Protein V

Question 1

ferrohemoglobin

Answer 1

Fe+2, binds O2

Question 2

ferrihemoglobin

Answer 2

Fe+3, does not bind O2

Question 3

Fe+2

Answer 3

has proximal histidine on one side and binds O2 on other side

Question 4

proximal histidine

Answer 4

binds the iron in heme

Question 5

distal histidine

Answer 5

prevents heme groups from coming too close together –> prevents oxidation of iron; also reduces affinity of CO for heme

Question 6

pO2 in capillaries

Answer 6

about 20 torr

Question 7

when oxygen binds Fe _

Answer 7

it pulls it into the porphyrin plane, pulling proximal histidine into plane as well, causing it to reposition –> conformational change = quaternary structure

Question 8

tense (T) state

Answer 8

deoxygenated heme

Question 9

relaxed (R) state

Answer 9

oxygenated heme

Question 10

sequential model

Answer 10

each heme independently converts from R to T

Question 11

the higher the pO2 _

Answer 11

the more oxygen present in blood

Question 12

stabilization of T state

Answer 12

releases O2

Question 13

stabilization of R atate

Answer 13

binds O2 (high affinity)

Question 14

muscles actively working

Answer 14

when active, muscles release CO2 and H+ –> this stabilizes the T state, causing the unloading of oxygen for the muscles

Question 15

Bohr effect in lungs

Answer 15

high O2 promotes release of CO2 and H+

Question 16

pO2 curve when more H+ (same for CO2)

Answer 16

protons stabilize the T state –> shifts pO2 curve to the right (causes higher pO2 because oxygen is released into blood)

Question 17

formation of carbamates

Answer 17

stabilize T state

Question 18

pKa in deoxyhemoglobin

Answer 18

pKa raised in histidine and terminal NH2 groups

Question 19

2,3-BPG

Answer 19

2,3-BPG will only bind the T state –> no 2,3-BPG means R state –> so 2,3-BPG stabilizes T state; also it is synthesized during glycolysis

Question 20

hypoxia

Answer 20

induces production of 2,3-BPG (allows shift from R to T to unload more oxygen)

Question 21

2,3-BPG in RBCs

Answer 21

bonds hemoglobin and lowers its affinity for O2

Question 22

Haldane effect

Answer 22

deoxygenation of the blood leads to an increase in its ability to carry CO2

Question 23

fetal hemoglobin

Answer 23

alpha2gamma2; binds O2 with higher affinity because it binds BPG less tightly

Question 24

microcytic anemia

Answer 24

tissues and organs do not get enough oxygen due to either decreased RBCs or lack of hemoglobin

Question 25

most common cause of microcytic anemia

Answer 25

iron deficiency and thalassemia

Question 26

microcytic anemia symptoms

Answer 26

pale skin, weakness, irritability, shortness of breath, rapid HR, pica

Question 27

valine vs glutamate (sickle cell)

Answer 27

valine is non-polar and hydrophobic, causing increased hydrophobicity in hemoglobin