Mass Transport Flashcards
1
Q
Erythrocytes (Red Blood Cells)
A
- Biconcave to increase surface area for diffusion of O₂
- Flat and thin (1 cell thick) to allow for a short diffusion pathway
- Large amount of haemoglobin to increase the rate of diffusion
- No nucleus or organelles to maximise space for haemoglobin so more O₂ can be transported
2
Q
Haemoglobin
A
- Large globular proteins with a quaternary structure (made of 4 polypeptide chains)
- Each chain has a haem group containing an iron ion (Fe⁴⁺) which gives haemoglobin its red colour
- Each Hb molecule can bind with up to 4 O₂ molecules (O₂ binds to haem group)
3
Q
Formation of Oxyhaemoglobin
A
- In the lungs, O₂ diffuses from the alveoli to the capillaries and into the RBCs where it associates with haemoglobin and forms oxyhaemoglobin
- Hb + 4O₂ ⇄ HbO₈
- Haemoglobin + Oxygen ⇄ Oxyhaemoglobin
4
Q
High Affinity Haemoglobin
A
- Easily takes ups O₂
- Releases O₂ less easily
5
Q
Low Affinity Haemoglobin
A
- Takes up O₂ less easily
- Releases O₂ easily
6
Q
Factors impacting O₂’s affinity for O₂
A
- Partial Pressure of O₂
- Partial Pressure of CO₂
- Haemoglobin saturation
7
Q
Where in the body are high affinity haemoglobin found?
A
- In the lungs
- Higher pO₂ which promotes O₂ loading
8
Q
Where in the body are low affinity oxygen found?
A
- In O₂ starved areas, e.g. the lungs
- Lower pO₂ which promotes O₂ unloading
9
Q
Co-Operative Binding
A
- As each O₂ molecule binds to the haemoglobin, it changes the shape of the haemoglobin in a way that makes it easier for further O₂ molecules to bind
- This is the case for the first 3 molecules of O₂
- After the 3rd molecule, its harder for the 4th molecule to bind
10
Q
A
