Transport of Oxygen by Haemoglobin

Question 1

what is the structure of haemoglobin

Answer 1

a quaternary structure protein
- haem group > iron > red pigment > this is where O2 binds
- 4 polypeptide chains
1 haemoglobin = 4 oxygen molecules

Question 2

what is affinity

Answer 2

the likelihood of a molecule binding to another

Question 3

whats does the affinity of haemoglobin for oxygen mean

Answer 3

the ability of haemoglobin to bind to oxygen

Question 4

what is the saturation of haemoglobin with oxygen referring to

Answer 4

when haemoglobin is holding the maximum amount of oxygen that it can bind

Question 5

what does loading / association refer to

Answer 5

the binding of oxygen to haemoglobin

Question 6

what does unloading / dissoaciation refer to

Answer 6

to unbinding of oxygen to haemoglobin

Question 7

what does a high partial pressure mean

Answer 7

a high concentration of

Question 8

why is the unbinding of haemoglobin and oxygen beneficial at areas of low partial pressure of oxygen

Answer 8

if theres a low partial pressure it means that oxygen is being used (e.g. respiring cells) so if oxygen is unblinded it means that it can be used where needed (e.g. for aerobic respiration)

Question 9

explain cooperative binding of haemoglobin

Answer 9

once the first oxygen binds, the structure of haemoglobin slightly changes enabling easier binding of the subsequent oxygen molecules

Question 10

explain the Bohr effect

Answer 10

• higher pCO2 means the dissociation curve shifts to the right
• this is because the rate of oxy haemoglobin unbinding has increased > unbinds faster to produce Haemoglobin and oxygen

Question 11

if the dissociation curve is further left it means …

Answer 11

that haemoglobin has a higher affinity for oxygen

Question 12

if the dissociation curve shifts further to the right it means …

Answer 12

that the affinity of haemoglobin for oxygen is lower

Question 13

what type of haemoglobin is needed at low oxygen environments

Answer 13

haemoglobin with a higher affinity for oxygen because much oxygen is not available so haemoglobin has to be good at binding to oxygen

Question 14

what type of haemoglobin do organisms with high activity levels have and why

Answer 14

haemoglobin with a lower affinity for oxygen because the organism needs the haemoglobin to easily unload any oxygen it has so they can use it for themselves

Question 15

what type of haemoglobin do smaller animals need

Answer 15

smaller animals = larger SA:V ratio so they lose heat quickly so higher metabolic rate
they require haemoglobin with a low affinity for oxygen so the oxygen can be used for the organism