Haemoglobin

Question 1

What type of protein is haemoglobin?

Answer 1

A water soluble globular protein

Question 2

What is the maximum structure of haemoglobin?

Answer 2

Quartenary structure

Question 3

What are the polypeptide chains in the quarternary structure of haemoglobin?

Answer 3

• two alpha helix polypeptide chains

- two beta pleated polypeptide chains

Question 4

What is the role of haemoglobin?

Answer 4

Carrying oxygen

Question 5

How does haemoglobin carry oxygen?

Answer 5

The oxygen binds to the haem group

Question 6

What is the haem group?

Answer 6

Fe2+

Question 7

How many oxygen molecules can a haemoglobin carry?

Answer 7

4 O2 molecules

Question 8

How has haemoglobin been evolved?

Answer 8

To make it efficient at loading oxygen under one set of conditions and unloading it at another

Question 9

What is the process by which haemoglobin binds to oxygen?

Answer 9

Loading or associating

Question 10

Where does oxygen association take place in humans?

Answer 10

In the lungs

Question 11

What is the process by which haemoglobin releases its oxygen?

Answer 11

Unloading or dissociation

Question 12

Where does oxygen dissociation take place in humans?

Answer 12

In tissues

Question 13

What do haemoglobins with high oxygen affinity do?

Answer 13

They associate with oxygen easily but struggle to dissociate

Question 14

What do haemoglobins with low oxygen affinity do?

Answer 14

They dissociate with oxygen easily but struggle to associate

Question 15

In order for haemoglobin to be efficient at transporting oxygen what must it do?

Answer 15

• readily associate with oxygen at the gas exchange surface

- readily dissociate from oxygen at tissues

Question 16

What can haemoglobin do to its oxygen affinity?

Answer 16

It can change its affinity under different conditions

Question 17

How does haemoglobin change its oxygen affinity?

Answer 17

It’s shape changes in the presence of certain chemicals (such as carbon dioxide)

Question 18

In the presence of carbon dioxide how does haemoglobin change its shape?

Answer 18

It makes it so the haemoglobin binds more loosely to oxygen causing haemoglobin to release its oxygen

Question 19

What is the oxygen concentration at the gas exchange surface?

Answer 19

High

Question 20

What is the carbon dioxide concentration at the gas exchange surface?

Answer 20

Low

Question 21

What is the affinity of haemoglobin for oxygen at the gas exchange surface?

Answer 21

High

Question 22

Is oxygen associated or dissociated at gas exchange surfaces?

Answer 22

Associated

Question 23

What is the oxygen concentration at the respiring tissues?

Answer 23

Low

Question 24

What is the carbon dioxide concentration at the respiring tissues?

Answer 24

High

Question 25

What is the affinity of haemoglobin for oxygen at the respiring tissues?

Answer 25

Low

Question 26

Is oxygen associated or dissociated at respiring tissues?

Answer 26

Dissociated

Question 27

Does haemoglobin differ between organisms?

Answer 27

Yes

Question 28

How does haemoglobin differ between organisms?

Answer 28

The different haemoglobins take up and release oxygen differently

Question 29

Why do different haemoglobins have different oxygen affinities?

Answer 29

Each species produces a haemoglobin with a slightly different amino acid sequence, therefore the haemoglobins of different species have different tertiary and quarternary structures and therefore different oxygen binding properties