Haemoglobin And Myogobin

Question 1

How many oxygens does haemoglobin carry?

Answer 1

4

Question 2

Why is sickle cell anaemia prevalent in malaria endemic regions?

Answer 2

Because sickle cell trait provides resistance to severe malaria (Plasmodium Falciparum)

Question 3

What mutation causes sickle cell?

Answer 3

Single gene mutation at codon 7 of beta globin gene. Causes A to T substitution results in change from gluatamate to valine

Question 4

What are thalassemias?

Answer 4

Insufficient production of haemoglobin - either alpha or beta

Question 5

Name 4 potential symptoms of thalassemias

Answer 5

Anaemia
Gall stones
Bony deformities (due to bone marrow expansion)
Jaundice
Splenomegaly
Incompatible with life - still birth

Question 6

How many oxygens does myoglobin carry?

Answer 6

1

Question 7

What is the structure of myoglobin?

Answer 7

Compact structure - 75% alpha helices

Question 8

What shape is the myoglobin saturation curve?

Answer 8

Hyperbolic - saturated very quickly

Question 9

Oxygen binding to haemoglobin stabilises the __________

Answer 9

R state

Question 10

Which state of haemoglobin promotes oxygen binding?

Answer 10

R state - haem groups more exposed - easier for oxygen to bind - high affinity

Question 11

What shape is the haemoglobin saturation occurs?

Answer 11

Sigmoidal

Question 12

What is cooperative binding of oxygen to haemoglobin?

Answer 12

Binding of oxygen to haemoglobin increases binding affinity for the next oxygen

(Binding of first oxygen is hard - low affinity, binding of last oxygen is easy - high affinity)

Question 13

What affect does 2,3 bisphosphoglycerate (BPG) have on oxygen binding to haemoglobin?

Answer 13

Lowers haemoglobin affinity for of oxygen - shifts curve to the right

Question 14

What effect does CO2 and H+ have on haemoglobin PST oxygen binding?

Answer 14

Lower its affinity for oxygen - shift curve to the right

Question 15

What is the Bohr effect?

Answer 15

States that haemoglobins binding affinity for oxygen is inversely proportional to acidity
(As H+ concentration increases oxygen affinity decreases)

Question 16

What effect does CO have on oxygen binding by haemoglobin?

Answer 16

CO binds very tightly to haemoglobin and myoglobin - blocks oxygen binding.

Fatal if 2 or more CO bind haemoglobin

Question 17

What is foetal haemoglobin?

Answer 17

Contains 2 alpha and 2 gamma subunits.
Has higher affinity for oxygen than maternal (shifts curve to the left) which allows transfer of oxygen from maternal blood to foetal blood