RNA coding sequence for proteins

[Phil Core]

Simplistic Example
Given - DNA - RNA AATGTA codes for a protein.

1. Does the inverse ATGTAA usually/ever code for a protein?
2. Does the reciprocal RNA TTACAT usually/ever code for a protein?

 

[jim mcnamara]

RNA does not have "T", it has uracil, "U". ACTG are the nucleotides for DNA, "ACUG" for RNA
DNA overall has a "start end, 5 prime" and a "finish end, 3 prime". Groups of three nucleotides are called codons, like in your example.

There are start codons and stop codons. So the direction of the nucleotide sequence to interpret has a specific direction to it for a protein or polypeptide.

For example: DNA copying (replication)
DNA polymerase adds nucleotides to the deoxyribose (3') ended strand in a 5' to 3' direction. Lagging strand is synthesised in fragments. Nucleotides cannot be added to the phosphate (5') end because DNA polymerase can only add DNA nucleotides in a 5' to 3' direction. So a given set of codons has direction to it dictated overall by 5 prime- 3 prime, and stop and start codons.

So your question needs a tune up. There is direction, plus codons for stop and start.

A very misleading answer to the question as asked is yes. This ignores some combinations of nucleotide triplets could be a codon when "read forwards" and something else when "read backwards", may be a so-called dead end codon. Other names for these "garbage" triplets are termination codon or nonsense codon. I like "dead-end" for teaching.

 

[Phil Core]

Sorry I can not even get the basics correct. You are a good man Jim and I appreciate your answer. You made things a lot clearer for me.