Question

Suppose we find an organism on Titan whose hereditary molecule uses 3 base-pair molecules instead of the 4 found in DNA. Suppose also that it uses 75 amino acids instead of the 22 used by Earth-based life. What is the minimum length of the genetic “words” used by this hereditary molecule?

Answer 1

The minimum length of genetic words is 4.

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say, three base pair molecules are there instead of four... which means the number of nucleotiedes = 3.

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If the lenght of genetic code is 2 nucleotides = 3*3 = 9, the total amino acids are 75, but here only 9 is possible, hence this 2 length genetic code is wrong.

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If the lenght of genetic code is 3 nucleotides = 3*3*3 = 27, the total amino acids are 75, but here only 27 is possible, hence this 3 length genetic code is wrong.

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If the lenght of genetic code is 4 nucleotides = 3*3*3*3 = 81, the total amino acids are 75, here only 81 is possible, if each 4length genetic code codes for one aminoacid still 6 free genetic codes are available. Hence the answer i,e. the minimum length of gentic code "word"  used in the titan is FOUR.