Haemoglobin Flashcards
What are haemoglobins?
Haemoglobin are a group of chemically similar protein molecules found in a wide variety of organisms, specialised for oxygen transport
What is the function of haemoglobin?
Haemoglobin is adapted to efficiently load oxygen under one set of conditions and unload it under another set of conditions
What is the primary structure of haemoglobin?
The sequence of amino acids in the four polypeptide chains
Describe the secondary structure of haemoglobin
Each polypeptide chain is coiled into a helix
How does the tertiary structure of haemoglobin contribute to its function?
Each polypeptide chain is folded into a precise shape, which is essential for its ability to carry oxygen
Describe the quaternary structure of haemoglobin
Four polypeptides are linked together to form an almost spherical molecule
What is the role of the haem group in haemoglobin?
Each polypeptide is associated with a haem group that contains a ferrous ion (Fe2+), which can bind to oxygen
How can oxygen molecules can one haemoglobin molecule carry?
One haemoglobin molecule can carry up to four oxygen molecules, (O2) as each Fe2+ ion binds one O2 molecule
What is the process of haemoglobin binding with oxygen called?
Where does the process of oxygen loading take place in humans?
Loading or associating, which takes place in the lungs
What is the process of haemoglobin releasing oxygen called?
Unloading or disassociating, which takes place in the tissues
What is meant by “low affinity for oxygen” in a haemoglobin?
A low affinity for oxygen means haemoglobin takes up oxygen less easily but releases oxygen more easily
What is meant by “high affinity for oxygen” in a haemoglobin?
A high affinity for oxygen within haemoglobin means haemoglobin takes up oxygen easily but releases it less easily
What is the primary function of haemoglobin in organisms?
To carry oxygen from the gas - exchange surface to the tissues for respiration
What did scientists discover about haemoglobin in different organisms?
Different organisms have different types of haemoglobin with varying oxygen uptake and release properties
Why do different haemoglobins have different affinities for oxygen?
Due to their differences in their amino acid sequences, leading to variations in their tertiary and quaternary structures
How does the structure of haemoglobin affect its oxygen - binding properties?
The shape of the molecule determines whether it has a high or low affinity for oxygen
How does a low - affinity haemoglobin behave?
It binds to oxygen less easily but releases it more readily
How does a high - affinity haemoglobin behave?
It readily binds to oxygen but releases it less easily
Describe the conditions you would expect (specifics below) when oxygen is being loaded (associated) by haemoglobin
CONDITIONS:
1/ Region of body
2/ Oxygen concentration
3/ Carbon dioxide concentration
4/ Affinity (high/low)
In the lungs, there will be a high concentration of oxygen and a low concentration of carbon dioxide, that will result in a high affinity of haemoglobin to oxygen resulting in oxygen being loading, or associated
Describe the conditions you would expect (specifics below) when oxygen is being unloaded (dissociated) by haemoglobin
CONDITIONS:
1/ Region of body
2/ Oxygen concentration
3/ Carbon dioxide concentration
4/ Affinity (high/low)
In the body’s tissues, there is a low level of oxygen and a high level of carbon dioxide, which results in a low affinity of haemoglobin to oxygen resulting in oxygen being unloaded, dissociated
