0845 numbers, for example, are free to call for up to an hour, during the inclusive minutes of your call package if you're a BT customer. Yet call an 0844 number and you'll be charged up to 5.1p/minute, plus a connection fee of up to 15p.
The resulting mRNA is a single-stranded copy of the gene, which next must be translated into a protein molecule. During translation, which is the second major step in gene expression, the mRNA is read according to the genetic code, which relates the DNA sequence to the amino acid sequence in proteins (Figure 2).
The process of translation can be seen as the decoding of instructions for making proteins, involving mRNA in transcription as well as tRNA. The genes in DNA encode protein molecules, which are the workhorses of the cell, carrying out all the functions necessary for life.