Exchange (HAEMOGLOBIN)

Question 1

Where is haemoglobin found

Answer 1

Within the red blood cells

Question 2

Describe the structure of haemoglobin

Answer 2

Made up of 4 polypeptide chains
4 haem groups within the polypeptide chains. Each haem contains an Iron ion

Question 3

Give the reversible equation for the loading and unloading of oxygen

Answer 3

Haemoglobin + oxygen ⇌ oxyhaemoglobin
Hb + 4O2 ⇌ HbO8

Question 4

Describe the oxygen disassociation curve

Answer 4

Sigmoid (s shaped) curve
Saturation of haemoglobin with oxygen on y axis against partial pressure of oxygen on the x axis

Question 5

Where is there a higher and lower partial pressure of oxygen in the body

Answer 5

High partial pressure of oxygen = lungs
Low partial pressure of oxygen = tissue

Question 6

Describe what happens to haemoglobin at the lungs

Answer 6

At the lungs, haemoglobin has a higher affinity for oxygen as there is a higher partial pressure of oxygen so its loaded onto haemoglobin to form oxyhaemoglobin
Thus oxygen can be transported around the body

Question 7

Describe what happens to haemoglobin at the tissues

Answer 7

At the tissues, haemoglobin has a lower affinity for oxygen due to lower partial pressure of oxygen so oxygen is unloaded from oxyhaemoglobin for aerobic respiration

Question 8

Why is the oxygen disasccoiation curve S shaped and not a straight line

Answer 8

S shaped due to the cooperative nature of oxygen binding. Once the first molecule of oxygen is binded, haemoglobin changes shape so it becomes easier to for the rest of the molecules to join. This results in the steep curve, not straight line.