Question 1

The graph shows the oxygen dissociation curves for haemoglobin of animals that live at high altitude and animals that live at low altitude.

What explains the oxygen dissociation curve at high altitude?

  A  

haemoglobin has a higher affinity for oxygen


  B  

haemoglobin releases oxygen more readily

  C  

the change in partial pressure of carbon dioxide causes a Bohr effect

  D  

the decrease in percentage of carbon dioxide causes the curve to shift to the left

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Question 2

Haemoglobin can bind to carbon dioxide, carbon monoxide, and oxygen.

Which statement about the binding sites of haemoglobin is correct?

  A  

carbon dioxide and carbon monoxide bind to one site, oxygen binds to a different site

  B  

carbon dioxide and oxygen bind to one site, carbon monoxide binds to a different site

  C  

carbon monoxide and oxygen bind to one site, carbon dioxide binds to a different site

  D  

carbon monoxide, oxygen and carbon dioxide all bind to different sites

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Question 3

Which statement describes the Bohr effect?

  A  

in high partial pressure of oxygen and high partial pressure of carbon dioxide, the affinity of haemoglobin for oxygen increases


  B  

in high partial pressure of oxygen and low partial pressure of carbon dioxide, the affinity of haemoglobin for oxygen decreases

  C  

in low partial pressure of oxygen and high partial pressure of carbon dioxide, the affinity of haemoglobin for oxygen decreases

  D  

in low partial pressure of oxygen and low partial pressure of carbon dioxide, the affinity of haemoglobin for oxygen is unchanged

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Question 4

What is the reason for an increase in red blood cells in humans at high altitudes?

  A  

to compensate for the low percentage saturation of haemoglobin


  B  

to enable haemoglobin to unload more oxygen in the tissues by the Bohr effect

  C  

to ensure that haemoglobin is almost 90% saturated when it reaches the tissues

  D  

to increase the number of mitochondria in the blood for ATP production

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Question 5

Which reactions take place in a capillary in an alveolus?

1 - carbon dioxide + water → carbonic acid

2 - carbon dioxide + haemoglobin → carbaminohaemoglobin

3 - haemoglobinic acid → haemoglobin + hydrogen ions

4 - hydrogencarbonate ions + hydrogen ions → carbon dioxide + water

  A  

1 and 2

  B  

3 and 4

  C  

3 only

  D  

4 only

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Question 6

What is produced by the action of carbonic anhydrase?

  A  

carbaminohaemoglobin


  B  

haemoglobinic acid

  C  

hydrogencarbonate ions

  D  

oxyhaemoglobin

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Question 7

Which two statements about the Bohr effect are correct?

1 - increasing the partial pressure of oxygen increases the percentage of oxyhaemoglobin

2 - decreasing the partial pressure of carbon dioxide decreases the percentage of oxyhaemoglobin

3 - increasing the partial pressure of carbon dioxide shifts the dissociation curve of haemoglobin to the left

4 - in low concentrations of carbon dioxide haemoglobin has a high affinity for oxygen

  A  

1 and 2

  B  

1 and 4

  C  

2 and 3

  D  

3 and 4

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Question 8

How many molecules of oxygen are bound to one molecule of haemoglobin, when it is fully saturated with oxygen?

  A  

1

  B  

2

  C  

4

  D  

8

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Question 9

Which statement describes the structure of haemoglobin?

  A  

each of the four polypeptide chains is combined with an identical haem group


  B  

each polypeptide chain has a quaternary structure

  C  

the quaternary structure of each polypeptide chain contains ionic bonds

  D  

two polypeptide chains contain an alpha haem group and two contain a beta haem group

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Question 10

What is the reaction catalysed by carbonic anhydrase?

  A  

CO2 + H2O→ H2CO3

  B  

CO2 + Hb → HbCO2

  C  

H+ + Hb → HHb

  D  

Hb + 4O2 → HbO8

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Question 11

What is the primary structure of haemoglobin made up of?

  A  

alpha helices

  B  

beta sheets

  C  

polypeptide chains

  D  

haem groups

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Question 12

Which statement best describes cooperative binding in haemoglobin?

  A  

the binding of the first oxygen molecule has no effect on the binding of subsequent oxygen molecules

  B  

the binding of the first oxygen molecule makes it harder for subsequent oxygen molecules to bind

  C  

the binding of the first oxygen molecule makes it easier for subsequent oxygen molecules to bind

  D  

the binding of oxygen molecules is completely independent of other molecules

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Question 13

Why does haemoglobin offload more oxygen into tissues with high metabolism?

  A  

because these tissues have a lower pH

  B  

because these tissues have a higher pH

  C  

because these tissues have a lower temperature

  D  

because these tissues have a higher temperature

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Question 14

What effect does a low pH have on the affinity of haemoglobin for oxygen?

  A  

it increases the affinity

  B  

it decreases the affinity

  C  

it does not affect the affinity

  D  

it reverses the affinity

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Question 15

Haemoglobins with a high affinity for oxygen are characterised by their ability to do what?

  A  

take up oxygen more easily and release it more easily

  B  

take up oxygen more easily but release it less easily

  C  

take up oxygen less easily and release it more easily

  D  

take up oxygen less easily but release it less easily

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