Haemoglobin

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!

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

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.

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.

Haemoglobin: the Oxygen Carrier

  Haemoglobin is responsible for oxygen transport.

Haemoglobin contains Iron (II) ions: Fe 2+ :  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.

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 CO 2 H 2 CO 3 .

and H 2 O to bind together to form H + ions are formed, which then bond to haemoglobin to form HHb: Haemoglobinic acid. This bond then displaces the oxygen, which is released.

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.)

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.

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.

Ye Olde End

Mastermind, genius and director:

Charlie Wilkes

Helpful Person / Researcher: James Johnson Slacker: Roshan Tajapra.