Miss Jenkins Res 1 Flashcards
What structure does it form
Quaternary structure
How has haemoglobin evolved
Evolved to make it efficient it’s loading oxygen in one set of condition and and unloading it in another
Difference between primary and secondary structure
Primary= sequence of amino acids
Secondary= when polypeptide chains coiled into a helix
Why does it have a quaternary structure
When all 4 polypeptides are linked together. Each associated with a haem group and contains a fe2+ ion
Role of heamoglobin
Transport oxygen, should readily associate and dissociate with oxygen when needed.
Differences in haemoglobin
Different amino acid sequence so slightly different tertiary and quaternary structure/ different oxygen binding properties
What is partial pressure
Pressure exerted by a single component of gas
What happens after the first oxygen binds to the heamoglobin
Changes the quaternary structure, changes shape, easier for other subunits to bind to oxygen
What is positive cooperativity
Binding of the first molecule makes binding of the second one more easier
Why is it harder for the fourth oxygen to bind
Most of the sites are taken up by the other oxygens so its harder to bind
What is the Bohr effect
The greater the concentration of CO2, the more readily the haemoglobin releases its oxygen
What does CO2 do to haemoglobin in high amounts
In rapidly respiring tissues (e.g., muscles), the concentration of carbon dioxide is high. The affinity of haemoglobin for oxygen is reduced, which, coupled with the low concentration of oxygen in the muscles, means that oxygen is readily un loaded from the haemoglobin into the muscle cells. The increased carbon dioxide concentration has shifted the oxygen dissociation curve to the right
Process of transportation
The pH is slightly raised due to the low concentration of
carbon dioxide.
• The higher pH changes the shape of haemoglobin int0 one that
enables it tO load oxygen readily.
• This shape also increases the affinity of haemoglobin for oxygen, so
it is not released while being transported in the blood to the tissues.
• In the tissues, ca rbon dioxide is produced by respiring cells.
• Carbon dioxide is acidic in solution, so rhc pH of the blood within
the the tissues is lowered.
• The lower pH changes the shape of haemoglobin into one with a
lower affinity for oxygen.
• Haemoglobin releases its oxygen into the respiring tissues.
What percentage of heamoglobin under normal conditions still have oxygen
75%
Y do large organisms have a transport system
Low Sa:V ratio
High diffusion distance
Activeness of organism
