Heamoglobin

Question 1

what type of protein is heamoglobin and why?

Answer 1

qauternary -has 4 polypetide chain

Question 2

give the equation for oxygen loading

Answer 2

Hb+4O2->HbO8
haemoglobin +oxygen -> oxyheamoglobin

Question 3

give the equation for oxygen unloading

Answer 3

HbO8->4O2+Hb
oxyhaemoglobin ->oxygen +haemoglobin

Question 4

where is oxygen loaded ?

Answer 4

lungs

Question 5

where is oxygen unloaded

Answer 5

respiring cells

Question 6

what is affinity?

Answer 6

ability of a molecule to bind to something

Question 7

what is the symbol for partial pressure of oxygen?

Answer 7

PO2

Question 8

what does higher PO2 mean?

Answer 8

greater concentration of dissolved oxygen in cells

Question 9

as PO2 increases…

Answer 9

haemoglobin affinity for oxygen also increases

Question 10

what ‘letter’ shape is a haemoglobin dissociation curve?why does this matter?

Answer 10

‘S’ shape , not linear

Question 11

what is on the Y and X axis of the curve ?

Answer 11

X axis is partial pressure of O2 /KPa

Y axis is % saturation of haemoglobin with oxygen

Question 12

what happens at the start of the graph ?

Answer 12

when PO2 is low haemoglobin has a low affinity for O2 ,so a low saturation if O2 .

Question 13

what happens at the top of the graph ?

Answer 13

When PO2 is high in the lungs ,haemoglobin has a a high affinity for O2 so it has a high saturation of O2

Question 14

why is the haemoglobin dissociation curve s shaped?

Answer 14

saturation affects affinity .When haemoglobin binds with the first O2 molecule ,3d shape of haemoglobin changes , The altered shape means it is easier for 2nd O2 molecule to bind .As haemoglobin becomes more saturated it becomes harder for O2 to bind .

Question 15

what is PCO2?

Answer 15

partial pressure of CO2

Question 16

what effect does PCO2 have on oxygen unloading #?

Answer 16

Hb gives up O2 more readily at a higher PCO2 .More O2 to cells during same affinity .CO2 makes blood more acidic which changes the hap of the protein haemoglobin

Question 17

describe the steps of the Bohr effect?

Answer 17

1.cells respire and produce more CO2 which raises PCO2
2.decrease in Ph
3.increased rate of O2 unloading
4.dissosiation curve shifts tot the right
5.Hb affinity is decreased so more O2 relesead

Question 18

what heamoglobin type do organisms with a low oxygen avalibility have and why?

Answer 18

higher affinity for oxygen then human Hb
not as much oxygen avalible so heamoglobin is very good at loading and unloadinh

Question 19

what type fo oxygen dissosiation curve do organisms with a low oxygen avalibiltiy have ?

Answer 19

to left

Question 20

what type of oxygen dissosiation curve do organisms with a high activity level have and why ?

Answer 20

Hb has lower affinity
Hb unload easier , avalible to use
oxygen to right due to high respiration level

Question 21

what type of oxygen dissociation curve do organisms with a high SA:V have and why ?

Answer 21

lose heat quick so high metabolism to keep heat working well
high oxygen demand
Hb has a lower affinity for O2 as Hb needs to easily unload O2
move to right