Which of the following mRNA sequences could code for the polypeptide met-arg-ser-leu-glu?
5' ATGGAGGTTCGATGCGTA 3'
5' AUGAGUAGCUUCGAGUGG 3'
5' AUGCGUAGCUUGGAGUGA 3'
5' AUGCUAAAUGUGCGAUGA 3'

5'-AUGCGUAGCUUGGAGUGA-3'  

Explanation:

(a) Break the string into triplets.

5'-AUG-CGU-AGC-UUG-GAG-UGA-3'

The string contains six codons.

The initiation codon is AUG (Met)

That eliminates Options 1 and 4.

(b) Identify the stop codon

There are six codons, so the sixth is the stop codon, which must be UAA, UGA, or UAG .

That eliminates Option 2, which ends with UGG.

The correct answer must be Option 3.

(c) Check

Translate the codon string.

5'-AUG-CGU-AGC-UUG-GAG-UGA-3

    met   arg    ser    leu    glu    stop

That's the correct sequence.

they both go up but then go back down. they both end lower than they started. lastly, they both are competitive/the second on.

explanation: