Hemoglobin & Porphyrins

Question 1

Porphyrins are synthesized in the…

Answer 1

Liver and bone marrow.

Question 2

What is the most common way to differentiate between porphyrins and porphyrinogens?

Answer 2

Porphyrins fluoresce red at 400 nm, while porphyrinogens do not.

Question 3

What determines solubility in porphyrin and porphyrinogen?

Answer 3

Number of carboxyl groups.

Question 4

Heme synthesis takes place in…

Answer 4

Nucleated red cells and early reticulocytes.

Question 5

What enzyme is used for the following reaction?

Answer 5

ALA Synthase.

Question 6

What enzyme is used for the following reaction?

Answer 6

ALA Dehydratase.

Question 7

Describe a porphyrin ring.

Answer 7

4 pyrrole rings connected by methene bridges (double bond).

Question 8

In heme synthesis, a deficiency in ALA dehydratase will cause what condition?

Answer 8

Plumboporphyria (PP).

Question 9

In heme synthesis, a deficiency in PBG deaminase will cause what condition?

Answer 9

Acute intermittent porphyria (AIP).

Question 10

In heme synthesis, a deficiency in Uroporphyrinogen III synthase will cause what condition?

Answer 10

Congenital Erythropoietic Porphyria (CEP).

Question 11

In heme synthesis, a deficiency in Uroporphyrinogen decarbodylase will cause what condition?

Answer 11

Porphyria cutanea tarda (PCT); Hepatoerythropoietic porphyria (HEP).

Question 12

What are the three types of hemoglobin?

Answer 12

Hemoglobin A, A2, and F.

Question 13

ALA synthase and ALA dehydrase can be inhibited by ___.

Answer 13

Heme.

Question 14

Ferrochelatase can be inhibited by ___ and ___.

Answer 14

heme; protoporphyrin IX.

Question 15

Hemoglobin has a high ___ which allows it to readily pick up oxygen.

Answer 15

affinity.

Question 16

What is the function of 2,3-bisphosphoglycerate (BPG) in the movement of oxygen and CO2?

Answer 16

Prevents oxygen from reattaching to heme groups.

Question 17

Describe the oxygen dissociation curve (ODC).

Answer 17

Predicts the amount of saturated hemoglobin in regards to the amount of oxygen that is present.

Question 18

What two factors affect hemoglobin’s affinity for oxygen?

Answer 18

pH and body temperature.

Question 19

How will the following situation affect hemoglobin’s affinity to retain oxygen:
↑pH; ↑ affinity; ↓ temp; ↓DPG

Answer 19

Hemoglobin will retain oxygen.

Question 20

How will the following situation affect hemoglobin’s affinity to retain oxygen:
↓pH; ↑temp; ↑DPG; ↓affinity

Answer 20

hemoglobin will readily release oxygen.

Question 21

Lead poisoning causes an inhibition of which enzymes?

Answer 21

ALA dehydrase, coproporphyrinogen oxidase, and ferrochelatase.

Question 22

Lead poisoning causes an elevated excretion of which enzymes?

Answer 22

ALA, urine coproporphyrin III, and erythrocyte protoporphyrin IX.

Question 23

In neuropathy in lead poisoning increased ___ competes for binding sites for gamma amino butyric (neurotransmitter).

Answer 23

ALA.

Question 24

Hoesch test is used to test for what?

Answer 24

Porphobilinogen.

Question 25

In the Hoesch test, PBG forms what color?

Answer 25

Red.

Question 26

What is the reagent used in the Watson-Schwartz test?

Answer 26

p-dimethyl aminobenzaldehyde.

Question 27

PBG forms a ___ pigment in the Watson-Schwartz test.

Answer 27

Pink.

Question 28

The Watson-Schwartz test is used to detect ___ or false ___ which would produce the red color.

Answer 28

porphobilinogen; urobilinogen.

Question 29

Methemoglobin and Carboxy hemoglobin is measured by what instrument?

Answer 29

Cooximeter.

Question 30

Describe Methemoglobin.

Answer 30

Ferric forms a +3 form; doesn’t carry oxygen.

Question 31

Describe Carboxy Hemoglobin.

Answer 31

Caries CO rather than oxygen.

Question 32

Describe Sulfhemoglobin.

Answer 32

Doesn’t carry oxygen.

Question 33

RBCs breakdown into what three components?

Answer 33

Iron, Globin, and Heme oxidase.