Haemoglobin and Oxygen Dissociation Exam Questions
and Answers 2023 with complete solution
1. quaternary structure
2. haem group binds oxygen
3. four polypeptide chains so four haem groups
4. one haemoglobin molecule can bind 4 oxygen molecules
5. reference to allosteric effect/ cooperative binding
6. reference to Bohr effect/ oxygen release on binding hydrogen ions
Describe how the structure of haemoglobin makes it effective in the transport of oxygen
(4/6)
1. haemoglobin carries oxygen/ has high affinity for oxygen
2. loading/ uptake in the lungs
3. at high partial pressure of oxygen
4. unloads/ dissociates/ releases oxygen at respiring cells/tissues
5. at low partial pressures of oxygen
6. unloading linked to higher CO2 concentration at respiring tissues
Explain how oxygen is loaded, transported and unloaded in the blood (6/7)
1. in exercise there is a faster respiration rate
2. more CO2 produced
3. CO2 is acidic/ forms carbonic acid
4. lactic acid production
5. release of H+ ions = fall in pH (becomes more acidic)
The blood leaving a muscle has a lower pH than the blood entering it. During vigorous
exercise, the fall in pH is even greater. Explain what causes this greater fall in pH (4/5)
1. diffusion of oxygen into red blood cells
2. haemoglobin has high affinity for oxygen where there is a high O2 concentration
3. therefore loads/ becomes saturated in lungs/ where oxygen is abundant
4. oxyhaemoglobin formed
5. reference to the role of haem
6. unload/ low affinity in low oxygen concentrations
7. explanation of dissociation curve
8. respiration at tissues gives high Co2 concentration
9. dissociation curve shifts to the right
Describe how haemoglobin is involved i absorbing oxygen in the lungs and transporting
it to respiring tissues (6/9)
1. fetal haemoglobin has greater affinity for oxygen
2. at the same partial pressures of oxygen
3. (any correct figures from a graph displayed)
4. maintains diffusion gradient across placenta
Explain how fetal haemoglobin makes it possible for the fetus to take oxygen from the
mothers blood (4)
1. at the tissues with a low partial pressure of oxygen the shrews haemoglobin is less
saturated with oxygen
2. has reduced affinity
, 3. oxyhaemoglobin dissociates more readily
4. more oxygen released
5. allowing the shrew to meet the greater respiration demand/rate
There is an advantage to the shrew in having haemoglobin with a dissociation curve
shifted to the right. Explain this advantage (5)
1. able to be saturated with oxygen in very low concentrations
2. related to low oxygen concentration in environment
3. able to unload only at a slightly lower oxygen concentration
Explain the advantage to the lugworm of having the dissociation curve to the right given
that it lives in an area with low oxygen levels (3)
1. Hb has a higher affinity for oxygen
2. becomes saturated at lower partial pressures
3. able to supply enough oxygen to the tissues
QP Q1a) The graph shows the oxygen haemoglobin dissociation curves for three
species of fish.
Species A lives in water containing a low partial pressure of oxygen. Species C lives in
water with a high partial pressure of oxygen. The oxygen haemoglobin dissociation
curve for species A is to the left of the curve for species C.
Explain the advantage to species A of having a dissociation curve in this position (3)
(draw the graph - species B dissociation curve is in the middle)
1. fish B has a greater respiration rate
2. Hb dissociates more readily than for fish A (lower affinity)
3. more O2 supplied to meet increased respiration rate
QP Q1) The graph shows the oxygen haemoglobin dissociation curves for three species
of fish.
Species A lives in water containing a low partial pressure of oxygen. Species C lives in
water with a high partial pressure of oxygen. The oxygen haemoglobin dissociation
curve for species A is to the left of the curve for species C.
b)Species A and B live in the same place but B is more active. Suggest an advantage to
B of having an oxygen haemoglobin dissociation curve to the right of that for A (2)
(draw the graph)
1. red blood cell - does not contain ribosomes, no cell wall, no capsule, no flagellum, no
mesosomes, no plasmid, no genetic material
2. bacterial cell - contains ribosomes, cell wall, capsule, flagellum, mesosmes, plasmid,
genetic material
QP Q2) Read the following passage
A red blood cell is packed full of haemoglobin. When mature, it contains none of the
organelles usually found in an animal cell. The nucleus, endoplasmic reticulum,
mitochondria and ribosomes are all absent.
More is known about the plasma cell of a human red blood cell than about any other
eukaryotic cell membrane. One reason for this is that the plasma membrane
and Answers 2023 with complete solution
1. quaternary structure
2. haem group binds oxygen
3. four polypeptide chains so four haem groups
4. one haemoglobin molecule can bind 4 oxygen molecules
5. reference to allosteric effect/ cooperative binding
6. reference to Bohr effect/ oxygen release on binding hydrogen ions
Describe how the structure of haemoglobin makes it effective in the transport of oxygen
(4/6)
1. haemoglobin carries oxygen/ has high affinity for oxygen
2. loading/ uptake in the lungs
3. at high partial pressure of oxygen
4. unloads/ dissociates/ releases oxygen at respiring cells/tissues
5. at low partial pressures of oxygen
6. unloading linked to higher CO2 concentration at respiring tissues
Explain how oxygen is loaded, transported and unloaded in the blood (6/7)
1. in exercise there is a faster respiration rate
2. more CO2 produced
3. CO2 is acidic/ forms carbonic acid
4. lactic acid production
5. release of H+ ions = fall in pH (becomes more acidic)
The blood leaving a muscle has a lower pH than the blood entering it. During vigorous
exercise, the fall in pH is even greater. Explain what causes this greater fall in pH (4/5)
1. diffusion of oxygen into red blood cells
2. haemoglobin has high affinity for oxygen where there is a high O2 concentration
3. therefore loads/ becomes saturated in lungs/ where oxygen is abundant
4. oxyhaemoglobin formed
5. reference to the role of haem
6. unload/ low affinity in low oxygen concentrations
7. explanation of dissociation curve
8. respiration at tissues gives high Co2 concentration
9. dissociation curve shifts to the right
Describe how haemoglobin is involved i absorbing oxygen in the lungs and transporting
it to respiring tissues (6/9)
1. fetal haemoglobin has greater affinity for oxygen
2. at the same partial pressures of oxygen
3. (any correct figures from a graph displayed)
4. maintains diffusion gradient across placenta
Explain how fetal haemoglobin makes it possible for the fetus to take oxygen from the
mothers blood (4)
1. at the tissues with a low partial pressure of oxygen the shrews haemoglobin is less
saturated with oxygen
2. has reduced affinity
, 3. oxyhaemoglobin dissociates more readily
4. more oxygen released
5. allowing the shrew to meet the greater respiration demand/rate
There is an advantage to the shrew in having haemoglobin with a dissociation curve
shifted to the right. Explain this advantage (5)
1. able to be saturated with oxygen in very low concentrations
2. related to low oxygen concentration in environment
3. able to unload only at a slightly lower oxygen concentration
Explain the advantage to the lugworm of having the dissociation curve to the right given
that it lives in an area with low oxygen levels (3)
1. Hb has a higher affinity for oxygen
2. becomes saturated at lower partial pressures
3. able to supply enough oxygen to the tissues
QP Q1a) The graph shows the oxygen haemoglobin dissociation curves for three
species of fish.
Species A lives in water containing a low partial pressure of oxygen. Species C lives in
water with a high partial pressure of oxygen. The oxygen haemoglobin dissociation
curve for species A is to the left of the curve for species C.
Explain the advantage to species A of having a dissociation curve in this position (3)
(draw the graph - species B dissociation curve is in the middle)
1. fish B has a greater respiration rate
2. Hb dissociates more readily than for fish A (lower affinity)
3. more O2 supplied to meet increased respiration rate
QP Q1) The graph shows the oxygen haemoglobin dissociation curves for three species
of fish.
Species A lives in water containing a low partial pressure of oxygen. Species C lives in
water with a high partial pressure of oxygen. The oxygen haemoglobin dissociation
curve for species A is to the left of the curve for species C.
b)Species A and B live in the same place but B is more active. Suggest an advantage to
B of having an oxygen haemoglobin dissociation curve to the right of that for A (2)
(draw the graph)
1. red blood cell - does not contain ribosomes, no cell wall, no capsule, no flagellum, no
mesosomes, no plasmid, no genetic material
2. bacterial cell - contains ribosomes, cell wall, capsule, flagellum, mesosmes, plasmid,
genetic material
QP Q2) Read the following passage
A red blood cell is packed full of haemoglobin. When mature, it contains none of the
organelles usually found in an animal cell. The nucleus, endoplasmic reticulum,
mitochondria and ribosomes are all absent.
More is known about the plasma cell of a human red blood cell than about any other
eukaryotic cell membrane. One reason for this is that the plasma membrane
