Essential Biochemistry - Protein Metabolism (Section 9)
1
Which amino acid is a precursor to the neurotransmitter serotonin?
2
Which of the following are reactants/substrates in the Urea Cycle?
3
Which process describes the movement of amino groups between molecules?
4
What process removes the amino group from an amino acid?
5
Which of the following amino acids is glucogenic?
6
During what physiological state is a positive nitrogen balance typically observed?
7
What is the primary metabolic role of alanine?
8
In the synthesis of melanin, what is the precursor of DOPA?
9
Which of the following amino acids are converted to pyruvate?
10
Norepinephrine is converted to epinephrine by:
11
What is a key enzyme in the degradation of histidine?
12
What is the process by which amino groups are transferred between amino acids?
13
Which of the following is an essential amino acid?
14
What is the role of BH4 in the metabolism of amino acids?
Answer(B)
Acts as a cofactor for hydroxylases
15
Which amino acid is converted to pyruvate in its degradation?
16
Which amino acid gives rise to alpha-ketoglutarate during degradation?
17
Which is the initial reaction in tryptophan metabolism?
18
What is the primary function of glutamine synthetase?
Answer(B)
Converting glutamate to glutamine
19
Which of the following is a key intermediate in the degradation pathway for lysine?
20
Which of the following pathways occurs in part in the mitochondria and in part in the cytoplasm?
21
Which of the following is a characteristic of the urea cycle?
Answer(A)
It occurs in the mitochondria and cytosol of liver cells.
22
Where are amino acids primarily absorbed?
23
Carboxypeptidase contains which of the following mineral?
24
Which of the following is a precursor for the synthesis of carbamoyl phosphate in the urea cycle?
25
Which of the following is NOT a step in the digestion of protein in the stomach?
26
Which enzyme activates pepsinogen?
27
Which enzyme catalyzes the first committed step of the urea cycle?
Answer(B)
Carbamoyl phosphate synthetase I
28
All of the following statements are true in the transamination of amino acids, except:
Answer(D)
All amino acids can undergo transamination
29
Which of the following amino acids are involved in the synthesis of creatine?
30
What compound is formed by the oxidation of tryptophan in the kynurenine pathway?
31
Which of the following is an important product of the kynurenine pathway?
32
The methylene group, transferred to glycine in converting it to serine, comes from:
33
In what situation is a negative nitrogen balance most often seen?
Answer(C)
During prolonged starvation
34
What is the main metabolic role of aspartate?
35
Which of the following are symptoms of hyperammonemia?
36
What are the metabolic functions of dopamine?
37
Which of the following amino acids can undergo deamination by dehydration?
38
What is the role of tetrahydrofolate (THF) in one-carbon metabolism?
Answer(A)
Accepting and donating one-carbon units
39
The key reactions of tyrosine metabolism include
40
What is the primary function of the serine hydroxymethyltransferase?
Answer(B)
To transfer a one-carbon unit from serine to tetrahydrofolate.
41
Which of the following amino acids is directly involved in the synthesis of purines?
42
What is the purpose of deamination?
43
Which amino acid is converted to dopamine?
44
What is the function of BH4?
Answer(A)
To hydroxylate phenylalanine
45
What is the role of enterocytes in the absorption of amino acids?
46
Which of the following is a characteristic of albinism?
47
What is the main role of glutamate dehydrogenase?
Answer(B)
To remove ammonia from glutamate.
48
Which of the following is the precursor for synthesis of serotonin?
49
Which of the following amino acids can be converted into glucose via gluconeogenesis?
50
What are the precursors to urea?
