02 Dissociating Curves

Question 1

Loading

Answer 1

• Loading/associating – the ability of oxygen to bind to haemoglobin

Question 2

Unloading

Answer 2

Unloading/dissociating – the ability of oxygen to be released from haemoglobin

Question 3

Affinity

Answer 3

Affinity? – the likelihood O2 will bind to haemoglobin (higher affinity = more associating)

Question 4

Bohr shift- simple

Answer 4

Bohr shift/effect? – the impact of CO2 on haemoglobin

Question 5

Partial pressure

Answer 5

Partial Pressure – fancy way of saying concentration of a gas e.g. oxygen

Question 6

Co operative binding

Answer 6

• As O2 loads to oxygen, its binding cause the haemoglobin to change shape
• This change of shape makes it easier for more oxygen to load
• Until all the haem groups are occupied and the haemoglobin is saturated (full)
• This is called co-operative binding

Question 7

Foetal haemoglobin

Answer 7

• Mammal foetuses do not have functioning lungs
• Foetal Hb must have a higher O2 affinity than maternal Hb
• The foetus has to be able to load/associate with O2 in an area when the mother will unload/ dissociate with O2
• This happens in the placenta

Question 8

Bohr shift In-depth description

Answer 8

• In exercising or organisms with high metabolism
• CO2 in tissues reduces the affinity of oxygen to haemoglobin (it’s acidic/changes Hb shape)
• In tissues where there is lots of respiration the oxygen is more easily unloaded – this makes the curve shift to the right.
• This can replace used O2 easier
• The impact of CO2 is called the Bohr Shift

Question 9

Factors affecting oxygen dissociation

Answer 9

Location – higher altitudes have lower partial pressure of O2, curve shifts left
Activity – More CO2 production, curve shifts right
Size – Smaller mammals have higher metabolism, curve will shift right

Question 10

When oxygen binds to haemoglobin what is produced? (1)

Answer 10

• Oxyhaemoglobin