Lecture 5 HB

Question 1

TheT –> R transition changes hemoglobin Affinity for O2 how

Answer 1

in the T state no O2 is bound but as soon as one is bound there is a increase in affinity for O2

Question 2

What effector stabilizes the T or R states

Answer 2

Allosteric Effectors

Question 3

What are the negative allosteric effectors and how to they stable the T-state

Answer 3

BPG, CO2 and H+

Shift binding curve to the right

Question 4

What are the positive allosteric effectors?

Answer 4

CO stabilizes the R state(Keeps O2 bound) and shifts curve to the Left

Question 5

Compare and contrast Hb and Mb In terms of

-Physiological roles

Answer 5

Hb is used for O2 transportation and
Mb is used for O2 storage in Tissues

Question 6

Compare and contrast Hb and Mb In terms of

-Structure

Answer 6

Myoglobin is a single polypeptide chain w/ a heme group

Hemoglobin is a tetramer of 2 AB subunits w/ heme group

Monomers hemoglobin are structurally similar to myoglobin

Question 7

Compare and contrast Hb and Mb In terms of

-O2 Affinity

Answer 7

Myoglobin saturation curve is hyperbolic- O2 binds tightly and only releases when needed(Anoxic conditions)

Hemoglobin saturation curve is sigmoidal binds to O2 at a lower affinity.

Lungs: O2 binds to hemoglobin
Tissues: O2 Releases from hemoglobin
Tissues: Co2 Binds to Hemoglobin
Lungs: CO2 released from Hemoglobin

Question 8

Describe the structural basis from cooperative(allosteric) binding of O2 by hemoglobin but not myoglobin

Answer 8

When O2 binds it pulls the monomer more planner which allows for more O2 to bind.

Question 9

Understand the saturation curves for hemoglobin and my glib and how it changes with allosteric effectors.