Haemoglobin

1. Haemoglobin

2. Basic Knowledge: • Haemoglobin is an iron protein - compound in red blood cells that transports oxygen, carbon dioxide, and nitric oxide. • It carries oxygen to body cells. After releasing oxygen to the body tissues, haemoglobin picks up carbon dioxide and transports it to the lungs. • Haemoglobin is contained entirely in the red blood cells. • A lack of haemoglobin caused by iron deficiency leads to anaemia . • Haemoglobin containing iron is the reason for the red colour of blood: • Iron has a variable oxidation state, where it can form more than one stable ion with its outermost electron in the d-orbital: it is a transition metal. • This comes in handy for oxygen transport!

3. Haemoglobin: the Protein • Human haemoglobin consists of four chains: • Two identical Alpha chains • And two identical Beta chains. • Each of these chains is bound to a non protein group called haem. This results in… Haemoglobin

4. Haemoglobin: the Protein Structure: • Haemoglobin has a primary, secondary, tertiary and quaternary structure: • Secondary: alpha helix. • Tertiary: helical and non - helical units fold to form a compact unit. • Quaternary: when all four separate chains group to form the full protein. • The quaternary structure is what makes each protein so very individual.

5. Haemoglobin’s Structure: • The diagram to the right is how the four protein chains pack together to form human haemoglobin: • Green and yellow: alpha. • Blue and orange: beta.

6. Haemoglobin: the Oxygen Carrier • Haemoglobin is responsible for oxygen transport. • Haemoglobin contains Iron (II) ions: Fe2+: • Iron has a variable oxidation state, so oxygen can bind to it: this is where blood changes colour! • Because each haemoglobin molecule has four haem groups, it can bond to four oxygen molecules.

7. How Does It Do It? • Oxygen binds easily to haemoglobin. • When it is needed (for example in muscles), oxygen is released. • There is an enzyme in red blood cells’ cytoplasm called carbonic anhydrase. • This prompts CO2 and H2O to bind together to form H2CO3. • H+ ions are formed, which then bond to haemoglobin to form HHb: Haemoglobinic acid. • This bond then displaces the oxygen, which is released.

8. Haemoglobin Variations: • Myoglobin. • Myoglobin is the muscle’s version of haemoglobin. • It has a much deeper red colour. • It can only accept two oxygen molecules. • It only releases oxygen in times of EXTREME need. (Like exercise.)

9. Foetal Haemoglobin • Foetuses do not acquire their oxygen through their lungs. • Oxygen is diffused across the placenta. • Foetal Haemoglobin has a higher affinity for oxygen than maternal haemoglobin. • This allows it to “attract” oxygen from the mother to use for aerobic respiration.

10. Anaemia: • This is when one of the four chains in haemoglobin contains one different amino acid than normal. • This results in the red blood cell forming a sickle shape: thus it is called: • Sickle Cell Anaemia. • Normally caused by a lack of iron, but some types are genetic.

11. Ye Olde End Mastermind, genius and director: Charlie Wilkes Helpful Person / Researcher: James Johnson Slacker: Roshan Tajapra.