Haemoglobin and Oxygen Transport

Question 1

What is Haemoglobin?

Answer 1

A large globular protein with quartnary structure. They have a Haem group which contains an iron ion. Each molecule binds up to 4 oxygen molecules

Question 2

What is Oxyhaemoglobin?

Answer 2

When oxygen associates with haemoglobin

Question 3

What is the equation of Haemoglobin?

Answer 3

Hb + 4O2 = HbO8

Question 4

What are the conditions for Haemoglobin’affinity for Oxygen?

Answer 4

The partial pressure of oxygen
Haemoglobin Saturation
The partial pressure of carbon dioxide

Question 5

What is the partial pressure?

Answer 5

A gas is a measure of concentration of that gas in a mixture of gases or in a liquid

Question 6

What is the partial pressure based on?

Answer 6

How much pressure that gas contributes to the overall pressure exerted by the mixture of gases

Question 7

What happens when the partial pressure for oxygen is high?

Answer 7

Haemoglobin will have a higher affinity for O2

Question 8

What happens when the partial pressure for oxygen is low?

Answer 8

Haemoglobin will have a lower affinity

Question 9

What does the partial pressure ensure?

Answer 9

Oxygen is always picked up by red blood cells in the lungs and released in respiring cells where it is needed

Question 10

Why does the Saturation of Haemoglobin affect the affinity of Oxygen?

Answer 10

Each oxygen molecule binds it changes the shape of the haemoglobin in a way that makes it easier for further oxygen molecules to bind

Question 11

What happens when the Saturation of Haemoglobin increases and what does it mean?

Answer 11

It becomes harder for the final oxygen molecules to bind. This means the Saturation of Haemoglobin with increasing pO2 is not linear

Question 12

what does the Dissociation curve show?

Answer 12

A steep section in the middle where it is easy for oxygen to bind as pO2 increases and shallow gradients at low and high pO2 where it is harder for oxygen to bind.

Question 13

How does the partial pressure of carbon dioxide affect the affinity of Haemoglobin for oxygen?

Answer 13

When the pCO2 is high oxygen Dissociaties from Haemoglobin more easily, this allows more oxygen to be unloaded to cells during intense activity.

Question 14

What does an increase in carbon dioxide production lead to?

Answer 14

A decrease in blood pH as it reacts with water to form carbonic acid.

Question 15

What is the Bohr Effect?

Answer 15

The low pH causes the tertiary structure of the haemoglobin to be altered, decreasing it’s affinity for Oxygen so increasing the Dissociation of oxygen

Question 16

What is the Bohr shift?

Answer 16

An increase in CO2 or a decrease in pH shifts the normal oxygen Dissociation curve to the right

Question 17

What does the Bohr shift show and ensure?

Answer 17

Shows that got the same pO2, the Saturation of blood with oxygen is lower as more oxygen is being released from the haemoglobin
ensure that where there is the most respiration occurring, more oxygen will be released to help maintain the level of metabolic activity

Question 18

What can the high affinity do for the Foetus in the womb?

Answer 18

Oxygen binds to Foetus haemoglobin more easily and is more reluctant to dissociate
The foetal haemoglobin steals the oxygen away from the mother’s haemoglobin when they pass in the placenta

Question 19

What does the high affinity for organisms living in low oxygen environments do?

Answer 19

When there isn’t much oxygen available, the haemoglobin has to be able to load more oxyegn at lower pO2 T make sure enough oxygen is absorbed

Question 20

What does low affinity for small organisms with high SA:V or organisms with high metabolism rate do?

Answer 20

Small mammals with high SA:V lost heat more quickly so they have a high metabolic rate to help maintain their body temperature
Higher metabolic rate= more respiration= greater oxygen demand
The organisms need haemoglobin with a lower affinity for Oxygen as they nerd it to easily unload oxygen to meet their high oxygen demand and allow faster respiration rate