DNA Replication: Mechanisms and Enzymes · Zoology

The direction of DNA synthesis is always:

  1. 3' to 5' because that is the direction the template is read
  2. 5' to 3' because nucleotides add to the free 3'-OH group
  3. C-terminus to N-terminus along the polypeptide chain
  4. Random, depending on local dNTP availability
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Correct answer: 5' to 3' because nucleotides add to the free 3'-OH group

DNA synthesis always occurs in the 5' to 3' direction: the incoming nucleotide's 5'-phosphate attacks the 3'-OH of the last nucleotide in the growing chain, forming a phosphodiester bond.

Difficulty: Medium Question 16 of 20

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