Question

The 3' end of a polynucleotide contains _____ while the 5' end contains _____.

a) 5'-OH, 3'-phosphate
b) 5'-phosphate, 3'-OH
c) 5'-phosphate, 3'-phosphate
d) 5'-OH, 3'-OH

Answer 1

The 3' end of a polynucleotide chain has a free hydroxyl group (-OH), and the 5' end has a free phosphate group, making the correct answer b) 5'-phosphate, 3'-OH.

Step-by-step explanation:

The 3' end of a polynucleotide contains a free hydroxyl group (-OH) while the 5' end contains a free phosphate group. Therefore, the correct answer to the question is that the 3' end of a polynucleotide contains a 3'-OH group, and the 5' end contains a 5'-phosphate group, which is option b) 5'-phosphate, 3'-OH.

This polarity is important in determining the direction in which polynucleotides, such as DNA and RNA, are synthesized and read.