This deep dive covers Gas Transport in Blood within Gas Exchange in Humans for GCSE Biology. Lung structure, alveoli adaptations, breathing mechanism, gas transport in blood, and effects of smoking It is section 7 of 19 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 19
Practice
19 questions
Recall
23 flashcards
Gas Transport in Blood
Oxygen Transport
- Majority bound to haemoglobin in red blood cells as oxyhaemoglobin (HbO₂)
- Small amount dissolved directly in blood plasma
- Each haemoglobin molecule can carry 4 oxygen molecules
- Oxygen binding is reversible: picks up O₂ in lungs, releases in tissues
- Oxygen saturation: percentage of haemoglobin carrying oxygen (normally 97-99%)
Carbon Dioxide Transport
- Most CO₂ is transported dissolved in plasma or as hydrogen carbonate ions
- A smaller amount is bound to haemoglobin
- CO₂ reacts with water inside red blood cells to form carbonic acid, which dissociates to release hydrogen carbonate ions into plasma
- Process is reversed in the lungs to release CO₂ for exhalation