Hemoglobin Structure and Function

Question 1

Ferrous iron is _____.

Answer 1

Fe2+

Question 2

Ferric iron (Fe3+) cannot bind _____.

Answer 2

oxygen

Question 3

Ferric iron in methemoglobin is reduced by ______.

Answer 3

cytochrome b5 reductase

Question 4

What is P50?

Answer 4

P50 is the partial pressure value at which hemoglobin is half saturated.

Question 5

Acidic solutions ____ the oxygen affinity of hemoglobin.

Answer 5

decrease

Question 6

Increases in CO2 _____ the oxygen affinity of hemoglobin.

Answer 6

decrease

Question 7

Temperature is _________ to the oxygen affinity of hemoglobin.

Answer 7

inversely proportional

Question 8

2,3-BPG ______ the oxygen affinity of hemoglobin.

Answer 8

decreases

Question 9

Alpha chains replace ______ chains.

Answer 9

zeta

Question 10

Gamma chains replace ______ chains.

Answer 10

epsilon

Question 11

Hemoglobin A2 functions like hemoglobin A. It is composed of ______.

Answer 11

alpha2/delta2

Question 12

Heinz body anemia results from _____.

Answer 12

unstable hemoglobins precipitating in RBCs

Question 13

Those with unstable hemoglobin disorders need ______.

Answer 13

folic acid (blood transfusions are usually unnecessary)

Question 14

Disorders in which hemoglobin’s oxygen affinity is enhanced result in ____ RBC counts.

Answer 14

increased (because the Hgb doesn’t release O2 and the kidneys think the body is hypoxic)

Question 15

Methemoglobinemia can be caused by _______, among other things.

Answer 15

cytochrome-b5 reductase deficiency, contaminated well water (with nitrates), and drugs such as benzocaine, sulfa, dapsone, and phenacetin

Question 16

Methemoglobinemia can be treated with ______ (if metHgb levels are greater than 40%).

Answer 16

methylene blue

Question 17

In addition to competitively binding at the O2 sites, CO also ____ shifts the oxygen binding curve, thus making it harder for hemoglobin to release O2.

Answer 17

left

Question 18

High-affinity hemoglobins (such as Chesapeake hemoglobin) lead to ______.

Answer 18

erythrocytosis

Question 19

Chronic methemoglobinemia requires ______ for treatment, but acute methemoglobinemia levels greater than _____ require ______.

Answer 19

nothing; 30%; methylene blue

Question 20

Carboxyhemoglobin will give a falsely _____ pulse-ox reading.

Answer 20

high

Question 21

Hemoglobin Koln is a mutation in the ____ chain that results in ______ affinity hemoglobin.

Answer 21

beta; increased

Question 22

Hemoglobin Poole is a mutation in the _____ chain that results in _________ that resolves after birth.

Answer 22

gamma; infantile hemolytic anemia

Question 23

List three causes of cyanosis.

Answer 23

Excess deoxyhemoglobinemia (many causes)
Excess methemoglobinemia
Sulfhemoglobinemia

Question 24

Methemoglobin is _____ shifted.

Answer 24

left

Question 25

Hemoglobin M is __________.

Answer 25

methemoglobin

Question 26

CO poisoning _____ shifts the hemoglobin binding curve.

Answer 26

left