Year 12 - Haemoglobin

Question 1

Describe and explain cooperative bonding

Answer 1

At low partial pressure of oxygen, little increase in saturation as oxygen increases.​

Binding of first oxygen changes tertiary structure​

Uncovering another oxygen binding site. ​

Rapid rise (in saturation of haemoglobin with oxygen) ​

As it gets easier for oxygen to bind.

Question 2

Define partial pressure

Answer 2

It is a measure of the concentration of a gas in a mixture of gases or a liquid.

Question 3

Explain what is meant when an oxygen dissociation curve is to the right of the normal curve

Answer 3

Metabolic reactions in tissues causes increased respiration rate. ​

Increased CO2 production ​

Dissolves in blood as carbonic acid​

Causes lowering of blood pH​

Increased acidity ​

Changes haemoglobin tertiary structure ​

Haemoglobin unloads more oxygen more readily to respiring tissue at the same partial pressure of oxygen. ​

So more oxygen for more aerobic respiration during exercise/low ppO2 in tissues

Question 4

Describe and explain how organism A is adapted for life in lower partial pressures of oxygen relative to organism B

Answer 4

Organism A haemoglobin has a higher affinity for oxygen than B. ​

associates with oxygen more readily​

So becomes more saturated at same partial pressure of O2. ​

Able to supply enough O2 to tissues ​

O2 used for aerobic respiration​

Prevents anaerobic respiration

Question 5

Describe the advantage of having a lower affinity for oxygen in a disease where more respiration is required.

Answer 5

Haemoglobin type 2 has a lower affinity for oxygen than type 1.​

Unloads oxygen more readily ​

Releasing more oxygen quicker to tissues​

Oxygen used for aerobic respiration ​

Allowing greater respiration rate meeting demand for ATP