Mindmap 7.1 HAEMOGLOBIN
- Created by: LaurenSkyeShelley
- Created on: 13-06-17 17:52
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- Chapter 7: Mass Transport: Haemoglobin
- Protein molecules with a quaternary structure
- The structure has evolved to make it efficient at loading oxygen under one set of conditions but unloading it under a different set of conditions
- 1. Primary Structure: Sequence of amino acids in the 4 polypeptide chains
- 2. Secondary structure: n which each of these polypeptide chains is coiled into a helix
- 3. Tertiary Structure: in which each chain is folded into a precise shape - an important factor in its ability to carry oxygen
- 4. Quarternary Structure: in which all 4 polypeptides are linked together to form an almost spherical molecule
- Each polypeptide is associated with a haem group
- A haem group contains (Fe2+) ion and one of these ions can combine with 4 O2 molecules that can be carried by a single haemoglobin molecule in humans
- Each polypeptide is associated with a haem group
- The structure has evolved to make it efficient at loading oxygen under one set of conditions but unloading it under a different set of conditions
- Loading and unloading oxygen
- Loading: The process by which haemoglobin binds to oxygen. It is also known as associating. In humans it takes place in the lungs
- Unloading: The process by which haemoglobin releases oxygen it is also known as disassociating. In humans it takes place in tissues.
- Affinity
- Haemoglobin with high affinity for oxygen take up oxygen more readily but release it less easily
- Haemoglobin with low affinity for oxygen take up oxygen less easily but release it more readily.
- The role of haemoglobin
- To transport oxygen
- To do this efficiently, haemoglobin must:
- Readily associate with oxygen at the surface where gas exchange takes place
- It is able to do both these as haemoglobin can change its affinity under different conditions
- Readily dissociate oxygen at tissues requiring it.
- It achieves this because its shape changes in the presence of certain substances such as CO2
- In the presence of CO2 its affinity is lower
- It is able to do both these as haemoglobin can change its affinity under different conditions
- Readily dissociate oxygen at tissues requiring it.
- Readily associate with oxygen at the surface where gas exchange takes place
- To do this efficiently, haemoglobin must:
- To transport oxygen
- Why are there different types of haemoglobins
- Eac species produces a haemoglobin with a slightly different amino acid sequence
- So they have a slightly different tertiary and quaternary structure
- So have different oxygen binding properties
- So they have a slightly different tertiary and quaternary structure
- Eac species produces a haemoglobin with a slightly different amino acid sequence
- Protein molecules with a quaternary structure
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