In a prokaryotic cell, how would the mRNA be different from a tRNA? 1.The mRNA would have an SD box but the tRNA would not have an SD box. 2.The genes for both mRNA and tRNA would code for an ATG start codon. 3. The mRNA would be translated but the tRNA would not be translated. 4. Both mRNA and tRNA would have introns. A. 1,2 and 3 B. 1 and 3 C. 2 and 4 D. 4 only E. All of 1, 2, 3 and 4 are correct..