oxygen carriage

Question 1

what does oxygen and haemoglobin produce

Answer 1

oxyhaemoglobin -402+hb - hb(o2)4

Question 2

what is cooperative binding?

Answer 2

binding of one 02 molecule changes shape of haemoglobin making it easier for another to bind.

Question 3

what is affinity

Answer 3

how well haemoglobin binds to oxygen.

Question 4

what is shown on an oxygen dissociation curve

Answer 4

the conc of o2 /partial pressure with the conc of oxygen carried by red blood cells /percentage saturation .

Question 5

what happens at high partial pressures of oxygen

Answer 5

haemoglobin is being loaded with oxygen.
-carries max amount of o2 molecules.
-haemoglobin is saturated.

Question 6

what happens at low partial pressures of oxygen-

Answer 6

haemoglobin is being unloaded.
-haemoglobin dissociates and releases oxygen.

Question 7

why is the curve s shaped.

Answer 7

when haemoglobin releases and 02 molecule it binds/releases a 2nd more quickly. haemoglobin is more efficient at unloading o2 over a range of partial pressures of oxygen.

Question 8

how are llamas adapted to a low partial pressure environment.

Answer 8

haemoglobin has a higher affinity for all partial pressures and oxygen is loaded in lungs at low partial pressures.

Question 9

how are lugworms adapted o a low partial pressure

Answer 9

low metabolic rate-little o2 requirement.
-its haemoglobin loads over a range of partial pressures and only unloads at very low pp.

Question 10

how is foetal haemoglobin adapted to its environment.

Answer 10

has a higher affinity for o2 than adult haemoglobin at same partial pressure. at all partial pressures, oxygen will transfer from maternal to foetus. foetal haemoglobin will become saturated at lower partial pressures than adult haemoglobin. The higher affinity allows it to take oxygen from maternal haemoglobin across the placenta.

Question 11

what is myoglobin

Answer 11

an oxygen carrying molecule found in muscles and only releases o2 when there is very little oxygen In the muscle.
has a a high affinity for oxygen at very low partial pressures of oxygen so acts as a oxygen store.

Question 12

what is the bohr effect

Answer 12

as the conc of co2 increases, haemoglobin releases o2 more readily so at all partial pressures of oxygen the haemoglobin is less saturated. the bohr shift moves to right so haemoglobin is more efficient at unloading 02 and delivers oxygen to respiring cells.

Question 13

what are the 3 ways co2 is transported.

Answer 13

1. carried in plasma as hydrogen carbonate ions (HCO3-)(85%)
   2.bound to haemoglobin as carbamino-heamoglobin (10%)
   3.dissolved in plasma (5%)

Question 14

how is c02 made into hydrogen carbonate ions

Answer 14

in plasma -slow reaction-no enzyme use
co2 + H20 =carbonic acid
dis dissociates to form a proton and a hydrogen carbonate ion.
in red blood cell the same reaction occurs quickly with the enzyme carbonic anhydrase.

Question 15

what happens to the proton

Answer 15

combines with oxyhaemoglobin to form haemoglobonic acid. this increases the rate of oxygen release. The removal of H+ ions prevents lowering of PH in blood.

Question 16

H+ ions and the bohr shift

Answer 16

the more c02 present the more H+ ions produced so more o2 is released from haemoglobin. the higher the partial pressure of co2 the lower the affinity for oxygen.

Question 17

what happens with the hydrogen carbonate ions

Answer 17

diffuse out of red blood cells down a conc gradient into plasma creating a charge imbalance.

Question 18

how is electrical neutrality maintained.

Answer 18

chloride ions diffuse into red blood cell-chloride shift.

Question 19

how is oxygen released from haemoglobin

Answer 19

when concentration of co2 accumulates and forms carbonic acid the ph becomes more acidic which releases oxygen from oxyhaemoglobin.