Which one of the following statements is not correct?
Together with proteins, rRNA provides a site for polypeptide synthesis.
All DNA molecules are unbranched polymers of nucleotides
DNA is synthesised in a 5'-3' direction while RNA synthesis occurs in a 3'-5' direction.
A tRNA anticodon may pair with more than one codon.
Both DNA and RNA synthesis occur in the 5'-3' direction. The synthesis of DNA and RNA involves the addition of nucleotides to the growing chain in a specific direction.
In DNA replication, the DNA polymerase enzyme adds nucleotides to the 3' end of the growing DNA strand, extending it in the 5'-3' direction. This means that DNA is synthesised in a 5'-3' direction on both the leading and lagging strands during DNA replication.
Similarly, during transcription, which is the process of synthesising RNA from a DNA template, RNA polymerase adds nucleotides to the 3' end of the growing RNA strand, also in the 5'-3' direction. The RNA molecule is synthesised in the 5'-3' direction, complementary to the template DNA strand.
So, in both DNA and RNA synthesis, the addition of nucleotides occurs in the 5'-3' direction.
Hence, the correct answer is option 3.