Point 11 of 25 — Lesson 1: Types of RNA, Genetic Code and Protein TranslationQuestion bank: 14 questions (14 with pictures)
11Why a triplet code?
The sequence of nucleotides in DNA is transcribed into a complementary triplet sequence in mRNA, which goes to the ribosome and is translatedinto a sequence of amino acids.
How many nucleotides stand for one amino acid?
20 different amino acids must be specified using an alphabet of only 4 letters(A, G, C, U/T).
One-letter "words": only 4 combinations – too few.
Two-letter words: 4² =16 – still fewer than 20.
Three-letter words: 4³ =64 – more than enough.
So the smallest possible code word is three nucleotides, called acodon.
By 1960 there was good evidence for a triplet code; by 1965 the meaning of all codons was worked out.
📝 Question bank for this point
14 questions linked to this point only, 14 of them with pictures.
