haemoglobin

what is haemoglobin?

water soluble protein w/ a quaternary structure

→ 4 polypeptides each uniquely folded containing a haem group

what is a haem group?

[Fe]²⁺

how many oxygens can bond to one haemoglobin?

4; one per haem group

what does high partial pressure of oxygen mean?

high concentration of oxygen

high affinity for oxygen meaning?

high likelihood of binding to it

when is oxygen loaded?

when partial pressure is high

when is oxygen unloaded?

when partial pressure is low

what regions have low partial pressure of oxygen?

respiring tissues

→ beneficial as oxygen unloads as required due to higher carbon, and lower oxygen conc.

what is the oxyhemoglobin dissociation curve?

curve showing % of saturated haemoglobin molecules at different partial pressures

what does it mean when the curve is shifted to the left?

oxygen is being loaded

no. saturated molecules increased

typically in alveoli

what does it mean when curve is shifted to the right?

oxygen is being unloaded

no. saturated molecules is lower

bohr effect

typically in alveoli

what’s the bohr effect?

when curve shift to the right because CO2 saturation is higher, so affinity for oxygen is lower

it is lower as the acidity of the CO2 causes the haemoglobin to change shape, marking it harder to bind

what is cooperative binding?

haemoglobin shape changes to make it easier/harder for oxygen to bind

how is the cooperative binding of haemoglobin shown in the curve?

initially hard for first O to bind

once it does, shape changes slightly making it easier for the further oxygens to bind

this sudden increase in binding oxygen as it is now easier, causes a sudden steepness in the curve

do all animals have the same type of haemoglobin?

no, they have dif types, with dif affinities for oxygen, which acts as an adaptation for their environments