Hemoglobin and Myoglobin

Question 1

What group is responsible for the oxygen binding capacity of hemoglobin?

Answer 1

Heme group

Question 2

What surrounds heme and protects the ferrous form from getting oxidized?

Answer 2

Globin

Question 3

If Fe2+ is oxidized what does it become?

Answer 3

Methomoglobin

Question 4

What facilitates oxygen storage in the muscle?

Answer 4

Myoglobin

Question 5

When looking at a graph what kind of curve will Myoglobin have?

Answer 5

Hyperbolic

Question 6

How many molecules of oxygens can hemoglobin bind to?

Answer 6

4 molecules of oxygen

Question 7

What enzyme works together with Hemoglobin to remove acidity from the tissues?

Answer 7

Carbonic anhydrase

Question 8

When looking at a graph in what type of fashion will hemoglobin plot?

Answer 8

sigmoidal

Question 9

A change in confirmation of T to R will increase what?

Answer 9

O2 affinity

Question 10

What does it mean when one says Oxygen binding is cooperative?

Answer 10

It means when Alpha 1 subunit is oxygen bound each subsequent oxygen binds with higher affinity that the previous. Similarly When one oxygen dissociates the other three will dissociate faster

Question 11

At which state does 2,3-BPG like to bind?

Answer 11

Tort state (deoxyhemoglobin)

Question 12

Lower pH favors T state which will cause what to Hemoglobin?

Answer 12

To release its Oxygen

Question 13

The release of what reinforces the Bohr effect?

Answer 13

CO2 because it lowers the pH

Question 14

When Iron becomes oxidized what condition is that called?

Answer 14

Methemoglobinemia

Question 15

Methemoglobinemia may result from 5 things. What are they?

Answer 15

1) Poisoning with oxidizing agents
2) Oveproduction of oxidants by enzymes
3) Failure of a cell to make glutathione (reduces oxidants)
4) Histidine of hemoglobin being replaced by tyrosine
5) methemoglobin reductase deficiency

Question 16

In the presence of CO (carbon monoxide) what does it do?

Answer 16

reversibly binds to Hemoglobin, which inhibits the release of oxygen from 2-4 heme units.

Question 17

Carbon monoxide is an example of what kind of effector?

Answer 17

Positive allosteric

Question 18

Carbon Dioxide is and example of what kind of effector?

Answer 18

Negative allosteric ( release of oxygen)

Question 19

When a patient has been expose to sublethal levels or Carbon monoxide he is place in a hyperbaric chamber. Why is this effective?

Answer 19

Being put in a high pressure chamber directs CO to bind at an angle instead of linearly so it weakens its affinity

Question 20

In higher altitude BPG favors which State and why?

Answer 20

BPG favors the Tort state because since higher altitude has less oxygen for the tissues it forces Hb to release to oxygen to generate more energy for the tissues.

Question 21

On a graph BPG will move to what side?

Answer 21

Right

Question 22

Once hemoglobin is stripped of BPG it acts similar to what and why

Answer 22

SIMILar to myoglobin which has little propensity to release oxygen

Question 23

Describe why Fetal hemoglobin cannot bind to 2,3BPG

Answer 23

Fetal Hb has replaced its His to Ser (which is less positive) so fetal Hb has a lower binding affinity to 2,3BPG compared to adults.

Question 24

Where would you find higher oxygen saturation in a pregnant patient ?

Answer 24

Fetus

Question 25

Fetal hemoglobin binds oxygen with greater affinity than adult hemoglobin because the fetus has lower affinity to what?

Answer 25

2,3-BPG ( remember the gamma chains of fetal hemoglobin each have a histidine residue replaced by a serine residue which cannot form salt bonds)

Question 26

The tort state is stabilized by what kind of bonds?

Answer 26

Salt bonds

Question 27

Majority of the carbon dioxide that is formed during metabolism is transported to the lungs in the blood by what ion?

Answer 27

bicarbonate ion

Question 28

When does myoglobin have a higher affinity for Oxygen when compared to the affinity of hemoglobin?

Answer 28

at lower partial pressures