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Essential Biochemistry - Protein Metabolism (Section 10)

1
Where does the majority of protein digestion occur?
Answer
(C)
Jejunum
2
What disease results from a deficiency in cystathionine beta-synthase?
Answer
(C)
Homocystinuria
3
Which of the following is involved in the regulation of blood pressure?
Answer
(A)
Histamine
4
What enzyme is responsible for triggering the activation of trypsinogen?
Answer
(B)
Enteropeptidase
5
What is the significance of hyperammonemia?
Answer
A
B
C
6
What is the precursor for synthesis of ornithine?
Answer
(B)
Arginine
7
Which of the following compounds is involved in the synthesis of creatinine?
Answer
(D)
All of the above
8
Which of the following is NOT an endopeptidase?
Answer
(D)
Aminopeptidase
9
Which amino acid is directly converted to pyruvate?
Answer
(A)
Alanine
10
Which of the following is the primary role of asparagine?
Answer
(B)
As a building block for proteins.
11
What molecule accepts amino groups in most transamination reactions?
Answer
(B)
α-ketoglutarate
12
Which molecule is a common acceptor of amino groups in transamination reactions?
Answer
(C)
α-ketoglutarate
13
In the synthesis of cysteine from methionine, which molecules are involved?
Answer
A
C
D
14
What is the role of glutamate dehydrogenase in amino acid metabolism?
Answer
(B)
Catalyzes the oxidative deamination of glutamate
15
Which of the following conditions leads to the accumulation of homocysteine in the blood?
Answer
(A)
Homocystinuria
16
Tetrahydrobiopterin is used as coenzyme in the metabolism of:
Answer
(B)
Phenylalanine
17
Which of the following amino acids is exclusively ketogenic?
Answer
(A)
Leucine
18
Which of the following amino acids is a precursor to proline synthesis?
Answer
(A)
Glutamate
19
Which condition is characterized by a negative nitrogen balance?
Answer
(C)
Starvation
20
What is the final product of oxidative deamination of amino acids?
Answer
(A)
Ammonia
21
What is the main waste product of amino acid catabolism that is excreted in urine?
Answer
(C)
Urea
22
What are the three stages of the complete catabolism of amino acids?
Answer
(A)
Transamination, deamination, urea cycle
23
Which of the following is directly converted to pyruvate during amino acid metabolism?
Answer
(A)
Serine
24
What is the role of serine in purine and pyrimidine synthesis?
Answer
(B)
It provides the carbon atoms.
25
Which amino acids can be converted to pyruvate?
Answer
A
B
C
26
What does the urea cycle yield?
Answer
A
B
C
27
What is the fate of glycine?
Answer
(D)
It may be catabolized to yield formate, and CO2
28
Where does the urea cycle primarily occur?
Answer
(B)
Liver
29
The fate of ammonia in brain is:
Answer
(B)
Conversion to glutamate
30
When does a negative nitrogen balance typically happen?
Answer
(C)
During starvation
31
In what form is ammonia transported in the blood?
Answer
(C)
Glutamine
32
Which of the following amino acids serves as a source for the synthesis of creatine?
Answer
(B)
Arginine
33
Which of the following processes utilizes a one-carbon unit?
Answer
A
B
34
What is the role of the urea cycle?
Answer
(A)
Removal of ammonia
35
Which of the following are glucogenic amino acids?
Answer
A
C
36
Which amino acid is converted to histamine?
Answer
(A)
Histidine
37
What is the process known as transamination?
Answer
(A)
Amino group transfer
38
Which of the following is an example of an exopeptidase?
Answer
(C)
Aminopeptidase
39
Which of the following amino acids is NOT metabolized by the transamination reaction?
Answer
(C)
Histidine
40
Which of the following amino acid cannot undergo transamination?
Answer
(A)
Lysine
41
What is the metabolic fate of aspartate?
Answer
(B)
Transamination to form oxaloacetate
42
What is the main role of serine hydroxymethyltransferase?
Answer
(B)
To transfer a one-carbon unit.
43
Which of the following statements is true regarding the urea cycle?
Answer
(A)
It occurs exclusively in the liver.
44
Which of the following molecules are required for the urea cycle?
Answer
A
B
C
D
45
What is the primary function of asparaginase in cancer treatment?
Answer
(B)
To deplete asparagine, starving cancer cells
46
Which of the following molecules directly participate in the first step of the urea cycle?
Answer
A
B
D
47
Which amino acid is primarily involved in the formation of collagen?
Answer
(B)
Proline
48
What's the major role of HCl during protein digestion in the stomach?
Answer
(C)
To denature proteins
49
Cystinuria is due to defective carrier transport of which amino acids?
Answer
(A)
Cysteine, arginine, lysine, and ornithine
50
What is the metabolic role of alanine?
Answer
(A)
Involved in gluconeogenesis