Edexcel iGCSE Biology-3.11 red blood cells- Study Notes- New Syllabus
Edexcel iGCSE Biology-3.11 red blood cells- Study Notes- New syllabus
Edexcel iGCSE Biology-3.11 red blood cells- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
3.11 understand how adaptations of red blood cells make them suitable for the transport of oxygen, including shape, the absence of a nucleus and the presence of haemoglobin
Red Blood Cells (RBCs) – Adaptations for Oxygen Transport
📝 Introduction
RBCs (erythrocytes) carry oxygen from the lungs to tissues.
Their structure is specialised to make this transport efficient.
🔑 Adaptations of RBCs
- Biconcave Shape
Thin in the middle, thicker at the edges → large surface area to volume ratio.
Oxygen diffuses in/out quickly.
Flexible → can squeeze through narrow capillaries. - No Nucleus
Mature RBCs lack a nucleus.
More space inside for haemoglobin, the oxygen-carrying protein. - Haemoglobin Presence
Haemoglobin binds oxygen to form oxyhaemoglobin.
Allows each RBC to carry a large amount of oxygen.
Releases oxygen in tissues where it’s needed.
📊 Summary Table
| Feature | Adaptation | How it Helps Oxygen Transport |
|---|---|---|
| Biconcave shape | Large SA:V | Faster diffusion of oxygen |
| No nucleus | More space | More haemoglobin → carries more O₂ |
| Haemoglobin | Oxygen-binding protein | Picks up O₂ in lungs, releases in tissues |
⚡ Quick Recap
RBCs = specialised oxygen carriers.
Biconcave → large surface area.
No nucleus → more room for haemoglobin.
Haemoglobin → binds oxygen efficiently.