Higer oxygen affinities Flashcards
How does the feotus receive materials
Placenta organ
How are materials exchanged between the mother and foetus
Blood of the mother flows very closely to that of the foetus to allow exchange via diffusion
Limitation of feotus being fully reliant on mothers blood to absorb O2
The mothers blood will never be fully oxygenated when it reaches the placenta, restricting the O2 the foetus receives
Is the percentage saturation of foetus’ blood higher or lower than that of the mother
higher
How is a high saturation achieved by the foetus
Foetal haemoglobin has a slightly different structure to adult
Has a greater affinity for O2 than the mother’s
What is the position of the sigmoid curve of foetal haemoglobin compared to adult
shifted to the left
Myoglobin?
Oxygen binding protein
Intracellular oxygen storage
Abbreviation for myoglobin
Mb
Benefit of myoglobin being intracellular O2 storage 2
Allows organisms to hold their breath for extended periods of time
Increases endurance
Structure of myoglobin
1 subunit (polypeptide chain)
1 haem group
Much higher affinity for O2 than Hb
What does myoglobin having very high affinity for O2 mean for the dissociation of O2
Oxymyoglobin does not dissociate unless the ppO2 is very low e.g in exercising muscle
Where is myoglobin found
Skeletal muscle
Increasing order of O2 affinity
Adult Hb
Fetal Hb
Myoglobin
Physiological adaptations of organisms living at high altitudes (llama)
RBC count increased
Hb has higher affinity for O2 (dissociation curve is shifted left)
Habitat of lugworm
Buries in the sand: low O2 environment
At low tide H2O brings in fresh supply of O2
Adaptations of lugworm
Low metabolic rate
Pumps sea water through burrow to access the limited O2 present
Hb has higher affinity for O2
What is the rationale behind the biconcave shape of RBC
compromise between a sphere (max volume) and a flat disc ( max surface area)
Why are RBC smooth and flexible
So they can flow through capillaries
What % of O2 that diffuses into the capillaries front he lungs is carried as oxyhaemoglobin
98%
What is the name for the induced shape change of the haemoglobin when O2 molecules bind
The structure is relaxed, undergoing conformational change
How to calculate %saturation of haemoglobin
Number of occupied binding sites ÷ total number of binding sites
Does myoglobin have a sigmoid curve on the O2 dissociation graph
No, bc it only has one subunit, so one binding site so there is no opportunity for cooperative binding
What is the dissociation of O2 like in very active animals
Haemoglobin dissociate its O2 at relatively high ppO2 bc their muscle cells respite rapidly so need a lot of O2
What are the characteristics of organisms with a high myoglobin count
Highly active e.g fly long distances
Need to hold breath e.g whales, seals
