13 exam-style questions · Biology only (B): not in Science (Double Award). Write your answer, check it against the mark scheme and tick the points you earned. Your marks stay on this device. Your writing is not saved.
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4.35B A DNA change and the phenotype
Exam question
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Explain how a change in a single base can change the phenotype.
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Total for this question: 3 marks
4.35B A DNA change and the phenotype
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A base substitution changes CUU to CUC. Both code for leucine. What is the effect?
(1)Total for this question: 1 mark
4.35B A DNA change and the phenotype
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Explain why an insertion of one base usually has a large effect.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Explain why a mutation that makes a stop codon has a large effect.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Suggest why sickle-cell anaemia is caused by a single base change.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Compare a substitution and a deletion mutation.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Illustrative simplified codon table.
| Codon | Amino acid |
|---|---|
| AAA | Lys |
| AAG | Lys |
| GAA | Glu |
| GUA | Val |
| UAA | stop |
Use the table. Explain why AAA → AAG has no effect on the protein.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
Exam question
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| Codon | Amino acid |
|---|---|
| AAA | Lys |
| AAG | Lys |
| GAA | Glu |
| GUA | Val |
| UAA | stop |
Use the table. Explain the effect of GAA changing to GUA.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
4.35B A DNA change and the phenotype
Exam question
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| Codon | Amino acid |
|---|---|
| AAA | Lys |
| AAG | Lys |
| GAA | Glu |
| GUA | Val |
| UAA | stop |
Use the table. Explain the effect of AAA changing to UAA.
(2)Write your answer, then press Show model answer and tick each mark point your answer makes. Your answer is not saved.
Total for this question: 2 marks
4.35B A DNA change and the phenotype
Exam question
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Identify the type of mutation where one base is replaced by another.
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Total for this question: 1 mark
4.35B A DNA change and the phenotype
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Explain why a mutation could change an enzyme's optimum temperature.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Explain why a mutation may change a protein's shape but still not change the phenotype.
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Total for this question: 2 marks
4.35B A DNA change and the phenotype
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Describe the link between DNA base sequence and protein structure.
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Total for this question: 2 marks
