Haemoglobin and Heamoglobinisation

Question 1

What is the molecular mass of H?

Answer 1

64-65.5 kDA

Question 2

Why is both haem and globin essential?

Answer 2

Haem is important for O2 transport, while globin serves to protect haem from oxidation; renders the molecule soluble and permits variation in O2 affinity.

Question 3

What are the three phases of haemoglobinisation?

Answer 3

Embryonic, foetal and adult.

Question 4

What makes the haemoglobin different during the different phases?

Answer 4

The globin chains.

Question 5

Which 2 chromosomes are responsible for globin syntheses?

Answer 5

11 and 16

Question 6

What four things incl a globin chain does chromosome 11 code for?

Answer 6

Beta globin, ɛ , 𝝲, ẟ

epsilon, gamma, delta

Question 7

What 2 things does chromosome 16 code for?

Answer 7

Alpha globin, 𝝵 (zeta)

Question 8

How many different types of h are there?

Answer 8

7 - A, A2, F, G1, G2, P1, P2

Question 9

Which globin chains are synthesised by the 5th week of gestation in primitive erythroblasts?

Answer 9

ZE - zeta and epsilon, with the production of G1, G2, P1 and P2

Question 10

Which globin chains are synthesised from week 6 on?

Answer 10

ABG - alpha, beta and gamma.

Question 11

Which H is in the embryo is essential for life and why?

Answer 11

G2

Inability to produce H A which is incompatible with life.

Question 12

Where is H synthesised in the 10-12 weeks of gestation?

Answer 12

In the liver and the spleen with the production of F and later HA

Question 13

What proportion of HA is in a normal healthy adult?

Answer 13

~97%

Question 14

What proportion of HA 2 is in a normal healthy adult?

Answer 14

~2.0 - 3.3%

Question 15

What proportion of H F is in a normal healthy adult?

Answer 15

~0.2 - 1%

Question 16

How much iron per mg/kg is in the male body?

Answer 16

50mg/kg

Question 17

How much iron per mg/kg is in the female body?

Answer 17

35mg/kg

Question 18

How is the majority of the body’s iron stored/which form?

Answer 18

65% - Haemoglobin

30% - Ferritin and its insoluble Hemosiderin in macrophages, marrow, liver, spleen

Question 19

How is iron found in the cells?

Answer 19

In cytochrome enzymes in cells.

Question 20

What is iron bound to ?

Answer 20

The iron transport protein in the blood; transferrin.

Question 21

How much iron is absorbed based on a western diet of 10-15mg of iron daily?

Answer 21

5-105 is absorbed.

Question 22

What are the two forms of haem ?

Answer 22

Haem and Non-haem forms in ferrous ++ and ferric +++ states.

Question 23

Which is the more easily absorbed type of iron in food?

Answer 23

The ferrous , it is absorbed more rapidly than the ferric form.

Question 24

Which enzyme facilitates the release of haem iron in the gut?

Answer 24

Haemoxygenase 1

Question 25

Which form is non-haem iron usually found?

Answer 25

In the Ferric +++ form

Question 26

Which enzymes facilitates the conversion of ferric iron to ferrous iron for easier absorption?

Answer 26

Ferroreductase

Question 27

What does the haem molecule consist of?

Answer 27

• Protoporphyrin ring
• iron molecule in centre
• 4 pyrrole groups united by methan bridges

Question 28

What is free iron absorbed by?

Answer 28

Enterocytes in the gut, via a specific cell membrane called the Dimetal trasnporter-1 (DMT 1)

Question 29

What does ferroportin do and what manages it?

Answer 29

Ferroportin is on the surface of enterocytes and has a role in the export of iron into circulation.
Hepcidin

Question 30

What does hepcidin do?

Answer 30

It manages the level of ferroportin, increase or decrease - role in the amount of iron being transferred into circulatory system.

Question 31

Which iron transport protein transports iron over the brush border in the gut?

Answer 31

Transferrin molecule.

Question 32

What are the names of the iron stores in the tissue macrophages?

Answer 32

Ferritin and hemosidirin.

Question 33

Where is iron primarily absorbed?

Answer 33

In the duodenum and the upper jejunum where acidic conditions help the absorption.

Question 34

Which reducing substances aid iron absorption?

Answer 34

HCL and Ascorbic acid.

Question 35

What are the 3 main causes for losses of body iron?

Answer 35

• menstruation
• GI bleeds
• epithelial cells from skin, gut or urinary tract

Question 36

What are the names of the three IRON CARRIER PROTEINS which bring free iron to the liver for synthesising?

Answer 36

Albumin
Lactoferrin
Transferrin ** n.b

Question 37

Why is transferrin (76-80kDA) the most important iron carrier?

Answer 37

It can carry 2 atoms of ferric iron.

Transferrin is then reutilised to pick up more free iron in the body.