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Essential Biochemistry - Protein Metabolism (Section 11)

1
What is the importance of the saccharopine pathway?
Answer
(A)
Breakdown of lysine
2
What is the form of ammonia primarily transported in the bloodstream?
Answer
(C)
Glutamine
3
Which of the following can form pyruvate?
Answer
A
B
C
4
Which enzyme is crucial for activating trypsinogen?
Answer
(B)
Enteropeptidase
5
The reactions of urea cycle occur in:
Answer
A
B
6
Which condition is characterized by a positive nitrogen balance?
Answer
(C)
Pregnancy
7
Which of the following amino acids are exclusively ketogenic?
Answer
A
B
8
The amino acid required for synthesis of heme is:
Answer
(C)
Glycine
9
All of the following are synthesized from tyrosine, except:
Answer
(B)
Serotonin
10
What is a characteristic feature of the clinical presentation of cystinuria?
Answer
(B)
Formation of kidney stones
11
Which enzyme is directly involved in the formation of urea?
Answer
(B)
Arginase
12
Which amino acid is the immediate precursor for the synthesis of GABA (gamma-aminobutyric acid)?
Answer
(A)
Glutamate
13
Which of the following amino acids is a precursor for the synthesis of epinephrine and norepinephrine?
Answer
A
D
14
Which enzyme catalyzes the first step in the biosynthesis of melanin?
Answer
(A)
Tyrosinase
15
Which of the following processes does NOT require tetrahydrofolate (THF)?
Answer
(D)
Urea Cycle
16
Which enzyme is vital for activating trypsinogen into trypsin?
Answer
(B)
Enteropeptidase
17
The following enzymes are involved in digestion and absorption of protein, except:
Answer
(B)
Amylase
18
What is the key role of glutathione in cells?
Answer
(B)
Antioxidant defense
19
Which of the following is/are formed from the catabolism of carbon skeletons of amino acids?
Answer
A
B
D
20
Which of the following statements is correct regarding the role of serine hydroxymethyltransferase?
Answer
(D)
All the above.
21
Which of the following amino acids is degraded to yield acetyl-CoA?
Answer
(D)
Proline
22
Which of the following amino acids can be converted into pyruvate?
Answer
A
B
C
23
What is the cause of phenylketonuria (PKU)?
Answer
(B)
Deficiency of phenylalanine hydroxylase
24
Which of the following amino acids is metabolized via the kynurenine pathway?
Answer
(B)
Tryptophan
25
Which of the following amino acids is a substrate in the formation of ornithine?
Answer
(B)
Arginine
26
Where does the first step of the urea cycle take place?
Answer
(B)
Mitochondria
27
Which enzyme is responsible for the activation of trypsinogen in the small intestine?
Answer
(B)
Enteropeptidase
28
Which of the following is the main function of the urea cycle?
Answer
(B)
Removal of ammonia
29
Which of the following is NOT a characteristic of phenylketonuria (PKU)?
Answer
(D)
Excessive production of tyrosine
30
Which of the following are classified as exclusively ketogenic amino acids?
Answer
A
B
31
Which substance is responsible for activating pepsinogen into pepsin?
Answer
(B)
Pepsin
32
What activates the zymogen pepsinogen?
Answer
(B)
Pepsin
33
What is the role of SAM (S-adenosylmethionine) in methionine metabolism?
Answer
(B)
Serves as a methyl group donor
34
Which amino acid is a substrate for the synthesis of proline?
Answer
(A)
Glutamate
35
Which of the following amino acids is NOT glucogenic?
Answer
(C)
Leucine
36
What enzyme converts glutamate to glutamine?
Answer
(C)
Glutamine synthetase
37
Which metabolic defect causes maple syrup urine disease?
Answer
(B)
Defect in branched-chain amino acid metabolism
38
What is the key enzyme involved in the urea cycle?
Answer
(B)
Arginase
39
What is the main function of glutamine in the kidney?
Answer
(A)
Acid excretion
40
Where is most protein digested and absorbed in the body?
Answer
(C)
Jejunum
41
What activates pepsinogen?
Answer
(C)
Pepsin
42
What is the main function of the small intestine in protein digestion?
Answer
(C)
Peptide hydrolysis
43
Which of the following molecules is primarily transported in the blood as a method of carrying nitrogen?
Answer
(C)
Glutamine
44
What is the main function of histamine in the body?
Answer
(C)
Immune response and inflammation
45
Which of the following are branched-chain amino acids?
Answer
A
B
C
46
Which intermediate plays a key role in the urea cycle?
Answer
(D)
Ornithine
47
What is the key metabolic pathway for the degradation of lysine?
Answer
(D)
Saccharopine pathway
48
Which amino acids are utilized in the synthesis of creatine?
Answer
A
B
C
49
Which amino acid is the primary transport form of ammonia in the blood?
Answer
(C)
Glutamine
50
Which of the following are intermediates in the urea cycle?
Answer
A
B
C