Blood 1

Question 1

In the Fenton reaction, hydrogen peroxide (H2O2) is transformed to the highly reactive hydroxyl radical if it reacts with:

a. Calcium
b. Chloride
c. Iron
d. Oxygen

Answer 1

C. Iron

The Fenton reaction:
Free iron is extremely toxic as it can catalyze the formation of hydroxyl radical (OH·) from hydrogen peroxide. The hydroxyl radical is a transient but highly reactive species and that oxidize cellular macromolecules resulting in tissue damage (Harper 674)

Question 2

The extreme toxicity of iron is largely a consequence of its ability to:
A. bind to albumin
B. generate ROS
C. oxidize NADH
D. NOTA

Answer 2

B. generate ROS

Question 3

Which organ synthesized the transport plasma protein of iron?
A. Brain
B. Kidney
C. Liver
D. Muscles

Answer 3

C. Transferrin is a glycoprotein synthesized by the liver

• a beta1-globulin
• 76 kDa
• has 2 high affinity binding sites for Fe3+

Question 4

All of the following is true of Transferrin except:
A. It is a beta1-globulin
B. Its molecular mass is approximately 76 kDa
C. It has 3 high affinity binding sites for Fe3+
D. It takes the form of holotransferrin when fully occupied by Fe3+
E. Its glycosylation is impaired in chronic alcoholism

Answer 4

C is wrong since it contains only 2 high-affinity binding sites for Fe3+

Question 5

The H substance which is the blood group substance of type O individuals is characterized as having this sugar attached to the terminal sugar of the precursor?

a. Fructose
b. Fucose
c. Galactose
d. Glucose

Answer 5

B. Fucose

H substance

• formed by the action of a fucosyltransferase coded for the H locus
• catalyzes the addition of the terminal fucose in an alpha1→2 linkage onto the terminal Gal residue of its precursor

Question 6

All of the following are correct regarding H substance except:
A. Found in persons with type O blood
B. Precursor for both A and B substance
C. Adds terminal fucose in an alpha 1→2 linkage on the terminal glucose
D. Individuals with hh genotype cannot generate H substance

Answer 6

C. should be galactose

Question 7

Superoxide is formed through which of the following?
A. Cytochrome P450 reaction in xenobiotics
B. in ETC Complexes III and IV
C. in the Xanthin oxidase reaction in Purine degradation
D. AOTA
E. NOTA

Answer 7

D. AOTA

Question 8

Which superoxide is produced in neutrophils during respiratory burt?

Answer 8

superoxide

Question 9

The iron in the 4 pyrrole rings of an Hgb is in what state?
A. Ferrous
B. Ferric

Answer 9

A. Ferrous

Question 10

Enzyme that facilitates the reduction of the ferric iron into ferrous state in methemoglobin

Answer 10

NADH-cytochrome b5 methemoglobin reductase or Methemoglobin reductase utilizing cytochrome b5

Question 11

Symptom manifested by patients lacking in Methemoglobin reductase

Answer 11

Cyanosis due to methemoglobinemia of >10%

Question 12

If methemoglobinemia results from mutations in hemoglobin itself, which amino acid residues are involved?

Answer 12

proximal and distal histidine

- makes iron more susceptible to oxidations

Question 13

All known carriers of Methemoglobinemia gene are:
A. Heterozygotes
B. Homozygotes

Answer 13

A. Heterozygotes

Question 14

Reducing agents for methemoglobinemia:

Answer 14

Vitamin C and Methylene blue

Question 15

Enzyme that breaks down H2O2 to O2 and H2O in peroxisomes of liver
A. Catalase
B. Glutathione peroxidase
C. Vitamin C
E. Vitamin E

Answer 15

A. Catalase

Question 16

Which reducing equivalent is needed for the reduction of glutathione?
A. FADH2
B. NADH
C. NADPH
D. AOTA

Answer 16

C. NADPH from PPP

catalyzed by Glutathione reductase

Question 17

iron is absorbed in what state?

Answer 17

Ferrous