Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Biology
Lesson Topic: Describe the structure of a DNA molecule: two strands coiled into a double helix with base pairs A‑T and C‑G.
Learning Objective/s:
  • Describe the double‑helix structure of DNA, including antiparallel strands and the sugar‑phosphate backbone.
  • Explain base‑pairing rules (A‑T, C‑G) and the number of hydrogen bonds involved.
  • Identify the three components of a nucleotide.
  • Interpret a DNA base‑pairing table to determine complementary bases.
  • Apply knowledge of DNA structure to explain how genetic information is stored.
Materials Needed:
  • Projector or interactive whiteboard
  • PowerPoint slides with DNA diagram
  • Printed worksheet with base‑pairing table
  • DNA model kit or 3‑D printed double‑helix model
  • Colored markers or sticky notes for building nucleotide models
  • Exit‑ticket cards
 Introduction:
Begin with a quick animation of a twisted ladder to capture interest. Ask students what they already know about genetic material and how it might be organized. Explain that today they will uncover the precise shape and components of DNA and how these enable it to store information. State that success will be shown by correctly labeling a DNA diagram and explaining base‑pairing rules.
Lesson Structure:
  1. Do‑now (5') – Students label a simple ladder diagram with “sugar‑phosphate” and “base” parts.
  2. Mini‑lecture (10') – Present the double‑helix model, antiparallel strands, and nucleotide components using slides.
  3. Guided practice (10') – In pairs, use colored sticks to build a short DNA segment, applying base‑pairing rules.
  4. Base‑pairing table activity (8') – Complete a worksheet matching bases and counting hydrogen bonds.
  5. Concept check (5') – Quick quiz via clickers or show of hands on key facts.
  6. Summary & exit ticket (7') – Students write one sentence describing why DNA’s structure is essential for genetic inheritance.
Conclusion:
Review the key features: antiparallel strands, sugar‑phosphate backbone, and A‑T / C‑G pairing. Prompt students to share one thing they found surprising. Collect exit tickets as a retrieval check and assign a short homework: draw and label a DNA double helix with all components.