Question 1:
Which of the following strategies are used by cells for metabolic regulation? P. Phosphorylation-dephosphorylation Q. Allostery R. Feedback inhibition
A.
P and Q only
B.
P and R only
C.
Q and R only
D.
P, Q and R
Answer: _________
Question 2:
Levinthal's paradox is related to
A.
Protein secretion
B.
Protein degradation
C.
Protein folding
D.
Protein trafficking
Answer: _________
Question 3:
An enzymatic reaction exhibits Michaelis-Menten kinetics. For this reaction, on doubling the concentration of enzyme while maintaining [S] >> [E 0 ],
A.
Both K M and V max will remain the same
B.
K M will remain the same but V max will increase
C.
K M will increase but V max will remain the same
D.
Both K M and V max will increase
Answer: _________
Question 4:
In general, which one of the following statements is NOT CORRECT?
A.
Hydrogen bonds result from electrostatic interactions
B.
Hydrogen bonds contribute to the folding energy of proteins
C.
Hydrogen bonds are weaker than van der Waals interactions
D.
Hydrogen bonds are directional
Answer: _________
Question 5:
Which one of the following statements is CORRECT for enzyme catalyzed reactions? ( ΔG is Gibbs free energy change, K eq is equilibrium constant)
A.
Enzymes affect ΔG, but not K eq
B.
Enzymes affect K eq , but not ΔG
C.
Enzymes affect ΔG and K eq
D.
Enzymes do not affect ΔG or K eq
Answer: _________
Question 6:
ATP biosynthesis takes place utilizing the H + gradient in mitochondria and chloroplasts. Identify the correct sites of H + gradient formation.
A.
Across the outer membrane of mitochondria and across the inner membrane of chloroplast
B.
Across the inner membrane of mitochondria and across the thylakoid membrane of chloroplast
C.
Within the matrix of mitochondria and across the inner membrane of chloroplast
D.
Within the matrix of mitochondria and within the stroma of chloroplast
Answer: _________
Question 7:
An enzyme catalyzes a reaction by
A.
Decreasing the energy of the substrate
B.
Decreasing the activation energy of the reaction
C.
Decreasing product stability
D.
Increasing the activation barrier of the reaction
Answer: _________
Question 8:
Match the entries in Group I with the enzymes in Group II . Group I Group II P. NAD + 1. Glutathione peroxidase Q. Selenium 2. Nitrogenase R. Pyridoxal phosphate 3. Lactate dehydrogenase S. Molybdenum 4. Glycogen phosphorylase
A.
P-3, Q-2, R-4, S-1
B.
P-4, Q-1, R-3, S-2
C.
P-3, Q-1, R-4, S-2
D.
P-3, Q-4, R-2, S-1
Answer: _________
Question 9:
Which one of the following need NOT be conserved in a biochemical reaction?
A.
Total mass
B.
Total moles
C.
Number of atoms of each element
D.
Total energy
Answer: _________
Question 10:
In zinc finger proteins, the amino acid residues that coordinate zinc are
A.
Cys and His
B.
Asp and Glu
C.
Arg and Lys
D.
Asp and Arg
Answer: _________
Question 11:
Match items in Group I with Group II . Group I Group II P. Glycolytic pathway 1. Chloroplast Q. Eukaryotic oxidative metabolism 2. Glyoxysomes R. Glyoxylate cycle 3. Mitochondria S. Calvin cycle 4. Cytosol
A.
P-1, Q-2, R-3, S-4
B.
P-2, Q-3, R-4, S-1
C.
P-4, Q-3, R-2, S-1
D.
P-3, Q-4, R-1, S-2
Answer: _________
Question 12:
The value of ΔG°, if given K ep is 1.7, at 23°C will be
A.
-17.19 kJ mol -1
B.
-19.8 kJ mol -1
C.
+52.82 kJ mol -1
D.
-117.07 kJ mol -1
Answer: _________
Question 13:
Oxidation reduction reactions with positive standard redox potential (ΔE°) have
A.
Positive ΔG°
B.
Negative ΔG°
C.
Positive ΔE +
D.
Negative ΔE +
Answer: _________
Question 14:
Identify the enzyme that catalyzes the following reaction. $$alpha { ext{ - Ketoglutarate}} + NADH + NH_4^ + + {H^ + } o { ext{Glutamate}} + NA{D^ + } + {H_2}O$$
A.
Glutamate synthetase
B.
Glutamate oxoglutarate aminotransferase
C.
Glutamate dehydrogenase
D.
α-Ketoglutarate deaminase
Answer: _________
Question 15:
Match the following photoreceptors with their prosthetic groups and spectral specificity Photoreceptor Moiety that absorbs light Absorption (nm) P. Phototropin 1. Chromobilin a. 400 - 500 Q. Cryptochrome 2. FAD b. 600 - 800 R. Phytochrome 3. FMN c. 500 - 600
A.
P-3-a, Q-2-a, R-1-b
B.
P-1-b, Q-1-a, R-3-b
C.
P-3-a, Q-1-a, R-1-c
D.
P-2-c, Q-1-c, R-1-a
Answer: _________
Question 16:
The degree of inhibition for an enzyme catalyzed reaction at a particular inhibitor concentration is independent of initial substrate concentration. The inhibition follows
A.
Competitive inhibition
B.
Mixed inhibition
C.
Uncompetitive inhibition
D.
Non-competitive inhibition
Answer: _________
Question 17:
Which one of the following amino acid residues will destabilize an α-helix when inserted in the middle of the helix?
A.
Pro
B.
Val
C.
Ile
D.
Leu
Answer: _________
Question 18:
Determine the correctness or otherwise of the following Assertion (A) and Reason (R) . Assertion: Plants convert fatty acids into glucose. Reason: Plants have peroxisomes.
A.
Both (A) and (R) are true but (R) is not the correct reason for (A)
B.
Both (A) and (R) are true and (R) is the correct reason for (A)
C.
(A) is true but (R) is false
D.
(A) is false but (R) is true
Answer: _________
Question 19:
The turnover numbers for the enzymes E1 and E2 are 150 s -1 and 15 s -1 respectively. This means
A.
E1 binds to its substrate with higher affinity than E2
B.
The velocity of reactions catalyzed by E1 and E2 at their respective saturating substrate concentrations could be equal, if concentration of E2 used is 10 times that of E1
C.
The velocity of E1 catalyzed reaction is always greater than that of E2
D.
The velocity of E1 catalyzed reaction at a particular enzyme concentration and saturating substrate concentration is lower than that of E2 catalyzed reaction under the same conditions
Answer: _________
Question 20:
Match the chemicals in Group I with the possible type/class in Group II . Group I Group II P. Picloram 1. Vitamin Q. Zeatin 2. Auxin R. Thiamine 3. Amino Acid S. Glutamine 4. Cytokinin
A.
P-2, Q-4, R-1, S-3
B.
P-4, Q-1, R-2, S-3
C.
P-3, Q-1, R-2, S-4
D.
P-4, Q-2, R-1, S-3
Answer: _________
Question 21:
A protein without its prosthetic group is known as
A.
Apoprotein
B.
Hemoprotein
C.
Holoprotein
D.
lipoprotein
Answer: _________
Question 22:
The active site in the alpha/beta barrel structures is usually located
A.
Inside the barrel
B.
At the amino side of the strands
C.
At the carboxy side of the strands
D.
At any arbitrary site
Answer: _________
Question 23:
Identify the statement that is not applicable to an enzyme catalyzed reaction.
A.
Enzyme catalysis involves propinquity effects
B.
The binding of substrate to the active site causes a strain in the substrate
C.
Enzymes do not accelerate the rate of reverse reaction
D.
Enzyme catalysis involves acid-base chemistry
Answer: _________
Question 24:
Amino acid residue which is most likely to be found in the interior of water-soluble globular proteins is
A.
Threonine
B.
Aspartic acid
C.
Valine
D.
Histidine
Answer: _________
Question 25:
In N-linked glycosylation, the oligosaccharide chain is attached to protein by
A.
Asparagine
B.
Arginine
C.
Serine
D.
Threonine
Answer: _________
Question 26:
Which of the following components constitute a molecular mechanics force field? P. Bond stretching Q. Bond angle bending R. Torsional bond rotation S. Non-bonded interactions
A.
P and Q only
B.
P, Q and R only
C.
P, Q and S only
D.
P, Q, R and S
Answer: _________
Question 27:
Which one of the following is an ABC transporter?
A.
Multidrug resistance protein
B.
Acetylcholine receptor
C.
Bacteriorhodopsin
D.
ATP synthase
Answer: _________
Question 28:
Natural proteins are composed primarily of 20 α-amino acids. Which one of the following statements is true for any of these amino acids in a solution of pH 1.5?
A.
Only the amino group is ionized
B.
Only the carboxylic acid group is ionized
C.
Both amino and carboxylic acid groups are ionized
D.
Both amino and carboxylic add groups are neutral
Answer: _________
Question 29:
Which one of the following statements is NOT true?
A.
In competitive inhibition, substrate and inhibitor compete for the same active site of an enzyme
B.
Addition of a large amount of substrate to an enzyme cannot overcome uncompetitive inhibition
C.
A transition state analogue in enzyme catalyzed reaction increases the rate of product formation
D.
In non-competitive inhibition, K M of an enzyme for its substrate remains constant as the concentration of the inhibitor increases
Answer: _________
Question 30:
Analysis of a hexapeptide using enzymatic cleavage reveals the following result: • Amino acid composition of the peptide is: 2R, A, V, S, Y • Trypsin digestion yields two fragments and the compositions are: (R, A, V) and (R, S, Y) • Chymotrypsin digestion yields two fragments and the compositions are: (A, R, V, Y) and (R, S) • Digestion with carboxypeptidase A yields no cleavage product. Given: Trypsin cleaves at carboxyl side of R. Chymotrypsin cleaves at carboxyl side of Y. Carboxypeptidase A cleaves at amino side of the C-terminal amino acid (except R and K) of the peptide. The correct amino acid sequence of the peptide is:
A.
RSYRVA
B.
AVRYSR
C.
SRYVAR
D.
SVRRYA
Answer: _________
Question 31:
Which one of the following is INCORRECT about protein structures?
A.
A protein fold is stabilized by favorable noncovalent interactions
B.
All parts of a fold can be classified as helices, strands or turns
C.
Two non-covalent atoms cannot be closer than the sum of their van der Waals radii
D.
The peptide bond is nearly planar
Answer: _________
Question 32:
Which one of the following amino acids has three ionizable groups?
A.
Glycine
B.
Leucine
C.
Valine
D.
Lysine
Answer: _________
Question 33:
During lactic acid fermentation, net yield of ATP and NADH per mole of glucose is
A.
2 ATP and 2 NADH
B.
2 ATP and 0 NADH
C.
4 ATP and 2 NADH
D.
4 ATP and 0 NADH
Answer: _________
Question 34:
The reactions leading to the formation of amino acids from the TCA cycle intermediates are
A.
Carboxylation
B.
Isomerization
C.
Transamination
D.
Decarboxylation
Answer: _________
Question 35:
The catalytic efficiency for an enzyme is defined as
A.
$${K_{cat}}$$
B.
$$frac{{{V_{max }}}}{{{k_{cat}}}}$$
C.
$$frac{{{k_{cat}}}}{{{K_M}}}$$
D.
$$frac{{{K_{cat}}}}{{{v_{max }}}}$$
Answer: _________
Question 36:
Which of the following types of molecules act as biological catalysts? P. Protein Q. RNA R. Phospholipid
A.
P and Q only
B.
P and R only
C.
Q and R only
D.
P, Q and R
Answer: _________
Question 37:
Which one of the following amino acids has the highest probability to be found on the surface of a typical globular protein in aqueous environment?
A.
Ala
B.
Val
C.
Arg
D.
Ile
Answer: _________
Question 38:
Determine the correctness or otherwise of the following Assertion (A) and the Reason (R) . Assertion: A very low amount of inhibitor can act as an activator for allosteric enzymes. Reason: Allosteric enzymes follow Michaelis-Menten kinetics.
A.
Both (A) and (R) are true and (R) is the correct reason for (A)
B.
Both (A) and (R) are true but (R) is not the correct reason for (A)
C.
(A) is true but (R) is false
D.
(A) is false but (R) is true
Answer: _________
Question 39:
During photorespiration under low CO 2 and high O 2 levels, O 2 reacts with ribulose 1, 5-bisphosphate to yield
A.
One molecule each of 3-phosphoglycerate and 2-phosphoglycolate
B.
Two molecules of 3-phosphoglycerate
C.
Two molecules of 2-phosphoglycolate
D.
One molecule each of 3-phosphoglycerate and glyoxylate
Answer: _________
Question 40:
The activity of an enzyme is expressed in International Units (IU). However, the SI unit for enzyme activity is Katal. One Katal is
A.
1.66 × 10 4 IU
B.
60 IU
C.
6 × 10 7 IU
D.
10 6 IU
Answer: _________
Question 41:
The molarity of water in a water: ethanol mixture (15 : 85, v/v) is approximately
A.
0.85
B.
5.55
C.
8.5
D.
55.5
Answer: _________
Question 42:
The product(s) resulting from the hydrolysis of maltose is/are
A.
A mixture of α-D-Glucose and β-D-Glucose
B.
A mixture of D-Glucose and L-Glucose
C.
α-D-Glucose only
D.
β-D-Glucose only
Answer: _________
Question 43:
Match the vitamins in Group I with the processes/ reactions in Group II . Group I Group II P. Pantothenic acid 1. Electron transport Q. Vitamin B 2 2. Transfer of 1-C units R. Vitamin B 6 3. Decarboxylation S. Folic acid 4. Fatty acid metabolism 5. Hydrolysis
A.
P-5, Q-2, R-4, S-1
B.
P-4, Q-1, R-3, S-2
C.
P-4, Q-2, R-1, S-3
D.
P-2, Q-1, R-3, S-5
Answer: _________
Question 44:
An alternative to glycolysis pathway is
A.
Glyoxylate pathway
B.
Pentose phosphate pathway
C.
Citric acid cycle
D.
Gluconeogenesis
Answer: _________
Question 45:
Disaccharide molecules that contain β(1→ 4) glycosidic linkage are
A.
Sucrose and maltose
B.
Sucrose and isomaltose
C.
Maltose and isomaltose
D.
Lactose and cellobiose
Answer: _________
Question 46:
The dissociation constant K d for ligand binding to the receptor is 10 -7 M. The concentration of ligand required for occupying 10% of receptors is
A.
10 -6 M
B.
10 -7 M
C.
10 -8 M
D.
10 -9 M
Answer: _________
Question 47:
Which one of the following metabolic processes in mammalian cells does NOT occur in the mitochondria?
A.
Citric acid cycle
B.
Oxidative phosphorylation
C.
Fatty acid β-oxidation
D.
Glycolysis
Answer: _________
Question 48:
The ΔG° for the oxidation of NADH by FAD is
A.
-9.25 kJ mol -1
B.
-103.04 kJ mol -1
C.
+51.52 kJ mol -1
D.
-18.5 kJ mol -1
Answer: _________
Question 49:
Match the high energy compounds in Group I with the biosynthetic pathways for the molecules in Group II . Group I Group II P. GTP 1. Fatty acid Q. UTP 2. Phospholipid R. CTP 3. Protein S. Acyl coenzyme A 4. Peptidoglycan
A.
P-3, Q-2, R-4, S-1
B.
P-2, Q-4, R-3, S-1
C.
P-4, Q-3, R-1, S-2
D.
P-3, Q-4, R-2, S-1
Answer: _________
Question 50:
If a plant is shifted to cold temperature, which of the following changes would take place in its membrane?
A.
Ratio of unsaturated to saturated fatty acids would increase
B.
Ratio of unsaturated to saturated fatty acids would decrease
C.
Absolute amount of both fatty acids would increase keeping the ratio same
D.
Absolute amount of both fatty acids would remain unchanged
Answer: _________
Answer Key
1:
D
2:
C
3:
B
4:
C
5:
A
6:
B
7:
B
8:
C
9:
B
10:
A
11:
C
12:
A
13:
B
14:
C
15:
A
16:
D
17:
A
18:
A
19:
C
20:
A
21:
A
22:
C
23:
C
24:
C
25:
A
26:
D
27:
A
28:
A
29:
C
30:
B
31:
B
32:
D
33:
B
34:
C
35:
C
36:
A
37:
C
38:
C
39:
A
40:
C
41:
C
42:
A
43:
B
44:
B
45:
D
46:
C
47:
D
48:
D
49:
D
50:
A