haemoglobin

Question 1

what does haemoglobin do?

Answer 1

● loads O2 (at lungs to form oxyhaemoglobin)

● oxyhaemoglobin carries O2 to respiring cells

● unloads O2 at respiring cells (reforms haemoglobin)

● quaternary protein with associated iron (Fe2+) containing haem groups

● protein found in rbc

Question 2

explain lungs / alveoli

Answer 2

● PALS

● high ppO2 (high conc of oxygen)

● high affinity (more likely to be loading O2)

● loading

● saturated (more O2 molecules loaded)

Question 3

explain respiring cells

Answer 3

● PALS

● low ppO2 (low conc of oxygen)

● low affinity for O2

● unloading

● less saturated

Question 4

what is the shape of the ODC?

Answer 4

sigmoidal curve

Question 5

what is cooperative bonding?

Answer 5

● loading of first oxygen changes tertiary structure of haemoglobin

● exposes second haeme group binding site

● increases affinity of haemoglobin - second O2

● loads more readily

Question 6

explain haemoglobin affinity for O2 at different partial pressures

Answer 6

● at same ppO2 haem = more saturated
higher affinity for O2 at any ppO2

● e.g. lugworm

● in low ppO2 environment

● needs to have high affinity

● left shifted

● at same ppO2 haem = less saturated
lower affinity for oxygen at any partial pressure

● e.g. hummingbird

● lots of muscular contractions

● so needs lots of ATP

● from aerobic respiration

● e.g. field mouse

● high metabolic rate

● due to high SA:V ratio

● meaning heat lost at a higher rate