gas transport

Question 1

describe the structure of Hb monomers

Answer 1

ferrous Fe2+ at centre of ring connected to protein chain; covalently bonded at proximal histamine residue; 2a and one of 2B (HbA), d (HbA2), y chain (HbF - foetal)

Question 2

describe the process of conformational change at cooperative binding

Answer 2

as O2 binds, it allows easier binding of more O2 until not much greater capacity so less O2 bind

Question 3

explain the principle of allosteric regulation

Answer 3

tense - 0% saturated, O2 released, low affinity; relaxed - 100% saturated, high affinity

Question 4

describe methaemoglobin (MetHb)

Answer 4

Fe3+ which doesn’t bind O2; <1% of total Hb; exists in dynamic eqm with Hb Fe2+ so constant changes except at high volumes or in medication

Question 5

describe foetal Hb

Answer 5

y chains have greater affinity (left) than adults HbA to ‘extract’ O2 from mother’s blood in placenta

Question 6

describe myoglobin

Answer 6

in muscle much greater affinity (left) than adult HbA to ‘extract’ O2 from circulating blood and store it - high intentity low duration

Question 7

Hb saturation

Answer 7

75% saturated when return back to lungs

Question 8

what does methylene blue do

Answer 8

increases Hb from MetHb