Haemoglobin And Oxygen Disassociation Flashcards
Affinity
How likely oxygen will be picked up
Saturation
How much oxygen will be carried (max 4)
Partial pressure
The percentage of oxygen in oxyhaemoglobin
What are the stages of oxygen association
1.adding oxygen changes the shape of the haem group
2. Large surface area means haem groups are easier to join
3. Etc.
4. Harder to join haem group changes shape
Haemoglobin us saturated
What is the Bohr effect?
CO2 displaces oxygen and lowers percentage saturation
Effects haemoglobins affinity for oxygen
CO2 = red blood cells more acidic
Lower PH = Decrease in affinity for oxygen
What is the type of curve that the oxygen dissociation graph shows?
Sigmoidal curve
What are the properties of haemoglobin?
Globular proteins
Quaternary structure = 4 polypeptide chains
1. Readily associate oxygen-> lungs
2. Readily disassociate oxygen -> tissues
(To do this haemoglobin changes shape)
What happens when the curve shifts to the right?
Lower affinity Less haemoglobin is saturated Oxygen binds less readily Oxygen disassociate more readily (From haemoglobin) Allows for a greater respiration rate MORE CO2
What happens on the curve shifts to the left?
A higher affinity More haemoglobin is saturated at a lower partial pressure Oxygen binds more readily Oxygen disassociate less readily Supplies more oxygen to tissues
Low Oxygen animals (high altitudes)
Shift to the right
Lower affinity
More oxygen released into tissues
High oxygen animal (lots of movement)
Shifts left
Higher affinity
More oxygen in the lungs
what is foetal haemoglobin?
Curve left of the mother
To absorb oxygen from mothers blood
What is myoglobin?
A single polypeptide chain found in skeletal muscle
Used as a store of oxygen and is only used at the very low partial pressures
Allows aerobic respiration for longer
What is Fick’s law?
The rate of diffusion is proportional to…
Distance
Features of specialised exchange surfaces
Large surface area to volume ratio Very thin = short diffusion pathway partially permeable =allows selected materials to move across without obstruction Movement of environmental medium Movement of internal medium (maintain a diffusion gradient)
