Haemoglobin

• What is the role of haemoglobin?

  To transport oxygen in the blood
• What is formed when oxygen is loaded onto haemoglobin?

  Oxyhaemoglobin
• How does haemoglobin's affinity for oxygen vary?

  It varies depending on environmental conditions
• What does partial pressure of oxygen (pO₂) measure?

  Oxygen concentration in the environment
• How does increased pO₂ affect haemoglobin's affinity for oxygen?

  It increases haemoglobin's affinity for oxygen
• What happens to haemoglobin's shape when it binds with oxygen?

  Its shape alters to facilitate more binding
• Why is the dissociation curve of haemoglobin not straight?

  Because of cooperative binding of oxygen molecules
• What does a left-shifted dissociation curve indicate?

  Higher affinity for oxygen at low pO₂
• What type of haemoglobin is found in muscles?

  Myoglobin
• How does high altitude affect haemoglobin's affinity for oxygen?

  It increases haemoglobin's affinity for oxygen
• Why do organisms with high activity levels have lower affinity haemoglobin?

  To readily unload oxygen at its site of use
• What is the significance of the dissociation curve in oxygen transport?

  It shows the saturation of haemoglobin with oxygen
• How do you read values from a dissociation curve?

  1. Draw a line from the data point to the curve.
  2. Draw a line parallel to the y-axis.
  3. Read the saturation value from the y-axis.
  4. Calculate differences between saturation values.
• What is the effect of carbon dioxide concentration on haemoglobin?

  It affects the ability to load and unload oxygen
• What happens to the dissociation curve when oxygen availability decreases?

  The curve shifts to the left
• Where is haemoglobin found in humans?

  In red blood cells
• How many polypeptide chains does a haemoglobin molecule have?

  Four polypeptide chains
• What is meant by haemoglobin 'loading' and 'unloading' oxygen?

  Loading is binding oxygen; unloading is releasing it
• Why does a single oxygen molecule increase haemoglobin's affinity for oxygen?

  It causes a conformational change in haemoglobin
• Where in the body would you find cells with a high pO₂?

  In the lungs where oxygen is absorbed
• What are the differences in haemoglobin types based on environmental conditions?

  • High altitude: High affinity for oxygen
  • Low oxygen environments: Left-shifted dissociation curve
  • High activity levels: Lower affinity for oxygen
• What are the practice questions related to haemoglobin's function?

  1. Explain the effect of exercise on dissociation curves.
  2. Match animals to their dissociation curves.
  3. Recall the role and structure of haemoglobin.