DNA base codes....

A, T, G, C and U are the most commonly used one-letter-code by biologists to indicate bases or nucleotides. There are also other one-letter-codes which encode the four bases and their ambiguous positions in a DNA sequence such as M, R, W, S, Y, K, V, H, D, B and N. These codes mean either of two bases/nucleotides, any of three bases/ nucleotides, or any base/nucleotide at all.

Let me explain these codes with the etymology, and I am sure that I would be a mnemonic to memorize these codes.

 

What made Alexander Fleming to name Penicillin as Penicillin?

I have been frequently asked why I invented the name "Penicillin". I simply followed perfectly orthodox lines and coined a word which explained that the substance penicillin was derived from a plant of the genus Penicillium just as many years ago the word "Digitalin" was invented for a substance derived from the plant Digitalis.

Alexander Fleming on ‘Penicillin’, Nobel Lecture, December 11, 1945