Sickle Haem Flashcards
1
Q
- What is the primary source of haem in the body?
A
- Haemoglobin in senescent red blood cells removed from circulation by the reticuloendothelial system especially in the spleen
- Cytochrome P450 group of enzymes
- Other haem proteins
- Haem from ineffective erythropoiesis (pernicious anaemia and thalassaemia)
2
Q
- Which of the following is NOT listed as a source of haem?
A
D
3
Q
- In haem catabolism, which protein group is responsible for removing senescent erythrocytes?
A
Cytochrome P450 group of enzymes
4
Q
- Which enzyme initiates the breakdown of haem?
A
Haem oxygenase
5
Q
- Haem oxygenase is classified as which type of enzyme?
A
B
6
Q
- What specific chemical bond does haem oxygenase cleave in the haem molecule?
A
C
7
Q
- Which reaction uniquely releases carbon monoxide (CO) in vivo?
A
C
8
Q
- What is the immediate product formed from the haem oxygenase–mediated reaction?
A
B
9
Q
- Which enzyme catalyzes the reduction of biliverdin to bilirubin?
A
B
10
Q
- How is bilirubin transported in the bloodstream?
A
A
11
Q
- Where does bilirubin conjugation take place?
A
B
12
Q
- What molecule is conjugated to bilirubin during the conjugation reaction?
A
C
13
Q
- How many UDP glucuronate molecules are used to conjugate one bilirubin molecule?
A
B
14
Q
- Which conjugated product is formed after bilirubin is esterified with glucuronic acid?
A
B
15
Q
- What is the fate of bilirubin diglucuronide in the intestine?
A
C
16
Q
- Following deconjugation in the intestine, free bilirubin is reduced to which colorless compound?
A
B
17
Q
- Urobilinogens can be oxidized to form which colored compounds?
A
A
18
Q
- Which of the following is a prehepatic cause of jaundice?
A
C
19
Q
- Neonatal jaundice is most commonly due to which factor?
A
A
20
Q
- Hepatic jaundice can be caused by genetic errors in which process?
A
B
21
Q
- Which condition is most likely to cause post-hepatic jaundice?
A
C
22
Q
- In the conjugation reaction of bilirubin, what is the main biochemical change that increases its solubility?
A
B
23
Q
- The water-soluble conjugated bilirubin is known as:
A
B
24
Q
- What therapeutic intervention uses blue wavelengths of light to treat neonatal jaundice?
A
A
25
25. Which of the following statements best summarizes the sequence in haem catabolism?
A
26
26. In haem catabolism, what is the role of haem oxygenase beyond haem cleavage?
B
27
27. Which enzyme acts immediately after haem oxygenase in the haem degradation pathway?
B
28
28. How does the conjugation of bilirubin facilitate its excretion?
C
29
29. Which molecule binds bilirubin in the bloodstream for transport to the liver?
B
30
30. Which of the following best explains the importance of bilirubin conjugation in the liver?
A
31
31. What is the consequence of bacterial deconjugation of bilirubin diglucuronide in the intestine?
B
32
32. Which group of conditions falls under prehepatic causes of jaundice?
B
33
33. In hepatic jaundice, which of the following is a common etiological factor?
B
34
34. Which genetic syndrome is characterized by defects in bilirubin conjugation?
D
35
35. Which of the following best describes the product of the bilirubin conjugation reaction?
B
36
36. How many molecules of UDP glucuronate are required to conjugate one molecule of bilirubin?
B
37
37. Which intestinal process contributes to the elimination of bilirubin metabolites?
B
38
38. What is the biochemical basis for the use of phototherapy in neonatal jaundice?
B
39
39. Which of the following is a hallmark laboratory finding in prehepatic jaundice?
B
40
40. In which scenario would you most likely observe an increase in urobilinogen levels in the urine?
B
41
41. What is the significance of the bile excretion pathway in bilirubin metabolism?
B
42
42. Which process during haem catabolism is directly responsible for the production of carbon monoxide?
B
43
43. Which one of the following best describes the enterohepatic circulation in the context of bilirubin metabolism?
"Unconjugated bilirubin is directly excreted via sweat."
44
44. Which of the following hepatic conditions might lead to impaired bilirubin conjugation?
C
45
45. Which factor does NOT contribute to the classification of jaundice causes?
D
46
46. Assertion: Bilirubin conjugation is essential for its excretion. Reason: Conjugation with glucuronic acid renders bilirubin water-soluble.
A
47
47. Assertion: Haem oxygenase only cleaves protein-bound haem. Reason: Free protoporphyrin IX is not a substrate for haem oxygenase.
A
48
48. In schematic diagrams of haem catabolism, which step directly leads to the production of a pigment responsible for the color of bile?
B
49
49. Which enzyme in haem catabolism is solely responsible for the release of carbon monoxide (CO) during the breakdown of haem?
B
50
50. In the context of haem catabolism, which of the following most accurately describes the role of bacterial hydrolases in the gut?
"They inactivate haem oxygenase."
51
51. Assertion: Phototherapy is effective in neonatal jaundice. Reason: Blue light converts insoluble unconjugated bilirubin into soluble photoisomers that can be excreted.
A
52
52. In diagram-based models of haem catabolism, which step is represented as the critical modification that prevents the reabsorption of bilirubin from the intestine?
B
53
53. Which aspect of the conjugation reaction most contributes to the water solubility of bilirubin?
B
54
54. In a clinical diagram of bilirubin metabolism, an accumulation of unconjugated bilirubin would most likely indicate a defect in which process?
B
55
55. Which description best explains why neonatal livers are less efficient at conjugating bilirubin?
B
56
56. Assertion: Prehepatic jaundice results primarily from increased haem breakdown. Reason: Hemolytic disorders increase the load of unconjugated bilirubin delivered to the liver.
A
57
57. In schematic representations of haem catabolism, which metabolite is the first pigmented product formed from haem?
B
58
58. Which step in haem catabolism is directly responsible for the formation of bilirubin diglucuronide?
C
59
59. Which condition would most likely be depicted in a diagram showing high levels of conjugated bilirubin in serum?
B
60
60. Assertion: Bacterial action in the gut is essential for normal bilirubin excretion. Reason: Bacterial hydrolases remove glucuronide residues, converting bilirubin diglucuronide to urobilinogens.
A
61
61. Which of the following diagrammatic steps best represents the transition from water-insoluble to water-soluble bilirubin?
C
62
62. In a schematic overview of jaundice causes, which category is associated with increased production of unconjugated bilirubin?
A
63
63. Which of these conditions is an example of post-hepatic jaundice due to obstruction of bile flow?
C
64
64. In the context of bilirubin metabolism, which of the following best explains the formation of photoisomers during phototherapy?
"Blue light oxidizes bilirubin to biliverdin."
65
65. Which of the following best summarizes the fate of bilirubin diglucuronide once it reaches the intestine?
"It is converted directly into urobilins without further modification."
66
66. Assertion: The conjugation of bilirubin is a key protective mechanism against bilirubin toxicity. Reason: Conjugated bilirubin is water-soluble and can be easily excreted.
A
67
67. In diagrams of haem catabolism, which enzyme’s activity is typically depicted as the point at which free haem is converted into biliverdin?
A
68
68. Which molecule is used as a carrier for bilirubin in the blood, as often shown in pathway diagrams?
C
69
69. In cases of hepatic jaundice caused by viral hepatitis, which process in bilirubin metabolism is most likely impaired?
B
70
70. Which of the following is a direct consequence of impaired UDP glucuronyl transferase activity?
A
71
71. Assertion: Neonatal jaundice is often self-limiting. Reason: The immature conjugating capacity of the liver in neonates gradually improves after birth.
A
72
72. In schematic diagrams of haem catabolism, what is the primary role of biliverdin reductase?
B
73
73. Which process depicted in haem catabolism explains the generation of color in bile?
B
74
74. In the context of haem catabolism, which statement best differentiates prehepatic from post-hepatic jaundice?
"Prehepatic is caused by liver damage
75
75. Which diagram-based step best represents the final modification that prepares bilirubin for excretion in the intestines?
C
