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Quick Biochemistry - Proteins And Protein Metabolism (Section 2)

1
What substance disrupts the hydrogen bonds within peptide linkages in a protein molecule?
Answer
(A)
Guanidine
2
What is the axial ratio (length to breadth) typically found in globular proteins, which feature a completely folded, coiled polypeptide chain?
Answer
(A)
Less than 10 and generally not greater than 3-4
3
What is the characteristic axial ratio of fibrous proteins?
Answer
(D)
Greater than 10
4
How many amino acid residues are typically found in each complete turn of an α-helix?
Answer
(A)
3.6
5
What is the distance covered by one complete turn of an α-helix, measured in nanometers?
Answer
(B)
0.54
6
In an α-helix, how far does each amino acid residue advance along the helix, measured in nanometers?
Answer
(A)
0.15
7
How many helices are typically present in a collagen molecule?
Answer
(C)
3
8
What type of protein structure do the α-helix and β-pleated sheet represent?
Answer
(B)
Secondary structure
9
Which statement accurately describes the α-helix of proteins?
Answer
(C)
A non-periodic structure
10
What primarily stabilizes an α-helix of a polypeptide chain at its lowest energy level?
Answer
(A)
By hydrogen bonds formed between the H of peptide N and the carbonyl O of the residue
11
The scientists who proposed the configurations of both α-helix and β-pleated sheet structures in proteins were
Answer
(B)
Pauling and Corey
12
What is the main amino acid found in the primary structure of fibroin, a key protein in silk worm fibers?
Answer
(A)
Glycine
13
Which level of protein structure describes how the entire polypeptide chain folds to create a three-dimensional shape?
Answer
(D)
The overall folding pattern
14
Which of the following processes does not break disulphide bonds in a protein molecule?
Answer
(C)
Denaturation
15
Which protein purification method allows for highly specific separation of a target protein?
Answer
(D)
Affinity chromatography
16
What is the primary consequence of protein denaturation concerning molecular bonds?
Answer
(C)
Destruction of hydrogen bonds
17
Ceruloplasmin belongs to which class of globulins?
Answer
(A)
a₁-globulin
18
Considering electrophoretic mobility and triglyceride content, which lipoprotein moves fastest and has the least triglycerides?
Answer
(D)
HDL
19
Which lipoprotein is involved in the activation of the enzyme LCAT?
Answer
(A)
HDL
20
Which apolipoprotein serves as an activator for the enzyme LCAT?
Answer
(A)
A-I
21
Which apolipoprotein triggers activity in extrahepatic lipoprotein?
Answer
(C)
Apo-C
22
Which apolipoprotein is a key part of chylomicrons?
Answer
(B)
B-48
23
Which apolipoprotein is a key part of VLDL?
Answer
(A)
B-100
24
Which apolipoprotein helps LDL bind to its receptor?
Answer
(B)
B-100
25
In which condition are elevated serum LDL levels often observed?
Answer
(A)
Obstructive jaundice
26
Which lipoprotein is linked to a higher risk of coronary atherosclerosis?
Answer
(A)
LDL
27
Which lipoprotein is linked to a lower risk of coronary atherosclerosis?
Answer
(D)
HDL
28
What is the main biochemical issue in those with familial hypercholesterolemia (type IIa)?
Answer
(D)
Functional deficiency of plasma membrane receptors for LDL
29
What is the underlying biochemical problem in abetalipoproteinemia?
Answer
(A)
Apo-B synthesis
30
Which condition is linked to familial hypertriaacylglycerolemia?
Answer
(A)
Over production of VLDL
31
What is the number of carbon atoms in the fatty acid produced from essential fatty acids during prostaglandin synthesis?
Answer
(C)
20
32
At what positions do all active prostaglandins possess at least one double bond?
Answer
(A)
7 and 8
33
What is a typical range for total phospholipids in plasma?
Answer
(C)
1.8-5.8 mmol/L
34
What is the density range of HDL particles?
Answer
(D)
1.063-1.125
35
Within what density range do beta-lipoproteins fall?
Answer
(C)
1.019-1.063
36
Which density range is characteristic of IDL particles?
Answer
(B)
1.006-1.019
37
Aspirin's activity involves the inhibition of which enzyme?
Answer
(B)
Cyclooxygenase
38
Which enzyme is classified as a 'suicide enzyme'?
Answer
(A)
Cycloxygenase
39
Prostaglandins influence adipose tissue by reducing which process?
Answer
(A)
Lipogenesis
40
What is the optimal pH range for pepsin's enzymatic activity?
Answer
(A)
1.0-2.0
41
What chemical agent transforms pepsinogen into its active form, pepsin?
Answer
(A)
HCI
42
At what pH does the enzyme rennin function most effectively?
Answer
(B)
4.0
43
In what pH range does the enzyme trypsin perform best?
Answer
(C)
5.2-6.2
44
What is the optimal pH environment for the enzyme chymotrypsin?
Answer
(D)
8.0
45
Which enzyme initiates the activation of trypsinogen into active trypsin?
Answer
(A)
Enterokinase
46
Following the action of pepsin on altered proteins, what are the resulting products?
Answer
(A)
Proteoses and peptones
47
Rennin's conversion of casein to paracasein requires the presence of which element?
Answer
(A)
Ca++
48
What is an example of an exopeptidase?
Answer
(D)
Elastase
49
The enzyme trypsin selectively breaks down peptide bonds associated with which type of amino acids?
Answer
(A)
Basic amino acids
50
For which type of peptide bonds is chymotrypsin specifically designed?
Answer
(A)
Uncharged amino acid residues