What direction do transcription, translation and DNA replication occur?

[Stick]

Different sources are providing conflicting evidence.

[psyxwar]

Different sources are providing conflicting evidence.

Transcription occurs 5'-3', with the template being read 3'-5'. DNA replication is the same, hence why you have a leading and lagging strand. I'd think the mRNA is read 5'-3' in translation, as you start with the start codon (which is on the 5' side) and translate from there.

[Yacoubb]

Different sources are providing conflicting evidence.

* In transcription, the template strand is transcribed 3' to 5', but the pre-mRNA molecule is built in a 5' to 3' direction.

* DNA replication: DNA polymerase builts complementary strands 5' to 3' in an anti-parallel direction.

* In PCR, following the hybridisation of the primer to the 3' ends of the target DNA strands, the primer is extended by taq polymerase and the complementary DNA strand is built 3' to 5' as the primer is being extended.

[Scooby]

* In transcription, the template strand is transcribed 3' to 5', but the pre-mRNA molecule is built in a 5' to 3' direction.

* DNA replication: DNA polymerase builts complementary strands 5' to 3' in an anti-parallel direction.

* In PCR, following the hybridisation of the primer to the 3' ends of the target DNA strands, the primer is extended by taq polymerase and the complementary DNA strand is built 3' to 5' as the primer is being extended.

read

always 5' to 3' for polynucleotide synthesis

[Yacoubb]

read

always 5' to 3' for polynucleotide synthesis

Woops - okay thanks for that!

[Yacoubb]

read

always 5' to 3' for polynucleotide synthesis

So the primer anneals to the 3' end, but the primer is extended 5'to 3'?

[Scooby]

So the primer anneals to the 3' end, but the primer is extended 5'to 3'?

yup. Taq polymerase attaches to the 3' end of the primer and synthesises the daughter strand in a 5' to 3' direction

[Yacoubb]

yup. Taq polymerase attaches to the 3' end of the primer and synthesises the daughter strand in a 5' to 3' direction

Thanks for that!

[Stick]

read

always 5' to 3' for polynucleotide synthesis

OK thanks for clearing that up. Should be easy to remember now.