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4 Cards in this Set
- Front
- Back
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Describe the structure of haemoglobin? |
*Primary structure - 4 polypeptide chains. *Secondary structure - Coiled into helix. *Tertiary structure - Each polypeptide is folded into precise shape {to carry O2}. *Quarternary structure - Polypeptide chains linked to form almost spherical molecule. *Polypeptides each have Haem group & is a globular protein. Structure curled up so hydrophilic side chains face outwards & hydrophobic chains face inwards - Soluble - Good for transport in blood. |
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What types of haemoglobin are there? |
*Haemoglobin with a high affinity for oxygen. These take up oxygen more easily but release less readily.
*Haemoglobin with a low affinity for oxygen. These take up oxygen less easily but release it more readily. |
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What is the role of haemoglobin & how much oxygen can a haem group hold? |
*To transport oxygen, to do this it must:- -> Readily associate with oxygen at the gas exchange surface. -> Readily dissociate from oxygen at the tissue requiring it.
*1 oxygen molecule per haem group:- Hb + 4O2 <-> Hb(O2)4 |
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When does haemoglobin have a high affinity & a low affinity for oxygen? |
*High affinity for oxygen at gas exchange surface so oxygen binds.
*Low affinity for oxygen at respiring tissues. High concentration of CO2 causes Hb to change shape, releasing oxygen. |
