The post Disorders of Hemoglobin Metabolism and MCQs for NEET, GPAT, NORCET, GATE, CSIR NET Exams appeared first on Gpatindia: Pharmacy Jobs, Admissions, Scholarships, Conference,Grants, Exam Alerts.
]]>Porphyria is a group of disorders which are resulting from the deficiency of enzymes required for the biosynthesis of heme. This leads to the accumulation and increased excretion of porphyrins, ALA and PBG. Porphyria can be caused genetically or acquired.
The most common form of acquired porphyria is due to lead poisoning, delta-ALA dehydratase. Thus during lead poisoning, production of heme decreases and causes anemia.
Classification of porphyria
The porphyria are classified on the basis of the organ and cells which are most affected like bone marrow and liver. Thus porphyria are classified in two main classes
Six major types of porphyria fall in these two categories. These are described in the below given table.
Class | Types | Enzyme defect |
Hepatic | Acute intermittent porphyria | Uroporphyrinogen-1 synthase |
Erythropoietic | Congenital erythropoietic | Uroporphyrinogen-3 co-synthase |
Hepatic | Porphyry cutanea porphyria | Uroporphyrinogen decarboxylase |
Hepatic | Hereditary co-proporphyria | Coproporphyrinogen oxidase |
Hepatic | Variegate porphyria | Protoporphyrinogen oxidase |
Erythropoietic | Protoporphyria | Ferrochelatase |
Causes:- Exposure to sunlight, certain hormonal drugs, dieting or fasting, recreational drug, smocking, alcohol consumption, physical stress.
Treatment:-
Diseases or condition that interfere the bilirubin metabolism causes a rise in serum concentration. When bilirubin in blood exceeds the value of 1mg/dl, then it causes hyperbilirubinemia .
In such situations, bilirubin tends to accumulate in the blood, and when its concentration reaches 2.2mg/dl to 5mg/dl then it diffuses into the tissues. The skin and sclera of the eye becomes yellow due to excessive bilirubin. This condition is known as jaundice or icterus .
Hyperbilirubinemia may be acquired or genetic:
Acquired hyperbilirubinemia includes:
Genetic hyperbilirubinemia includes:
Causes:-
Treatment:-
1. Which compound is accumulated during porphyrias?
A. ALA
B. PBG
C. Porphyrins
D. All of the above
2. What is the cause of porphyria?
A. Genetic cause
B. Acquired cause
C. Both
D. None
3. Which type of poisoning causes acquired porphyria?
A. Cyanide poisoning
B. Lead poisoning
C. Arsenic poisoning
D. Both A and C
4. In protoporphyria, which enzyme is defected?
A. Protoporphyrinogen oxidase
B. Heme synthase
C. Coproporphyrinogen oxidase
D. None of the above
5. Which of the following is the main symptom of porphyria?
A. Mental retardation
B. Photosensitivity
C. Jaundice
D. All of the above
6. Variegate porphyria comes under which class?
A. Hepatic
B. Erythropoiesis
C. Both
D. None
7. What is the saturation value after which hyperbilirubinemia is caused?
A. 0.1 mg/dl
B. 2mg/dl
C. 1mg/dl
D. 0.5mg/dl
8. What happens during jaundice?
A. Abdominal pain
B. Confusion
C. Yellowish skin and eye
D. All of the above
9. Match the following disorder and its cause-
a. Hepatic jaundice 1. Defective enzyme for heme synthesis
b. Hemolytic jaundice 2. Blockage of bile duct
c. Obstructive jaundice 3. Incompatible blood transfusion
d. Porphyria 4. Toxic chemicals
10. What happens during hemolytic jaundice?
A. Increased breakdown of hemoglobin
B. Defect in liver cell
C. Defective bile passage within liver
D. Obstruction in passage between liver and intestine
11. Which type of jaundice is caused due to cirrhosis?
A. Hemolytic jaundice
B. Hepatic jaundice
C. Obstructive jaundice
D. Rotor syndrome
12. Absence of bilirubin in urine is the clinal feature of which type of jaundice?
A. Hemolytic jaundice
B. Hepatic jaundice
C. Obstructive jaundice
D. Rotor syndrome
13. Which of the following statement is NOT true?
A. Hepatic jaundice is caused due to drugs
B. Post hepatic jaundice is also known as acholuric jaundice
C. The normal range of unconjugated bilirubin is 0.2 to 0.7 mg/dl
D. Crigler-Najjar syndrome is of 2 types
14. Which of the following comes under inherited hyperbilirubinemia?
A. Hemolytic jaundice
B. Hepatic jaundice
C. Obstructive jaundice
D. None of the above
15. After which value of blood-bilirubin, the bilirubin diffuses into the tissues from blood?
A. 0.1 mg/dl
B. 0.2mg/dl
C. 1mg/dl
D. 4mg/dl
ANSWERS-
1. All of the above
2. Both
3. Lead poisoning
4. Heme synthase
5. Photosensitivity
6. Hepatic
7. 1mg/dl
8. Yellowish skin and eye
9. a – 4 b – 3 c – 2 d – 1
10. Increased breakdown of hemoglobin
11. Hepatic jaundice
12. Hemolytic jaundice
13. Post hepatic jaundice is also known as acholuric jaundice
14. None of the above
15. 4mg/dl
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REFERENCE:– 1. Pankaja Naik- Biochemistry; 4th edition; page no:- 315, 316, 319, 320
The post Disorders of Hemoglobin Metabolism and MCQs for NEET, GPAT, NORCET, GATE, CSIR NET Exams appeared first on Gpatindia: Pharmacy Jobs, Admissions, Scholarships, Conference,Grants, Exam Alerts.
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