A gene codes for the ?-polypeptide chain. There are 423 bases in this gene that code
for amino acids. How many amino acids are there in the ?-polypeptide chain?
141;
The haemoglobin in one organism may have a different chemical structure from the
haemoglobin in another organism. Describe how.
Different primary structure/amino acids/different number
of polypeptide chains;
The graph shows oxygen dissociation curves for horse haemoglobin and for llama
haemoglobin. Horses are adapted to live at sea level and llamas are adapted to live in
high mountains.
Use the graph to explain why llamas are better adapted to live in high mo
1. Low partial pressure of oxygen;
2. In lungs;
3. (Llama) haemoglobin able to load more
oxygen/(llama) haemoglobin saturated (at
low/particular partial pressure of oxygen);
4. Higher affinity for oxygen;
The oxygen dissociation curve of the fetus is to the left of that for its mother. Explain
the advantage of this for the fetus.
1. Higher affinity / loads more oxygen;
2. At low/same/high partial pressure/pO2;
3. Oxygen moves from mother/to fetus;
After birth, fetal haemoglobin is replaced with adult haemoglobin. Use the graph to
suggest the advantage of this to the baby.
1. Low affinity / oxygen dissociates;
2. (Oxygen) to respiring
tissues/muscles/cells;
Hereditary persistence of fetal haemoglobin (HPFH) is a condition in which production
of fetal haemoglobin continues into adulthood. Adult haemoglobin is also produced.
People with HPFH do not usually show symptoms. Suggest why
Enough adult Hb produced / enough oxygen
released / idea that curves/affinities/Hb are
similar / more red blood cells produced;
Lugworms live in mud where the partial pressure of oxygen is low. The graph shows
oxygen dissociation curves for a lugworm and for a human. (lugworm is far to the left and more steep)
Explain the advantage to the lugworm of having haemoglobin with a disso
High(er) affinity for oxygen /
absorbs/loads more oxygen;
At lower partial pressure (of
oxygen) / lower pO2;
Haemoglobin is a protein. Explain why a mature red blood cell cannot make haemoglobin.
Because there's no nucleus RNA cannot be made and if there's no mitochondria ATP can't make proteins.
A decrease in the pH of blood plasma reduces the affinity of haemoglobin for oxygen.
(a) (i) Explain how aerobic respiration in cells leads to a change in the pH of blood
plasma.
CO2 is produced (in respiration);
forms carbonic acid / hydrogen ions released;
What is the advantage to tissue cells of a reduction in the affinity of haemoglobin
for oxygen when the plasma pH decreases?
low pH because high rate of respiration;
cells need more O2;
more O2 released / O2 released faster;
Deer mice are small mammals which live in North America. One population lives at
high altitude and another at low altitude. Less oxygen is available at high altitude. The
graph shows the oxygen haemoglobin dissociation curves for the two populations of de
high altitudes have a low partial pressure of O2;
high saturation/affinity of Hb with O2 (at low partial pressure O2);
sufficient/enough O2 supplied to cells / tissues;
Deer mice are small mammals which live in North America. One population lives at
high altitude and another at low altitude. Less oxygen is available at high altitude. The
graph shows the oxygen haemoglobin dissociation curves for the two populations of de
difficult to unload/dissociate O2 (at tissues);
Suggest why values for mean rate of blood flow to the tissues are expressed per kilogram of body mass.
Easy to compare and analyse because the animals are different sizes.
Haemoglobin is a protein with a quaternary structure. What is meant by a quaternary structure?
It has more than one polypeptide chain.
How many polypeptide chains is haemoglobin made of?
4