IB Biology HL A4.1.2 Sequence evidence Question Bank
Practise IB Biology HL A4.1.2 by comparing molecular sequences to infer phylogeny, estimate divergence and evaluate biological evidence.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Compare protein sequences to infer phylogeny and estimate divergence with an evolutionary clock.
- Evaluate sequence alignments against thresholds when judging protein safety or biological relationships.
A4.1.2—Evidence from sequences question 1
[Maximum number: 4]
Proteins play essential roles in all forms of life.
Describe how a protein that is common to many organisms can be used in evolutionary studies.
a. amino acid sequence of the protein from each organism is compared;
b. changes in (base/amino acid) sequence accumulate over time;
c. due to mutation;
d. positive correlation between number of (base/amino acid) differences between (two) species and time they diverged from a common ancestor
OR
fewer the (base/amino acid) differences, the less time since diverged from a common ancestor / more closely related;
e. cladograms illustrate probable sequence of divergence/evolutionary origins;
f. accumulation of mutations can be used as a molecular clock/allows time since evolutionary divergence to be estimated;
4 max
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