Transport of O2

Question 1

Adaptations of Erythocytes (RBCs)

Answer 1

Biconcave shape => maximises surface area for gas exchange
Small +flexible to pass through through narrow capillaries
No nucleus => move room to carry respiratory gases
Packed with haemoglobin (HB)

Question 2

Haemoglobin

Answer 2

Protein making up 95% of mass of RBC + is means of transport of oxygen around the body

Made of 4 polypeptide chains each bonded to 1 haem group

Each haem group contain 1 O molecule so ecah HB carries 4 Os max

Question 3

Oxygen in the lungs diffuse into RBCs

Answer 3

O2 diffuses into blood plasma - down conc gradient to RBC - and binds to HB

Question 4

Oxygen in respiring tissues

Answer 4

Oxygen dissociates from oxyhaemoglobin and diffuses out of erythocytes to respiring cells

Question 5

Effect of O2 conc on diffusion

Answer 5

O binds to HB when O is at high conc + dissociates from HB at low conc

=> conc of gas in a mixture of gases can be qualified as partial pressure

Question 6

When oxygen dissociation curve shifts to left (e.g. fetal HB)

Answer 6

The <= the curve, the more readily the pigment associates with O2 but the less readily it dissociates

Question 7

When oxygen dissociation curves shifts to the right

Answer 7

The more => the curve the less readily the pigment asociates w/ O2 but the less readily it dissociates