I have often referred to DNA as the cell’s “hard drive” – it is an information storage medium, but does not itself process the information. Recently a student in an introductory course asked how that information is used, so I extended the digital analogy this way:
On your hard drive, information is stored magnetically. The direction of the magnetic field designates a binary coding system of 1’s and 0’s. So let’s say the following sequence is stored on your hard drive:
01010100010010000100100101010011001000000100100101010011001000000100 000100100000010100000101001001001111010101000100 01010100100101001110
This information can be copied to a flash drive, where it is still stored as 01010100010010000100100101010011001000000100100101010011001000000100 000100100000010100000101001001001111010101000100 01010100100101001110, but there is a subtle difference. In the flash drive, it is not stored magnetically. It is stored electronically. So the same information is copied (transcribed) to a slightly different medium, just as the information on DNA is transcribed to mRNA.
Now we can take that same information on the flash drive, and send it to the printer. The printer will receive the string of 1’s and 0’s, interpret them, and then spit out a piece of paper that says:
THIS IS A PROTEIN
The printer translates the binary code (1’s and 0’s) to ASCII code in the form of letters, the same way a ribosome translates the mRNA code into amino acids and polypeptides.