The 3'-5' phosphodiester linkages inside a polynucleotide chain serve to join 


One nitrogenous base with pentose sugar


One DNA strand with the other DNA strand


One nucleoside with another nucleoside


One nucleotide with another nucleotide

Updated on : 2022-09-05
Verified by Toppr
Correct option is D)

  • A strand of DNA or RNA consists of nucleotides linked together by phosphodiester bonds. 
  • A phosphodiester bond exists between the phosphate of one nucleotide and the sugar 3' carbon of the next nucleotide. 
  • This forms a backbone of alternating sugar and phosphate molecules known as the sugar-phosphate backbone.
  • The two strands of DNA are also antiparallel (run in opposite directions) to one another. A strand of DNA can have direction 5'-3' or 3'- 5'.
  • One strand of the DNA molecule is 5'-3' and the other strand is 3'-5'. A DNA strand is assigned direction based on what is found at the end of the strands. 
  • The end of the strand with a free phosphate is the 5' end because phosphate attaches to the 5' carbon of the sugar. 
  • The end with a free OH group is the 3' end because the OH group is attached to the 3' carbon of the sugar.
So, the correct answer is option D.

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