Lesson Plan

• Describe how carbon dioxide is converted to bicarbonate in plasma.
• Explain the functions of carbonic anhydrase and the chloride shift in CO₂ transport.
• Compare the three forms of CO₂ transport in blood and their relative contributions.
• Interpret a diagram showing the movement of CO₂ from tissues to the lungs.
• Predict the impact of impaired plasma function on gas exchange efficiency.

• Projector and screen
• PowerPoint slides with CO₂ transport diagram
• Printed worksheet containing the summary table
• Whiteboard and markers
• Model of a red blood cell (optional)
• Quiz cards for quick formative checks

Begin with a quick “What carries gases in our blood?” poll to activate prior knowledge of oxygen transport. Highlight that carbon dioxide uses a different strategy, especially involving plasma. State that by the end of the lesson students will be able to describe the plasma‑based pathway and its key enzymes.

1. Do‑now (5'): Students list the three ways CO₂ is carried in blood on sticky notes.
2. Mini‑lecture (10'): Present the plasma pathway, emphasizing carbonic anhydrase and the chloride shift, using the slide diagram.
3. Guided practice (12'): Work through the chemical equations together, converting CO₂ → H₂CO₃ → H⁺ + HCO₃⁻.
4. Interactive activity (10'): In pairs, use the worksheet to fill the summary table and compare percentages of each transport form.
5. Formative check (8'): Quick quiz cards – students explain why plasma is essential for CO₂ transport.
6. Wrap‑up (5'): Teacher revisits the learning objectives and asks for one key takeaway from each student.

Summarise that plasma provides the medium for converting CO₂ to bicarbonate, the dominant transport form, and that the chloride shift maintains charge balance. Collect an exit ticket where each pupil writes one consequence of a malfunctioning plasma pathway. Assign a short homework: create a labelled flow diagram of CO₂ transport from tissue to lung.