Boxi Learn › Biology › Stage 4 · Systems and Argument
From DNA letters to a protein
BIO-4 Inheritance is passed on in unitsBIO-2 Structure fits function
What many people think
Different cells in the body have different DNA.
The idea
Almost every cell in your body holds the same DNA; cells differ by which genes they read, three letters (a codon) per amino acid.
Explain it
A friend says a nerve cell has "nerve DNA" and a skin cell has "skin DNA". Use the idea of genes being switched on and off to explain why that is wrong, and name one exception.
Try at home
Write a sentence of three-letter words: THE CAT ATE THE RAT. Change one letter: how much of the meaning survives? Now delete one letter near the start and regroup into threes. Which mistake does more damage, and why?