Content Objective: Analyze the adaptations of fetal and adult hemoglobin for oxygen transport, including cooperative and allosteric binding, and explain the implications of the Bohr effect and oxygen dissociation curves. Additionally, evaluate cellular adaptations in erythrocytes, nephron cells, pneumocytes, and muscle fibers, assessing how these modifications optimize oxygen transport, gas exchange, and muscle function at the cellular and tissue levels.
Language Objective: Develop and articulate detailed explanations of hemoglobin adaptations for oxygen transport and the physiological mechanisms underlying the Bohr effect and oxygen dissociation curves. Construct and present clear descriptions of cellular adaptations in erythrocytes, nephron cells, pneumocytes, and muscle fibers, emphasizing how these structural changes enhance function in biological systems.
Syllabus Details:
B3.1.11 (HL)—Adaptations of foetal and adult haemoglobin for the transport of oxygen Include cooperative binding of oxygen to haem groups and allosteric binding of carbon dioxide.
B3.1.12 (HL)—Bohr shift - "Students should understand how an increase in carbon dioxide causes increased dissociation of oxygen and the benefits of this for actively respiring tissues."
B3.1.13 (HL) —Oxygen dissociation curves as a means of representing the affinity of haemoglobin for oxygen at different oxygen concentrations - "Explain the S-shaped form of the curve in terms of cooperative binding."
B2.3.7 (HL)—Adaptations to increase surface area-to-volume ratios of cells - "Include flattening of cells, microvilli and invagination. Use erythrocytes and proximal convoluted tubule cells in the nephron as examples."
B2.3.8 (HL)—Adaptations of type I and type II pneumocytes in alveoli - "Limit to extreme thinness to reduce distances for diffusion in type I pneumocytes and the presence of many secretory vesicles (lamellar bodies) in the cytoplasm that discharge surfactant to the alveolar lumen in type II pneumocytes. Alveolar epithelium is an example of a tissue where more than one cell type is present, because different adaptations are required for the overall function of the tissue."
B2.3.9 (HL)—Adaptations of cardiac muscle cells and striated muscle fibres - "Include the presence of contractile myofibrils in both muscle types and hypotheses for these differences: branching (branched or unbranched), and length and numbers of nuclei. Also, discuss whether a striated muscle fibre is a cell."
Activity 1 - Notes
Activity 3
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B. Expand Your Knowledge