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Essential Biochemistry - Protein Metabolism (Section 6)

1
Which amino acid provides a carbon skeleton for the synthesis of glucose?
Answer
(A)
Alanine
2
Which amino acid is involved in the formation of glutathione?
Answer
(B)
Cysteine
3
Which component takes part in the urea cycle?
Answer
(B)
Ammonia
4
In transamination reactions, what does the amino group transfer to?
Answer
(B)
A keto acid
5
Which of the following is an important precursor for the synthesis of serotonin?
Answer
(C)
Tryptophan
6
Phenylketonuria results due to the absence of the enzyme:
Answer
(B)
Phenylalanine hydroxylase
7
What is the major source of the one-carbon group used in the synthesis of thymidylate?
Answer
(C)
Folate
8
What is the primary role of HCl in protein breakdown in the stomach?
Answer
(C)
To unfold protein structure
9
Which of the following is a result of high levels of branched-chain amino acids?
Answer
(B)
Maple syrup urine disease
10
Which of the following diseases is caused by the deficiency of cystathionine beta-synthase?
Answer
(C)
Homocystinuria
11
What enzyme deficiency is often seen in PKU?
Answer
(A)
Phenylalanine hydroxylase
12
Which of the following is true about the metabolism of histidine?
Answer
(D)
All the above
13
What is the main function of the urea cycle?
Answer
(A)
To remove ammonia from the body.
14
What are the end products of the degradation of lysine?
Answer
A
B
15
What is the main metabolic defect causing maple syrup urine disease?
Answer
(B)
Deficiency in branched-chain alpha-keto acid dehydrogenase
16
Where does most protein digestion and absorption occur?
Answer
(C)
Jejunum
17
All of the following are intermediates formed by amino acid degradation, except:
Answer
(D)
Citrate
18
What is the transfer of an amino group from an amino acid to a keto acid called?
Answer
(B)
Transamination
19
Which of the following is NOT a substrate used in urea synthesis?
Answer
(D)
Glucose
20
Which of the following is the main function of histidine?
Answer
(C)
Precursor for histamine
21
Which amino acids are glucogenic?
Answer
A
D
22
Which disease is characterized by the accumulation of branched-chain alpha-keto acids?
Answer
(B)
Maple syrup urine disease
23
What is the function of the urea cycle?
Answer
(B)
To detoxify ammonia
24
Which amino acid undergoes decarboxylation to form histamine?
Answer
(B)
Histidine
25
What is the role of carbaomyl phosphate synthetase I (CPS I) in the Urea Cycle?
Answer
(A)
Catalyzes first step of the cycle
26
What is the role of asparagine in the body?
Answer
(B)
Building block of proteins
27
What is the primary purpose of deamination?
Answer
(B)
To remove the amino group
28
What process does deamination accomplish in terms of amino acids?
Answer
(B)
Amino group removal
29
Which of the following is/are a ketogenic amino acid(s)?
Answer
(D)
Leucine
30
Which amino acid is the precursor for the synthesis of serine?
Answer
(A)
Glycine
31
Which of the following is the major site of urea synthesis?
Answer
(B)
Liver
32
Which vitamin is essential for the methylation of homocysteine to form methionine?
Answer
(B)
Vitamin B12
33
What is the primary function of cystathionine gamma-lyase?
Answer
(A)
Convert homocysteine to cysteine
34
Which amino acids can be directly converted to acetyl-CoA?
Answer
A
B
35
Which of the following is a function of serotonin?
Answer
(A)
Regulation of body temperature
36
What is the significance of serine hydroxymethyltransferase?
Answer
A
B
C
37
What enzyme catalyzes the conversion of homocysteine to cysteine?
Answer
(B)
Cystathionine gamma-lyase
38
In alkaptonuria, which of the following accumulates abnormally in the urine?
Answer
(C)
Homogentisate
39
What happens during prolonged starvation regarding nitrogen balance?
Answer
(C)
Negative nitrogen balance
40
Following enzymes are endopeptidase, except:
Answer
(D)
Aminopeptidase
41
What component takes part in the urea cycle to remove excess nitrogen?
Answer
(B)
Ammonia
42
What are the final products of the urea cycle?
Answer
(C)
Urea and fumarate
43
Which of the following amino acids is a nonessential amino acid?
Answer
(C)
Glutamate
44
Which of the following amino acids is NOT involved in the urea cycle?
Answer
(D)
Phenylalanine
45
In Maple-syrup urine disease, which of the following compounds is accumulated?
Answer
(C)
Branched chain α-keto acids
46
Which amino acid is a precursor to dopamine?
Answer
(B)
Tyrosine
47
What is the primary function of glutamate dehydrogenase?
Answer
(B)
Remove ammonia from glutamate
48
What process is primarily affected by defects in the branched-chain alpha-keto acid dehydrogenase complex?
Answer
(C)
Breakdown of branched-chain amino acids
49
What is the role of bicarbonate in the small intestine?
Answer
(B)
Neutralize gastric acid
50
What is the source of the one-carbon unit in the synthesis of thymidine?
Answer
(A)
Folate