IB Biology SL D1.3 Mutation and Gene Editing Questions
Practise IB Biology SL D1.3 by classifying mutations, predicting molecular consequences and linking germ-line changes to inheritance.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Practise IB Biology SL D1.3 by classifying mutations, predicting molecular consequences and linking germ-line changes to inheritance.
Psammonobiotus balticus belongs to a group of protists (unicellular eukaryotic organisms) that have a shell surrounding most of the cell, which provides shelter from predators. The graph shows the frequency of varying shell lengths in a population of P. balticus.
Mutations may increase variation within a species. Compare and contrast substitution and insertion mutations.
Similarity:
a. both involve changes in the sequence of DNA/bases/nucleotides/triplets
OR
both may cause the production of a different amino acid/protein/polypeptide;
Difference:
b. substitution changes a base/nucleotide while insertion adds a base/nucleotide
OR
substitution changes one triplet while insertion changes more / causes frameshift
OR
substitution may not change protein/polypeptide function while insertion usually does;
Marking guidance:
Accept codon in place of triplet.
b. the contrast between substitution and insertion must be clear.
2
max
Thrombophilia is a human genetic condition where the blood has an increased tendency to clot. The condition is caused by a single base substitution mutation in DNA. If a person is homozygous for the gene, they are at greater risk for developing a blood clot than an individual who is heterozygous. The pedigree chart shows the inheritance of thrombophilia in a family.
Explain how a single base substitution mutation in DNA can cause a change to a protein.
| a | sequence of DNA bases determines the amino acid sequence of a protein; |
| b | changing one base (on the DNA) can cause the triplet/mRNA to code for a different amino acid; |
| c | changing one base (on the DNA) causes a different protein to be made (during translation); |
The Cancer Council of New South Wales has stated that one in five cancer deaths are caused by smoking. How can smoking cause cancer?
20 % of smokers get cancer.
Cigarette smoke contains mutagenic chemicals.
Smoking reduces the rate of mitosis in cells.
Smoking is addictive.
B