Biology Proteins and amino acid sequence?

Question

A protein has the following amino acid sequence. Construct a mRNA nucleotide sequence of the structural gene.

Answer 1

You would need the amino acid sequence first.  Then, look at the amino acid sequence and use a codon table to determine what nucleotides code for that amino acid.

Answer 2

AUAGCCAGUUGGAGCAGGCUUUAAA

...how's that?

Answer 3

You will need to use a codon table. Wikipedia has one: http://en.wikipedia.org/wiki/Codon

The first letter in the protein is A which is for alanine. GCX codes for alanine (where X could be any nucleotide). So your first three codons could be GCA. Just do this for every amino acid, but....

Are you sure this is the amino acid sequence?? Because those letters are also those used for nucleotides, and there are only four nucleotides and twenty amino acids...it would just be a very odd coincidence. I think the question is probably giving you the nucleotide sequence of the mRNA coding for the protein, and it wants you to figure out the protein.

Assuming that this is a mRNA transcipt I'm guessing this is:

3' - AUA GCC AGU UGG AGC AGG CUU UAA A - 5'

Once again, use a codon table to figure out which codons go with which amino acids. AUA codes for Isoleucine, GCC codes for alanine, etc. So the first few amino acids of your protein would be (remembering that the protein would be coded from 3' -> 5'):

Ala - Ile - Ser - .....etc.

Or maybe the question is giving you the mRNA of the protein and asking you to figure out the DNA that codes for it. To do this you need to know that:

A (adenine) binds to T (thymine) [[NOT U!! Because remember DNA has T and RNA has U)

G (guanine) binds to C (cytosine)

Then your DNA would be:

5' - TAT CGG TCA ACC TCG TCC CAA ATT T - 3'