IB Biology — Diagnostic Guide

Coverage Map

Diagnostic File	Topics Covered	Source Files
diag-cell-biology.md	Cell theory, prokaryotic vs eukaryotic, organelles, membrane transport, cell division	cell-biology.md
diag-molecular-biology.md	DNA replication, transcription, translation, PCR, enzyme function, gene expression	molecular-biology.md
diag-genetics.md	Monohybrid/dihybrid crosses, chi-squared, sex linkage, Hardy-Weinberg, pedigree analysis	genetics.md
diag-ecology.md	Energy flow, carbon/nitrogen cycles, population growth, biodiversity, conservation	ecology.md
diag-human-physiology.md	Action potentials, synapses, hormones, kidney function, immune system, gas exchange	human-physiology.md
diag-plant-biology.md	Photosynthesis, transpiration, mineral transport, plant hormones, reproduction	plant-biology.md

Grading Rubric

PASS Criteria

• Correctly solve at least 2 out of 3 Unit Tests with clear biological reasoning
• Correctly solve at least 2 out of 3 Integration Tests showing cross-topic understanding
• Use correct biological terminology and units throughout
• Demonstrate understanding of underlying mechanisms (not just memorised facts)

PARTIAL Criteria

• Correctly solve 1--2 Unit Tests and 1 Integration Test
• Shows conceptual understanding but with gaps in detail or terminology
• Partially correct explanations with some biological inaccuracies
• Correct calculations but incorrect or incomplete biological interpretation

FAIL Indicators

• Unable to solve any Unit Test completely
• Fundamental misconceptions (e.g., confusing transcription and translation, misunderstanding dominance)
• Cannot connect concepts across topics in Integration Tests
• Systematic errors in genetic crosses or Hardy-Weinberg calculations

Prerequisite Chains

Cell Biology
  └── Molecular Biology
        ├── Genetics
        │     ├── Ecology (population genetics)
        │     └── Human Physiology (immune system, inheritance)
        └── Plant Biology (gene expression in plants)

Ecology (independent foundation)
  └── Plant Biology (productivity, nutrient cycles)

Human Physiology (largely independent)
  └── Connections to Cell Biology (membrane transport, cell signalling)

Recommended order of diagnostic completion:

1. diag-cell-biology -- foundational cell concepts
2. diag-molecular-biology -- builds on cell biology
3. diag-genetics -- requires molecular biology understanding
4. diag-ecology -- largely independent, but benefits from genetics
5. diag-plant-biology -- requires molecular biology and ecology
6. diag-human-physiology -- largely independent, recommended last

Timing Recommendations

Diagnostic	Recommended Time	Notes
diag-cell-biology	35 minutes	Detailed comparison tables take time
diag-molecular-biology	40 minutes	Central dogma calculations are multi-step
diag-genetics	35 minutes	Chi-squared and Hardy-Weinberg require care
diag-ecology	35 minutes	Carbon cycle calculations have many steps
diag-human-physiology	45 minutes	Gas exchange calculations are complex
diag-plant-biology	35 minutes	Photosynthesis calculations are multi-step

Total recommended time: approximately 3.75 hours (spread across multiple sessions).

Full battery timing: Complete all 6 diagnostics over 2--3 sessions of 70--90 minutes each.

How to Use These Diagnostics

1. Complete each diagnostic without referring to notes or textbooks.
2. Check solutions immediately after each question to identify specific gaps.
3. If you score FAIL, review the corresponding source file thoroughly before retrying.
4. If you score PARTIAL, focus revision on the specific concepts from missed questions.
5. Integration Tests are the strongest predictor of exam performance -- they test your ability to apply knowledge across topics, which is what IB exams require.
6. Pay particular attention to the quantitative aspects (calculations, statistical tests) as these are frequently tested and easy marks when done correctly.