A5 Haemoglobin and oxygen dissociation curves Flashcards
Name the graph shown on the diagram
Oxygen dissocation curve
Name the inorganic ion found in haemoglobin
Iron
Found in the haem group
Describe the structure of haemoglobin
Globular protein.
Quaternary structure - consists of 4 polypeptide chains.
Each polypeptide contains a haem group.
Describe the role of haemoglobin
Found in red blood cells.
Binds to oxygen to form oxyhaemoglobin
Carries oxygen around the body to the respiring tissues.
How does the partial pressure of carbon dioxide affect the binding of oxygen to haemoglobin?
Carbon dioxide dissolves in blood plasma to form (carbonic) acid.
Causes the pH to drop.
Haemoglobin changes shape slightly.
Affinity for oxygen decreases.
More oxygen is released from the haemoglobin.
Known as the Bohr effect
Why does oxygen binds to haemoglobin in the lungs?
Partial pressure of oxygen is high
Haemoglobin has a high affinity for oxygen.
Oxygen diffuses into the red blood cell and binds to haemoglobin
Why is oxygen released from the haemoglobin in respiring tissues?
Partial pressure of oxygen is low.
Partial pressure of carbon dioxide is high due to respiring tissues
Affinity for oxygen decreases
Oxygen is released to the respiring tissues.
People living at high altitudes have more red blood cells than
people living at sea level.
Explain the advantage of this.
Partial pressure of oxygen is lower in the air.
More red blood cells
More haemoglobin
Carry more oxygen to tissues
During exercise the oxygen dissociation curve moves to the right
. Explain the advantage of this.
Haemoglobin releases more oxygen to the muscles.
Aerobic respiration maintained releasing more energy for muscle contraction
Describe where haemoglobin loads and unloads oxygen in the body
Haemoglobin picks up oxygen at high partial pressure eg in the lungs
Haemoglobin unloads oxygen at low partial pressures eg in respiring tissues
What is cooperative binding in haemoglobin?
Difficult for the first oxygen molecule to bind to haemoglobin.
Binding of first oxygen changes the tertiary structure of the haemoglobin
The position of the haem groups shift and allows the next two oxygen molecules to bind more easily.
Name the effect shown on the graph
Bohr effect
