Reading the notation

A small set of terms carries every part of this paper — the schedules reward you for naming the RIGHT mutation type or molecule, not just describing what happened.

📖 Terms used in gene expression

7 terms

Cover the right column and check you can say what each one means.

Substitution mutation: One base is swapped for another. The gene stays the same length — the least severe mutation type.
Silent / same-sense: A substitution that changes the codon but NOT the amino acid, thanks to the degeneracy of the genetic code — no effect on the protein.
Missense: A substitution that changes the codon AND the amino acid it codes for — may or may not change the protein's function.
Nonsense: A substitution that changes a codon into a STOP codon — the protein is cut short.
Temperature-sensitive enzyme: An enzyme whose SHAPE and activity depend on temperature — active within one temperature range and inactive outside it, without any mutation being involved.
Frameshift: An insertion or deletion of a base, which shifts every codon downstream — far more severe than a substitution, since it changes many amino acids at once.
Degeneracy (of the code): Most amino acids are coded for by more than one codon — the reason a base change does not always change the protein.

Before writing anything

Identify which of the three recurring strands this part is: protein synthesis/diagram completion, mutation severity, or gene-enzyme-environment metabolic pathway — each has its own checklist below.
Skim for a temperature-sensitive or environmental-cofactor scenario — these signal the deeper skill sections further down this page.

Practice for this standard covers the whole topic — flashcards and quiz.