| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: explain the terms gene, locus, allele, dominant, recessive, codominant, linkage, test cross, F1, F2, phenotype, genotype, homozygous and heterozygous |
Learning Objective/s:
- Describe the definitions of gene, locus, allele, dominant, recessive, codominant, linkage, test cross, F1, F2, phenotype, genotype, homozygous and heterozygous.
- Explain how these concepts are used to predict inheritance patterns in monohybrid crosses.
- Apply Punnett squares and test crosses to determine genotype and phenotype ratios, including calculation of recombination frequency for linked genes.
- Analyse real‑world examples such as ABO blood groups to illustrate codominance and linkage.
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Materials Needed:
- Projector or interactive whiteboard
- Slides with definitions and Punnett‑square diagrams
- Printed worksheets with cross problems
- Coloured markers or allele cards for modelling
- Calculator for recombination‑frequency calculations
- Exit‑ticket cards
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Introduction:
Begin with a quick poll: “What trait in your family shows a clear dominant or recessive pattern?” Connect this to prior knowledge of DNA and traits, then outline that by the end of the lesson students will confidently define key genetic terminology and use them to predict inheritance outcomes.
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Lesson Structure:
- Do‑now (5') – Students list examples of dominant, recessive, and codominant traits they know.
- Mini‑lecture (10') – Teacher presents concise definitions of all target terms with visual slides.
- Guided practice (12') – Whole‑class construction of a monohybrid Punnett square (AA × aa) and analysis of F₁/F₂ ratios.
- Test‑cross activity (10') – Small groups simulate a test cross using allele cards and record expected outcomes.
- Linkage & recombination (8') – Demonstration of linked genes; students calculate recombination frequency from a sample dataset.
- Quick‑check (5') – Exit ticket where each student writes one definition and one application example.
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Conclusion:
Summarise how precise terminology underpins accurate genetic predictions and revisit the key ratios derived today. Students complete an exit ticket to demonstrate mastery, and for homework they answer worksheet questions extending the Punnett‑square practice to dihybrid scenarios.
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