Chapter 9

Question 1

Myoglobin and Hemoglobin bind

oxygen to heme prosthetic groups T or F?

Answer 1

True

Question 2

Heme Ring….

Answer 2

protoporphyrin made up of four pyrole rings linked by methane bridges
contains a central iron ion in the ferrous form (Fe2+) with four coordinate bonds to nitrogen atoms

Question 3

Iron

Answer 3

forms fifth coordinate bond with histidine, proximal histidine
forms a sixth coordinate bond with oxygen
responsible for the color change in blood

Question 4

Deoxygenated blood

Answer 4

purplish

Question 5

Oxygen rich blood

Answer 5

Red

Question 6

Fe3+ state blood

Answer 6

brownish red

Question 7

Distal Histidine

Answer 7

Hydrogen binds with O2
prevents irreversible oxidation
of Fe2+ to Fe3+, which cannot bind O2
reduces heme binding affinity for CO

Question 8

Myoglobin

Answer 8

Myoglobin (Mb) is a single polypeptide chain consisting of a-helicies.

Question 9

Oxygen Binding Curve for Myoglobin is Hyperbolic T or F?

Answer 9

True

Question 10

The Bohr Effect

Answer 10

CO2 and H+ Released by Respiration Enhance O2 Release by Hb

Question 11

Hb demonstrates the cooperative

effect

Answer 11

high O2 affinity at high pO2
low O2 affinity at low pO2
O2 is a homotropic allosteric activator of Hb

Question 12

Hemoglobin (Hb) is a tetrameric protein (or a dimer of dimers)

Answer 12

2 a and 2 b subunits (or α1β1 and α2β2)

each subunit contains a heme ring

Question 13

T state

Answer 13

Deoxyhemoglobin
O2 binding triggers T to R
Low Affinity

Question 14

R state

Answer 14

Oxyhemoblogin
O2 binding stabilizes R
High Affinity

Question 15

Sickle-Cell Hemoglobin (HbS)

Answer 15

HbS differs from HbA by a single amino acid substitution, Glu → Val on the b subunits.