oxygen carriage Flashcards
what does oxygen and haemoglobin produce
oxyhaemoglobin -402+hb - hb(o2)4
what is cooperative binding?
binding of one 02 molecule changes shape of haemoglobin making it easier for another to bind.
what is affinity
how well haemoglobin binds to oxygen.
what is shown on an oxygen dissociation curve
the conc of o2 /partial pressure with the conc of oxygen carried by red blood cells /percentage saturation .
what happens at high partial pressures of oxygen
haemoglobin is being loaded with oxygen.
-carries max amount of o2 molecules.
-haemoglobin is saturated.
what happens at low partial pressures of oxygen-
haemoglobin is being unloaded.
-haemoglobin dissociates and releases oxygen.
why is the curve s shaped.
when haemoglobin releases and 02 molecule it binds/releases a 2nd more quickly. haemoglobin is more efficient at unloading o2 over a range of partial pressures of oxygen.
how are llamas adapted to a low partial pressure environment.
haemoglobin has a higher affinity for all partial pressures and oxygen is loaded in lungs at low partial pressures.
how are lugworms adapted o a low partial pressure
low metabolic rate-little o2 requirement.
-its haemoglobin loads over a range of partial pressures and only unloads at very low pp.
how is foetal haemoglobin adapted to its environment.
has a higher affinity for o2 than adult haemoglobin at same partial pressure. at all partial pressures, oxygen will transfer from maternal to foetus. foetal haemoglobin will become saturated at lower partial pressures than adult haemoglobin. The higher affinity allows it to take oxygen from maternal haemoglobin across the placenta.
what is myoglobin
an oxygen carrying molecule found in muscles and only releases o2 when there is very little oxygen In the muscle.
has a a high affinity for oxygen at very low partial pressures of oxygen so acts as a oxygen store.
what is the bohr effect
as the conc of co2 increases, haemoglobin releases o2 more readily so at all partial pressures of oxygen the haemoglobin is less saturated. the bohr shift moves to right so haemoglobin is more efficient at unloading 02 and delivers oxygen to respiring cells.
what are the 3 ways co2 is transported.
- carried in plasma as hydrogen carbonate ions (HCO3-)(85%)
2.bound to haemoglobin as carbamino-heamoglobin (10%)
3.dissolved in plasma (5%)
how is c02 made into hydrogen carbonate ions
in plasma -slow reaction-no enzyme use
co2 + H20 =carbonic acid
dis dissociates to form a proton and a hydrogen carbonate ion.
in red blood cell the same reaction occurs quickly with the enzyme carbonic anhydrase.
what happens to the proton
combines with oxyhaemoglobin to form haemoglobonic acid. this increases the rate of oxygen release. The removal of H+ ions prevents lowering of PH in blood.
