4.5 Flashcards

(7 cards)

1
Q

structure of haemoglobin in relation to its role in transport of resp gases

A

haemoglobin = large globular protein - 4 ham grps - 4 peptide chains
- each harm grp can bind to one o2 molecule <-> oxyhemoglobin
- 1st o2 is difficult to bind to haem - but this then alters shape of molecule so easier for next o2 to bind - also means that also gets progressively harder for o2 to leave/dissociate harm grp

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2
Q

why is o2 always diffusing in and binding to RBC

A

in lungs = high conc of O2, diffuses into RBC - loads + binds to haem grp - but free O2 conc in cytoplasm of RBC therefore always a conc gradient - so more o2 diffusing in

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3
Q

what is the Bohr effect

A

changes in o2 dissociation curve that result as the CO2 level changes

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4
Q

how does affinity for o2 change in dif co2 cones

A
  • high co2 levels = lower affinity for o2 so easily more readily lost
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5
Q

how is co2 transported in blood

A
  • in respiring tissue - higher conc of CO2 - diffuses into RBC + combines w water
  • Co2 + H20 <- (this is catalysed by carbonic anhydrase)-> H2Co3 (carbonic acid) <-> H+ + HCO3-
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6
Q

Understand the similarities and differences between the structures and functions
of haemoglobin and myoglobin.

A
  • myo = 1 harm grp - acts as O2 store as only releases o2 in v low conc - high CO2 conc
  • higher affinity than haem
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7
Q

Understand the significance of the oxygen affinity of fetal haemoglobin as
compared to adult haemoglobin.

A
  • higher affinity
  • so that feral blood can remove o2 from mum’s blood - also countercurrent exchange system to maximise o2 transfer
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