IB Biology Topic D1.3: Mutations and Gene Editing Questionbank

P preserves the amino acid; P is neutral; both add genetic variation.

P preserves the amino acid; Q is neutral; both add genetic variation.

Q preserves the amino acid; Q is neutral; both add genetic variation.

P preserves the amino acid; Q is neutral; only Q adds genetic variation.

Three inserted bases create one codon, leaving every original domain codon unchanged.

Each insertion changes only one local codon, so every other domain codon retains its original grouping.

The later insertion reverses all amino-acid changes caused by the first insertion.

The later insertion restores downstream grouping, but the shifted interval can disable the domain.

Mutagens mainly cause random base substitutions rather than directing specific, adaptive changes.

DNA polymerase proofreading eliminates all replication errors, so mutations cannot be directed.

Mutagens increase mutation rate but not the exact site.

Mutagens preferentially target genes needed in the current environment to increase survival.

Somatic cells only; every offspring inherits the mutation

Somatic cells only; no offspring inherits the mutation

Some germ cells; some offspring can inherit the mutation

Some germ cells; every offspring inherits the mutation