Lesson Plan

• Describe how red blood cells transport O₂ and CO₂, referencing haemoglobin, carbonic anhydrase, haemoglobinic acid and carbaminohaemoglobin.
• Explain the Bohr effect and how the formation of Hb‑H⁺ and Hb‑CO₂ facilitates O₂ release in tissues.
• Interpret a schematic of the O₂/CO₂ transport pathway and identify the role of the chloride shift.
• Apply knowledge to predict how changes in pH or CO₂ levels affect haemoglobin affinity for O₂.

• Projector and screen
• PowerPoint/Google Slides with labelled transport diagram
• Printed worksheet with blank transport pathway table
• RBC model or 3‑D printed haemoglobin illustration
• Clickers or coloured cards for quick quizzes
• Whiteboard and markers

Begin with a short video clip of a person running and breathing heavily to hook interest. Ask students what they already know about how blood carries gases. State that by the end of the lesson they will be able to explain the detailed role of red blood cells and the key molecules involved.

1. Do‑now (5'): Quick multiple‑choice quiz on basic gas exchange concepts (displayed via clickers).
2. Mini‑lecture with diagram (10'): Explain RBC structure, haemoglobin binding, and carbonic anhydrase activity.
3. Guided activity (15'): Students label a blank transport pathway table (worksheet) in pairs, using the projected diagram.
4. Think‑Pair‑Share (10'): Discuss the Bohr effect and how Hb‑H⁺ and Hb‑CO₂ influence O₂ release; each pair records one real‑life example.
5. Formative check (5'): Exit‑ticket on the board – “One sentence describing how CO₂ is transported back to the lungs.”

Summarise the four key steps of O₂ and CO₂ transport, highlighting the roles of haemoglobin, carbonic anhydrase, haemoglobinic acid and carbaminohaemoglobin. Collect the exit‑ticket and remind students to complete the worksheet at home, extending the activity by comparing transport efficiency in sea‑level vs. high‑altitude conditions.