Review A-Level Edexcel Biology translating between data forms through graph comments, comparisons, numerical support and evaluation of evidence limits.
Sickle cell disease is caused by a gene mutation affecting the -globin chain of haemoglobin.
The red blood cells in a person with sickle cell disease are sickle shaped and less elastic. They also have a shorter lifespan than healthy red blood cells.
These sickle shaped red blood cells cannot carry as much oxygen as healthy red blood cells and they get stuck in the capillaries.
The graph shows oxygen dissociation curves for groups of people with sickle cell disease and those without the disease.
The shaded areas represent the range of values for each group of people.
Percentage of haemoglobin saturated with oxygen (\%)
A p50 value is the partial pressure of oxygen that results in 50\% saturation of haemoglobin.
Calculate the largest difference in the p50 values between a person with sickle cell disease and a person without this disease.
Give your answer to an appropriate number of decimal places.