Lecture 7

Question 1

what is the major hemoglobin in humans?

Answer 1

HBA

Question 2

hemoglobin is composed of what?

Answer 2

2 beta chains, 2 alpha chains

Question 3

what oxidation state is Fe in within hemoglobin?

Answer 3

2+

Question 4

how many bonds does Fe make while within hemoglobin and to what?

Answer 4

6 total.. 4 to porphyrin nitrogens, 1 above, 1 below.

Question 5

what are the three differences between hemoglobin and myoglobin?

Answer 5

1 - RBC vs Muscle
2 - transports vs stores
3 - tetramer vs monomer

Question 6

describe the bonds of deoxygenated hemoglobin and oxygenated hb.

Answer 6

1) - strong hydrophobic bonds between alpha and beta chains form 2 dimer pairs
- weak ionic and hydrogen bonds between dimer pair 1 and
2) some ionic and hydrogen bonds between dimer pairs are broken

Question 7

which conformation of hemoglobin has the higher affinity for oxygen?

Answer 7

Relaxed

Question 8

what causes hemoglobin to decrease affinity for oxygen (release o2)?

Answer 8

• think from the perspective of muscles. How will hemoglobin know it is near muscles that need oxygen?
  1) increased temperature due to muscle activity.
  2) decreased pH due to lactic acid and CO2 byproducts
  3) increased CO2 cellular waste
  4) increased BPG

Question 9

what causes hemoglobin to increase affinity for oxygen (obtain o2)?

Answer 9

• think from the perspective of lungs. How will hb know it is in the lungs where it needs to collect oxygen?
  1) decreased temperature due to atmospheric air.
  2) increased pH due to the quick removal of CO2 (a lewis acid).
  3) decreased BPG

Question 10

what happens with the removal of 2,3 - BPG?

Answer 10

the oxygen dissociation curve loses its sigmoid shape, becomes rectangle

Question 11

what is the haldane effect?

Answer 11

the binding of oxygen causes release of CO2 from hemoglobin and decreases its affinity for CO2.

Question 12

what happens when hemoglobin is exposed to carbon monoxide?

Answer 12

• hemoglobin has 220 times more affinity for CO than for O

- hemoglobin cannot release o2 to the tissues