Respiratory Pigments Flashcards
What type of proteins are respiratory pigments?
Metalloproteins (proteins with a metal element)
What do respiratory pigments do?
Bind reversibly with oxygen at specific sites
What are the four major respiratory pigments in the animal kingdom?
Haemoglobin
Haemeryrhrin
Haemocyanin
Chlorocruorins
What affects the percentage of oxygen that can bind to the respiratory pigment?
Partial pressure of oxygen
How many subunits are there in haemoglobin?
4
What happens when the shape of haemoglobin changes?
The affinity for oxygen increases so attracts more oxygen
Explains sigmoid shape of dissociation curve
What happens at a low partial pressure of oxygen?
Haemoglobin’s affinity for oxygen is reduced and the oxygen is dissociated (usually to respiring tissues)
What is the oxygen affinity in anaerobic conditions?
High
What is another respiratory pigment found in the muscles?
Myoglobin (has very high affinity in order to extract oxygen from the blood)
How does temperature effect oxygen affinity?
At a higher temperature there is a lower affinity and oxygen is unloaded more readily
What is the shift in a dissociation curve called?
Bohr shift
What is root shift?
Only happens in teleost fish
Acidity decreases the maximum capacity of oxygen, not just affinity, so released more oxygen to the tissues
How is carbon dioxide transported?
As bicarbonate ions
What catalysed the reaction of CO2 to bicarbonate ions?
Carbonic Anhydrase
