Biology by Bradford
6.7.A, 6.7.BChanges to a chromosome
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6.7 Mutations: revision map
The subtopic in the middle and four tasks round it: label a diagram, complete two tables and fill 12 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
Mutations
AP Biology ยท Unit 6 Gene Expression and RegulationHover over a box to see it. Untick it to leave it off this sheet and its printout.
Name6.7.CGenes can move between prokaryotes
| Process | What happens |
|---|---|
| a cell takes up DNA from its surroundings | |
| a virus carries DNA from one cell to another | |
| one cell passes a plasmid to another through a pilus |
Bacteria do not reproduce sexually, but these processes let genes such as those for antibiotic resistance spread through a population, and between species.
Topic 6.7Mutations
6.7.AChanges to a gene
| Mutation | What changes | Effect on the protein |
|---|---|---|
| one base changed; same amino acid | none | |
| one base changed; different amino acid | may alter folding or function, as in sickle cell | |
| one base changed to a stop codon | a short, usually useless protein | |
| bases inserted or deleted, not in threes | every codon after it is changed |
6.7.A, 6.7.BWhere mutations come from and what they do
Mutations come from errors in DNA that escape proofreading, and from damage by mutagens such as UV light, X-rays and some chemicals. A mutation matters for inheritance only if it is in a cell that makes gametes (a germline mutation); a somatic mutation, in a body cell, is not passed on. Most mutations are neutral or harmful, but occasionally one gives an advantage in a new environment, and so mutation is the original source of all new alleles that selection acts on.
Word bank ConjugationdeletionduplicationFrameshiftinversionMissenseNonsensenormal chromosomereplicationSilentTransductionTransformation
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelChanges to a chromosome
- normal chromosome
- deletion
- duplication
- inversion
TableChanges to a gene
Mutation What changes Effect on the protein Silent one base changed; same amino acid none Missense one base changed; different amino acid may alter folding or function, as in sickle cell Nonsense one base changed to a stop codon a short, usually useless protein Frameshift bases inserted or deleted, not in threes every codon after it is changed GapsWhere mutations come from and what they do
Mutations come from errors in DNA replication that escape proofreading, and from damage by mutagens such as UV light, X-rays and some chemicals. A mutation matters for inheritance only if it is in a cell that makes gametes (a germline mutation); a somatic mutation, in a body cell, is not passed on. Most mutations are neutral or harmful, but occasionally one gives an advantage in a new environment, and so mutation is the original source of all new alleles that selection acts on.
TableGenes can move between prokaryotes
Process What happens Transformation a cell takes up DNA from its surroundings Transduction a virus carries DNA from one cell to another Conjugation one cell passes a plasmid to another through a pilus Bacteria do not reproduce sexually, but these processes let genes such as those for antibiotic resistance spread through a population, and between species.