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Essential Biochemistry - Hemoglobin Metabolism (Section 2)

1
The normal brown and red color of feces results from the presence of
Answer
(A)
Stercobilin
2
Which of the following is a key function of bilirubin?
Answer
(A)
To act as an antioxidant
3
What enzyme is deficient in acute intermittent porphyria?
Answer
(C)
Porphobilinogen deaminase
4
What is the function of bile?
Answer
(B)
Emulsification of fats
5
What is the function of ferrochelatase in heme synthesis?
Answer
(A)
Adds iron to protoporphyrin IX
6
Which enzyme deficiency causes hepatic porphyria?
Answer
(C)
Uroporphyrinogen decarboxylase
7
What process occurs in the liver during bilirubin metabolism?
Answer
A
B
C
8
Which is an example of a disorder of heme biosynthesis?
Answer
(A)
Porphyria
9
The the limiting reaction in heme synthesis is catalyzed by:
Answer
(A)
ALA-synthase
10
Which of the following is true regarding the conjugated bilirubin?
Answer
(A)
Water-soluble and can be excreted in urine
11
In Gilbert's syndrome, which process is primarily affected?
Answer
(B)
Bilirubin conjugation
12
Which enzyme is deficient in acute intermittent porphyria?
Answer
(C)
Porphobilinogen deaminase
13
Which condition results in an increased amount of unconjugated bilirubin?
Answer
A
B
D
14
Which enzyme is essential for conjugation of bilirubin in the liver?
Answer
(A)
Uridine diphosphate glucuronosyltransferase (UGT)
15
Which of the following is a clinical symptom of porphyria?
Answer
(C)
Photosensitivity
16
Which of the following conditions is associated with decreased bilirubin conjugation?
Answer
(B)
Gilbert's syndrome
17
Acute intermittent porphyria is accompanied by increased urinary excretion of
Answer
(A)
Porphobilinogen
18
Which of the following is NOT a type of jaundice?
Answer
(D)
Renal
19
Which enzyme is deficient in Dubin-Johnson syndrome?
Answer
(B)
Bilirubin canalicular transport protein
20
What is the fate of conjugated bilirubin?
Answer
(B)
Excreted in feces as stercobilin
21
What is the role of bacteria in the intestine regarding bilirubin?
Answer
(B)
Reduce bilirubin
22
What is the primary source of bilirubin?
Answer
(A)
Breakdown of red blood cells
23
The limiting reaction in heme synthesis is catalyzed by:
Answer
(B)
δ-ALA synthase
24
What happens to the unconjugated bilirubin in the blood?
Answer
(B)
It is transported to the liver bound to albumin.
25
Unconjugated bilirubin is mixed mostly in:
Answer
(A)
Hemolytic jaundice
26
In which disorder of bilirubin metabolism is there a defect in the transport of bilirubin out of the liver cells?
Answer
(C)
Dubin-Johnson syndrome
27
In the liver, ______ is converted into bilirubin diglucuronide.
Answer
(A)
Bilirubin
28
Which of the following are the side chains of the porphyrin ring in four different ways?
Answer
(D)
All of the above
29
What is the function of UDP-glucuronosyltransferase?
Answer
(A)
Conjugation of bilirubin
30
Which of the following is a feature of unconjugated hyperbilirubinemia?
Answer
(D)
Increased levels of unconjugated bilirubin
31
What is the type of jaundice that is associated with an increase in unconjugated bilirubin?
Answer
(A)
Hemolytic jaundice
32
What is the fate of stercobilinogen?
Answer
(B)
Excreted in the feces
33
The normal color of feces is mainly due to?
Answer
(C)
Stercobilin
34
What is the term for elevated bilirubin in the blood?
Answer
(B)
Jaundice
35
Which of the following is a characteristic of hemolytic jaundice?
Answer
A
C
36
Which type of jaundice is often associated with pale stools?
Answer
(C)
Obstructive jaundice
37
Which enzyme is defective in Crigler-Najjar syndrome?
Answer
(B)
UDP-glucuronosyltransferase
38
The major portion of urobilinogen which remains within intestinal lumen is:
Answer
(B)
Reduced further in the intestine by intestinal bacteria
39
In the intestine, unconjugated bilirubin is converted to:
Answer
(A)
Urobilinogen
40
The enzyme that adds iron to protoporphyrin IX to form heme is:
Answer
(B)
Ferrochelatase
41
The normal serum bilirubin concentration?
Answer
(D)
All of the above
42
The process of bilirubin conjugation primarily occurs in which organ?
Answer
(B)
Liver
43
The normal brown and color of feces results from the presence of:
Answer
(A)
Stercobilin
44
Where does the conjugation of bilirubin occur?
Answer
(B)
Liver
45
What is the substrate for bilirubin conjugation in the liver?
Answer
(C)
Unconjugated Bilirubin
46
The main biochemical feature of hepatocellular jaundice is:
Answer
A
C
D
47
Acute intermittent porphyria is accompanied by increased urinary excretion of:
Answer
(A)
Porphobilinogen
48
Which of the following is a common symptom in all types of jaundice?
Answer
(C)
Yellowing of the skin and eyes
49
The first step in the biosynthesis of porphyrins is the condensation of:
Answer
(A)
glycine and succinyl CoA to form 5-aminolevulinic acid.
50
Which compound is responsible for the normal yellow color of urine?
Answer
(B)
Urobilin