and D are incorrect as they miscalculate the number of bonds per strand or fail to account for both strands.
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About Structure of DNA
DNA structure includes nucleotides made of deoxyribose, phosphate and nitrogenous bases, arranged in two antiparallel polynucleotide strands. Questions cover the double helix, phosphodiester and hydrogen bonds, complementary base pairing between adenine and thymine and between guanine and cytosine, and the significance of major and minor grooves.
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