haemoglobin

Question 1

98% of the cytoplasmic protein is

Answer 1

Haemoglobin

Question 2

what type of protein is Haemoglobin

Answer 2

metalloprotein

Question 3

what is the structure of haemoglobin

Answer 3

heterodimeric tetramer

2 beta chains 2 alpha chains

Question 4

iron is chelated into protoporphyrin IX by

Answer 4

ferrochelatase to form the final molecule haem

Question 5

ferrochelast incorporates iron into ….

Answer 5

haem subunits

Question 6

Haem is located towards the

Answer 6

periphery of the globin chains

Question 7

Haemogloobin binds oxygen via

Answer 7

Fe 2+

Question 8

haemoglobin transports nitric oxide

Answer 8

via thiol groups

Question 9

Transports CO2 =

Answer 9

carbaminohaemoglobin

Question 10

when oxygen dissocation curve moved to right

Answer 10

affinity is decreased

Question 11

2,3 is the major regulator of

Answer 11

02 affinity

Question 12

2.3 is the intermediate product of

Answer 12

glycolysis

Question 13

2,3DPG binds to

Answer 13

deoxyhaemoglobin in a 1:1 ratio

Question 14

2,3 DPG stabilises ….

Answer 14

the quaternary structure of Hb via -chains

Question 15

2.3 DPG Changes Hb from an R state

Answer 15

to T state

Question 16

2,3DPG is released at high …

Answer 16

po2

Question 17

The bohr effect is

Answer 17

The effect of pH on Hb-oxygen affinity

Question 18

Is HB and impornant buffer

Answer 18

yes

Question 19

Proton accepted when

Answer 19

oxygen released

Question 20

Lactic acid and CO2 increase

Answer 20

[H+]

Question 21

Raised [H+] causes reduced oxygen affinity for Hb, releasing more

Answer 21

oxygen to tissues

Question 22

Two α and β chains form dimers through

Answer 22

low energy non-covalent bonds

Question 23

Low energy bonds promote specific 3D structure comprising

Answer 23

A-H α helices

Non-α-helical segments

Question 24

what does f8 (proximal histidine ))

Answer 24

binds iron)

Question 25

E7 distal histidine binds

Answer 25

oxygen

Question 26

So what happens to the proximal F8 histidine

Answer 26

In its resting state the ferrous iron is out of plane with the F8 histidine – approx 8° or 0.4-0.6A.
Binding of oxygen alters the structure of the haem moiety.
Haem reorientation leads to the movement of iron into the plane of the F8 histidine.
Breakage of hydrogen bonds leads to conformational modification.

Question 27

the folded chains place iron near the exterior so

Answer 27

readily accessible to oxygen

Question 28

Each subunit contains a haem

Answer 28

moiety

Question 29

At the centre of the haem moiety is

Answer 29

iron

Question 30

E7 Histidine binds oxygen in

Answer 30

oxyhaemoglobin

Question 31

Hydrophobic pocket protects Fe2+ from

Answer 31

oxidation.

Question 32

Chromosome 16 =

Answer 32

α-like gene cluster

Question 33

Chromosome 11

Answer 33

β-like gene cluster

Question 34

Main adult haemoglobin HbA is most efficient at carrying

Answer 34

oxygen

Question 35

Alterations in globin chain expression can be associated with

Answer 35

disease

Question 36

Carboxyhaemoglobin

Hb plus carbon monoxide affinity is 281x greater than

Answer 36

oxygen

Question 37

Carboxyhaemoglobin does not bind

Answer 37

oxygen

Question 38

traits of methaemoglobin

Answer 38

Fe3+ 
Cannot bind oxygen
Usually formed during glycolysis
Can be inherited or acquired
RR 0.2-0.6%
Inherited with: cytochrome b5 reductase deficiency and Haemoglobin M

Question 39

Low levels of CO have major impact on

Answer 39

haemoglobin function

Question 40

Haemoglobinopathies

quantitative defect

Answer 40

Reduced synthesis of normal globin chains

Thalassaemias

Question 41

Haemoglobinopathies

qualitative defect

Answer 41

Structural variants
HbS
HbC
HbD
Hbe

Question 42

Thalassaemia describes conditions involving

Answer 42

globin chain imbalance