12.11 Haemoglobin Flashcards
When does oxygen get transported by haemoglobin and not simple diffusion?
For the transport of organisms that are too large for simple diffusion
Affinity definition
Chemical attraction
Saturation definition
Full of oxygen (full load)
Loading definition
Gaining oxygen onto haemoglobin
Unloading definition
Unloading oxygen in haemoglobin to tissues
Partial pressure definition (pO2)
The proportion of oxygen in a mixture of gases or a solution
Where is saturated haemoglobin found?
After it has been to the lungs
Where is unsaturated haemoglobin found?
Before it has passed through the lungs
What is unsaturated haemoglobin needed for?
Aerobind respiration to produce ATP
What is the structure off haemoglobin?
A quaternary structure with four polypeptide chains, each containing a haem group.
What affinity does haemoglobin haver to oxygen?
A high affinity
How many molecules of oxygen can each haemoglobin combine with?
Four oxygen molecules
When oxygen and haemoglobin combing, what is it called?
Oxyhaemoglobin
Percentage saturation of haemoglobin equation
Oxygenated / haemoglobin x 100
Why is the first oxygen molecule important?
The first oxygen molecule alters the tertiary structure, making the binding site easier to bind to oxygen
The more the more the more
The more oxygen is in the blood, the more oxygen is loaded onto haemoglobin, the more saturated there haemoglobin is
What is the name of the partial pressure curve?
Sigmoid curve
What is the partial pressure of oxygen in capillaries?
High
What is the partial pressure of oxygen in respiring tissues?
Lower
Why is the partial pressure of oxygen in respiring tissues lower?
The haemoglobin has a lower affinity to oxygen as the partial pressure is lower o the oxyhaemoglobin starts to break down and unloads the oxygen more easily
What is the oxygen in the tissues used for?
Aerobic respiration
What is the effect of increased respiration on oxygen dissociation?
- Tissue cells respire quickly, using up the dissolved O2 in the surrounding fluid
-This reduces the partial pressure to a lower level
The oxygenated blood arriving with fully saturated haemoglobin will unload more oxygen more easily into the tissue cells - The haemoglobin therefore, will have an even lower affinity to oxygen
What is the Bohr shift?
The sigmoid curve shifts to the right
What is the effect of increased carbon dioxide concentration on the sigmoid curve?
The affinity to oxygen is even lower
The partial pressure to CO2 increases, saturation of haemoglobin decreases
Causing the dissociation curve to shift to the right
Why does haemoglobin have a lower affinity to oxygen at high levels of CO2?
When CO2 dissolves in the blood, it makes it more acidic
Haemoglobin is a protein, so the change in pH alters the tertiary structure of the haemoglobin
Therefore oxygen can’t bind as easily
Heat from respiration helps mammals to maintain a constant body temp
Explain the relationship on the sigmoid curve
Smaller mammals have a larger SA:V ratio, therefore more heat lost per unit body mass and a greater rate of respiration
Oxygen required for aerobic respiration
Haemoglobin releases more oxygen
What can cause differences in haemoglobin affinities?
Genetic differences
Mutations
What type of haemoglobin is found in places of high altitude?
Haemoglobin has a higher affinity to oxygen
Curve shifted to the left
Becomes fully saturated at lower partial pressure
Similar to the fetus curve
What type of haemoglobin curve is found in animals like cheetahs?
Haemoglobin has a lower affinity to oxygen
Curve shifts to the right
Oxygen dissociates from haemoglobin more easily
Oxygen more readily available in respiring tissue cells
Metabolism definition
Rate of cellular reactions
The oxygen dissociation curve of a foetus is to the left of the mothers, explain the advantage
Higher affinity to oxygen at the same partial pressure
Oxygen moves from the mother to foetus more easily
Explain how oxygen is loaded, unloaded and transported in the blood
- Haemoglobin carries oxygen in red blood cells
- Loading takes place in the lungs at a high partial pressure
- Unloading takes place in respiring tissue cells at a low partial pressure
Unloading linked to carbon dioxide concentration
