Haemoglobin

Question 1

Does haemoglobin have a quarternary structure?

Answer 1

Yes, it is a large protein with four polypeptide chains

Question 2

Where is haemoglobin found?

Answer 2

In red blood cells

Question 3

What does each polypeptide chain have?

Answer 3

A haem group which contains an iron ion and gives haemoglobin it’s red colour

Question 4

Does haemoglobin have a higher affinity for oxygen?

Answer 4

Yes, each molecule can carry for oxygen molecules

Question 5

What does oxygen joining haemoglobin form?

Answer 5

Oxyhaemoglobin

Question 6

Is the production of Oxy haemoglobin a reversible reaction?

Answer 6

Yes, when oxygen leaves oxyhaemoglobin it disassociates with it near the body cells and turns back to haemoglobin

Question 7

What is the partial pressure of oxygen?

Answer 7

A measure of oxygen concentration

Question 8

What increases partial pressure?

Answer 8

The greater the concentration of dissolved oxygen in cells the higher the partial pressure

Question 9

What varies depending on the partial pressure of oxygen?

Answer 9

Haemoglobin is affinity for oxygen

Question 10

How does the partial pressure of oxygen affect what haemoglobin does?

Answer 10

• oxygen loads onto haemoglobin to form oxyhaemoglobin where there is a high partial pressure of oxygen
• oxy haemoglobin unloads its oxygen where there is a lower partial pressure of oxygen

Question 11

How does the partial pressure of oxygen vary from the lungs across the body, and how does this let oxygen be transported around the body?

Answer 11

• oxygen enters blood capillaries at the alveoli in the lungs
• Alveoli have a high partial pressure of oxygen so oxygen loads onto haemoglobin to form Oxy haemoglobin
• When cells respire they use up oxygen which lowers the partial pressure, red blood cells deliver Oxy haemoglobin to respiring tissues where it unloads its oxygen
• The haemoglobin then returns to the lungs to pick up more oxygen

Question 12

What happens to the partial pressure of oxygen when cells respire?

Answer 12

It decreases

Question 13

What does haemoglobin do at higher partial pressure of carbon dioxide?

Answer 13

Gives up oxygen more readily

Question 14

During exercise, describe the Bohr effect

Answer 14

• when cells respond, they produce carbon dioxide which raises the partial pressure of CO2
• This increases the rate of oxygen unloading so the disassociation curve shift to the right
• The saturation of blood with oxygen is lower for a given partial pressure of oxygen meaning that more oxygen is released

Question 15

What does haemoglobin have in organisms that live in environment environments with low concentration of oxygen?

Answer 15

Higher affinity for oxygen than human haemoglobin