Blood

Question 1

Haemoglobin

Answer 1

Globular protein, quaternary structure
Made of alpha and beta chain
Prosthetic haem group with Fe ions
Each haem carries 1 O2 molecule
4 Haemoglobin carries 4 O2

Question 2

Loading, unloading of oxygen

Answer 2

Hb with high affinity takes up oxygen in the alveoli more easily, unloads less easily at tissues
Vice versa

Question 3

Affinity of oxygen

Answer 3

High O2 conc, low CO2 conc, high affinity, O2 load

Low O2 conc, high CO2 conc, low affinity, O2 unload

Question 4

Types of Hb

Answer 4

Different species have different oxygen affinities

Slightly different amino acid sequence

Question 5

Oxygen percentage saturation

Answer 5

Highest saturation, high affinity, most loading, least unloading
Lowest saturation, low affinity, least loading, most unloading

Question 6

Bohr effect

Answer 6

Increased CO2 in bloodstream, move curve to the right

Lower affinity

Question 7

Exercise on the blood saturation curve

Answer 7

O2 moves from high to low partial pressure
Less loading, more unloading
More CO2 in blood

Question 8

RBC equations

Answer 8

CO2 (plasma) =>(diffuse) CO2 + H2O
CO2 + H2O <=> (carbonic anhydrase cat) H2CO3
H2CO3 <=> (dissociation) H+ + HCO3-
H+ + HCO3- => (diffusion) HCO3- (plasma)
Cl- (plasma, diffuse in to balance movement of anions, chloride shift)
H+ + HbO8 => HHb + 4O2
4O2 (diffuses out into plasma)

Question 9

Oxygen dissociation curve

Answer 9

Sigmoid shape
Cooperative binding, after 1st O2 molecule loads (difficult)
2nd and 3rd load more easily
4th loads less easily statistically

Question 10

How does oxygen get loaded and unloaded

Answer 10

High partial pressure of O2 in alveoli than caps
O2 diffuses into capillary, binds to Hb in RBC at higher PO2, higher affinity, low PCO2
TIssue, low partial pressure, O2 used in resp, lower O2 affinity
High PCO2, Bohr effect to the right, Hb changes shape, unload O2 at lower partial pressure

Question 11

Factors affecting oxygen affinity curves

Answer 11

Temperature
CO2
pH
Altitude
Metabolism
Function

Question 12

Llamas and mice

Oxygen affinity curves

Answer 12

Llama
High altitude, low PO2
Hb, increased O2 affinity
Loaded more easily
Curve to the left

Mice,
High metabolism, lots of respiration
Loaded less easily
Hb O2 affinity, low
Curve to the right

Question 13

Myoglobin and foetal Hb

Oxygen affinity curve

Answer 13

Myoglobin
Used to store O2 in muscles
Only offloads O2 at low PO2
Emergency O2 provision
To the left

Foetal Hb,
High affinity for O2
Allows foetal Hb to load O2 from adult Hb at placenta
to the right