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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5337_Библиотеки_им_академика_М_И_Перельмана.pdf
89. Pompe’s disease is caused due to deciency of:
A. Lysosomal α-1→4 and 1→6-glucosidase
B. Glucose-6-phosphatase
C. Glycogen synthase
D. Phosphofructokinase
90. The temperature at which the maximum activity
of the enzyme occurs is:
A. Optimum temperature
B. Maximum temperature
C. Minimum temperature
D. None of the above
91. In pentose phosphate pathway, D-ribulose-5phosphate is converted to D-ribose-5-phosphate
by the enzyme:
A. Fumarase B. Ketoisomerase
C. G6PD D. Epimerase
92. The active site of an enzyme remains:
A. At the center of globular proteins
B. Rigid and does not change shape
C. Complementary to the rest of the molecule
D. None of the above
93. In glycogenesis, a branch point in the molecule is
established by the enzyme
A. Amylo[1→ 4][1→ 6] transglucosidase
B. α[1→ 4]α[1→ 4] Glucan transferase
C. Amylo [1→ 6] glucosidase
D. Glycogen synthase
94. One of the causes of galactosemia is the scarcity
of:
A. Galactose-1-phosphate and uridyltransferase
B. Phosphoglucomutase
C. Galactokinase
D. Both B and C
95. One difference between DNA and RNA is:
A. DNA contains thymine and RNA contains uracil
in place of thymine
B. In DNA, adenine pairs with cytosine; in RNA,
adenine pairs with thymine
C. DNA consists of six different nucleotides; RNA
consists of three different nucleotides
96. Zellweger’s syndrome is due to inherited absence
of:
A. Peroxisomes
B. Phospholipase A1
C. Acyl-CoA dehydrogenase
D. Thiolase
97. A person suffering from acute haemolytic
anaemia sensitive to the Fava beans is due to the
insufciency of which of the following enzyme?
A. Pyruvate dehydrogenase
B. G6PD
C. Aconitase
D. Transketolase
98. The amount of ketone bodies in the blood does
not more than:
A. 0.2 mmol/L B. 0.4 mmol/L
C. 1 mmol/L D. 2 mmol/L
99. The enzyme G6PD is found in which of the
following organ?
A. Liver B. Intestine
C. Eye D. Brain
100. Choose one condition out of the following which
is least likely to denature an enzyme.
A. A high temperature
B. An extreme pH
C. A low temperature
D. Heavy metal ions
101. Fructose is converted into sorbitol in the presence
of which of the following enzyme?
A. Sorbitol dehydrogenase
B. Aldose reductase
C. Glucokinase
D. Hexokinase
102. An enzyme that differs in amino acid sequence
but catalyses the same reaction is:
A. Cofactors B. Coenzymes
C. Apoenzymes D. Isoenzymes
103. Which of the following parameters has no effect
on actual change in free energy (∆G)?
A. Temperature
B. Pressure
C. The starting amount of reactant and products
D. pH
104. Essential fructosuria is occurred due to the
deciency of:
A. Phosphohexose isomerase enzyme
B. Aldalose A enzyme
C. Aldolase B enzyme
D. Fructokinase enzyme
105. The difference between enzymes and inorganic
catalysts is that they are highly specic. Which
property of an enzyme is responsible for this
specicity?
A. The insolubility of enzymes.
B. The high molecular weight of enzymes
C. The surface configuration of enzymes
D. None of the above
106. Gastric lipase is converted to its active form in the
presence of:
A. Bile salts B. Mg
C. K+ D. Fe
++
++
107. Choose true statements about the constitution of
membranes.
A. All membranes of eukaryotic cells are composed
of same lipid molecules
B. All biological membranes have cholesterol in
their structure
C. Free fatty acids and triglycerides are major
components of all biological membranes
D. The inner and outer membranes of mitochondria
have different protein compositions
Section 3 Biochemistry
419418
108. In humans, under normal conditions loss of ketone
bodies via urine is usually less than:
A. 1 mg/24 hr B. 4 mg/24 hr
C. 8 mg/24 hr D. 10 mg/24 hr
109. What is the nature of an enzyme?
A. Vitamin B. Lipid
C. Carbohydrate D. Protein
110. Which of the following is the best description of
an enzyme?
A. They allow chemical reactions to proceed very
quickly
B. They increase the rate at which a chemical
reaction approaches equilibrium
C. They make a reaction thermodynamically
favourable
D. All of the above
111. What is an apoenzyme?
A. It is a protein portion of an enzyme
B. It is a non-protein group
C. It is a complete, biologically active conjugated
enzyme
D. It is a prosthetic group
112. Enzymes responsible for ketone body formation
are associated mainly with the:
A. Mitochondria
B. Endoplasmic reticulum
C. Nucleus
D. Golgi apparatus
113. What is the role of an enzyme in an enzymecatalysed reaction?
A. To ensure that the product has more stability as
compared to substrate
B. Make changes in free-energy for making the
reaction more favourable
C. Stimulate the rate at which substrate is changed
into product
D. To make sure that whole of the substrate is
changed into the product.
114. A reversible non-competitive inhibitor binds
reversibly at a site other than the active site. This
binding leads to:
Section 3 Biochemistry
A. Increase in Km and V
B. Increase in V
C. Decrease in V
D. No change in V
and Km remains constant
max
and Km remains constant
max
max
remains constant
max
and K
m
115. Enzyme inhibition caused by a substance
resembling substrate molecule is:
A. Competitive inhibition
B. Non-competitive inhibition
C. Feedback inhibition
D. Allosteric inhibition
116. Haemolytic anaemia disease is caused by the
deciency of one of the enzymes of the pentose
phosphate pathway:
A. Glucose-6-phosphate dehydrogenase
B. Aldolase
C. Fructose 1,6-bisphosphatase
D. Phosphohexose isomerase
117. Sphingosine is produced in which of the following
cell organelles ?
A. Mitochondria
B. Ribosome
C. Nucleus
D. Endoplasmic reticulum
118. Out of following which one is responsible for
inhibition of the reaction of citric acid cycle?
A. Isocitrate α-ketoglutarate
B. Fumarate α-malate
C. Citrate α-cis-aconitate
D. Succinate α-fumarate
119. Ketosis occurs with which of the following
diseases:
A. Nephritis
B. Diabetes mellitus
C. Myocardial infarction
D. None of the above
120. Which of the following enzymes is elevated in
alcoholism?
A. Hepatitis
B. Serum glutamate pyruvate trasmittase
C. Acid Phosphatase
D. Glutamyl transpeptidase
121. Pyruvate dehydrogenase is a/an:
A. Isomerase B. Lyase
C. Ligase D. Oxidoreductase
122. The main source of reducing equivalents (NADPH)
for lipogenesis is:
A. Pentose phosphate pathway
B. Citric acid cycle
C. Glycolysis
D. Glycogenolysis
123. The rate limiting reaction in the lipogenic pathway
is:
A. Acetyl-CoA carboxylase step
B. Ketoacyl synthase step
C. Ketoacyl reductase step
D. Hydratase step
124. An enzyme was crystallized for the rst time by:
A. John Northrop B. Edward Buchner
C. J.B. Sumner D. None of these
125. Polyunsaturated fatty acids synthesis requires
which of the following enzyme systems?
A. Acyl transferase and hydratase
B. Desaturase and dehydrogenase
C. Ketoacyl-CoA reductase and phosphatases
D. Dihydroxyacetone phosphate
126. __________ is a biocatalyst that increases the rate
of the reaction without being changed.
A. Aluminium oxide B. Silicon dioxide
C. Enzyme D. Hydrogen peroxide
127. Phospholipase C attacks the ester bond liberating
1,2-diacylglycerol and a phosphoryl base at
position:
A. 1 B. 2
C. Both A and B D. 3
128. The class of enzymes which is responsible for
the catalysation of synthetic reactions where two
molecules are linked with each other and ATP
molecule is used is:
A. Reductases B. Lyases
C. Ligases D. Oxidases
129. In renal glycosuria __________ condition occurs.
A. Hyperglycaemia
B. Hyperglycaemia with glycosuria
C. Blood glucose level is normal with glycosuria
D. All of the above
130. In albinism which enzyme is decient?
A. Phenylalanine hydroxylase
B. Tyrosinase
C. p-Hydroxyphenylpyruvic acid oxidase
D. Tyrosine dehydrogenase
131. Enzymes have a 3-D shape due to which type of
protein structure?
A. Quaternary structure
B. Tertiary structure
C. Secondary structure
D. Primary structure
132. In non-competitive inhibition, quantity which
remains same as reaction proceeds is:
A. V
C. K0 D. V
B. K
max
m
0
133. The origin of all the carbon atoms of cholesterol
is:
A. Bicarbonate B. Acetyl-CoA
C. Succinyl-CoA D. All of these
134. For reduction, enzyme HMG-CoA reductase
requires cofactor:
A. NADPH B. NADP
C. NAD D. FAD
135. Which type of enzyme catalyses the reaction in
which dipeptide is converted into two separate
amino acids?
A. Decarboxylase B. Dehydrogenase
C. Hydrolase D. Oxidoreductase
136. Which of the following is required for the
attachment of phosphoryl groups to specic amino
acid residues?
A. Diphtheria toxin and cholera toxin
B. Dinitrogenase reductase
C. Protein phosphatases
D. Protein kinases
137. The principal sterol excreted in feces is:
A. Coprostanol B. Zymosterol
C. Lanosterol D. Desmosterol
138. Succinate is the substrate for succinate dehydrogenase that converts succinate to fumarate. In the
presence of reversible competitive inhibitor like
malonate in place of succinate, the enzymes
A. Km increases and V
B. both Km and V
C. both Km and V
max
max
D. Km decreases and V
remains the same
max
increases
decreases
remains the same
max
139. __________ is a number of substrate molecules
changed into product by one molecule of enzyme
active site per unit of time.
A. Turnover number B. Substrate number
C. Reaction number D. ES complex
140. When starch and amylase are mixed together with
iodine solution, the blue-black colour quickly
disappears. It happens because of:
A. Glucose B. Maltose
C. Sucrose D. All of these
141. An enzyme that requires a biological change in
order to become active is called:
A. Transferase B. Zymogen
C. Hydrogenase D. Trypsin
142. The enzyme decient in Sandhoff’s disease is:
A. α-Fucosidase
B. Hexosaminidase A and B
C. β-Galactosidase
D. β-Glucosidase
143. If glucose-1-phosphate formed by glycogenolysis
in muscles is oxidized to CO2 and H2O, the energy
yield will be:
A. 2 ATP equivalents
B. 3 ATP equivalents
C. 4 ATP equivalents
D. 8 ATP equivalents
Section 3 Biochemistry
421420
144. The isozyme CK-MB is specically increased in
the blood of patients who had:
A. Skeletal muscle disease
B. Recent myocardial infarction
C. Infective hepatitis
D. Myxoedema
145. Pancreatic zymogens are only activated when they
reach the:
A. Stomach B. Pancreas
C. Small intestine D. Large intestine
146. According to the rst law of thermodynamics:
A. Loss of energy occurs due to the heat generation
B. Those systems which are rich in energy are
intrinsically unstable in nature and will give
up energy along with time
C. Energy can be neither created nor destroyed
D. A and B only
147. Name of pathway in which synthesis of compounds
occur is:
A. Anabolic pathways
B. Catabolic pathways
C. Amphibolic pathway
D. None of the above
148. Lactate dehydrogenase is located in:
A. Lysosomes B. Mitochondria
C. Cytosol D. Microsomes
149. A molecule of phosphorylase kinase is made-up
of:
A. 4 subunits B. 8 subunits
C. 12 subunits D. 16 subunits
150. In citric acid cycle, NAD is reduced in:
A. One reaction B. Two reactions
C. Three reactions D. Four reactions
151. Koshland’s theory of enzyme action is known as:
Section 3 Biochemistry
A. Reduced fit theory
B. Lock and key theory
C. Induced fit theory
D. Enzyme–coenzyme theory
152. A coenzyme required in transamination reactions
is:
A. Coenzyme A B. Coenzyme Q
C. Biotin D. Pyridoxal phosphate
153. Which of the following cycles shows amphibolic
pathway?
A. Glyoxylate B. Citric acid cycle
C. Glycolysis D. Lipid metabolism
154. When the velocity of an enzymatic reaction equals
V
, substrate concentration is:
max
A. Half of Km B. Equal to Km
C. Twice the Km D. Far above the Km
155. The rate-determining step of Michaelis Menten
kinetics is:
A. The complex formation step
B. The complex dissociation step to produce a
product
C. The product formation step
D. Both A and C
156. Coenzymes combine with
A. Proenzymes B. Apoenzymes
C. Holoenzymes D. Antienzymes
157. Which of the following equation gives the
relationship between ∆G′ and Keq?
A. DG′ = –RT ln K
B. DG′ = ln K
eq
eq
C. DG′ = ∆G′ (–RT Keq)
D. DG = –RT ln K
eq
158. Which of the following is true about MichaelisMenten kinetics?
A. Km, the Michaelis constant, is defined as that
concentration of substrate at which enzyme is
working at maximum velocity
B. It describes single substrate enzymes
C. Km, the Michaelis constant is defined as the
dissociation constant of the enzyme–substrate
complex
D. It assumes covalent binding, occurs between
enzyme and substrate
159. Linear inhibition is sometimes called:
A. Complete inhibition
B. Incomplete inhibition
C. Partial inhibition
D. Mixed inhibition
160. The conversion of NAD+ to NADH is an example
of reduction because:
A. The pyridine ring loses electrons
B. The pyridine ring accepts electrons
C. The adenine ring loses electrons
D. The adenine ring gains electrons
161. What is reduction potential?
A. When a molecule loses an electron
B. An atom/molecule gains an electron
C. Reducing the power of an electron
D. Oxidation power of an electron
162. Who coined the word enzyme?
A. Wilhelm Kuhne B. Alfred Russel
C. Robert Koch D. Rosalind Franklin
163. In enzyme assays, all the following are kept
constant, except:
A. Substrate concentration
B. Enzyme concentration
C. pH D. Temperature
164. The types of inhibition patterns based on
Michaelis-Menten equation are:
A. Competitive B. Non-competitive
C. Uncompetitive D. All of these
165. Which of the following is/are serine proteases?
A. Chymotrypsin B. Trypsin
C. Elastase D. All of these
166. Non-protein part of an enzyme is called:
A. Coenzyme B. Cofactor
C. Substrate D. Activator
167. Which of the following acts as a storage form of
high energy phosphate?
A. Glucose-6-phosphate
B. Phosphoenolpyruvate
C. Phosphagens
D. Glycerol phosphate
168. Both acyl carrier protein (ACP) of fatty acid
synthetase and coenzyme (CoA):
A. Contain reactive phosphorylated groups
B. Contain thymidine
C. Contain phosphopantetheine reactive groups
D. Contain cystine reactive groups
169. The non-protein organic part of the enzyme is:
A. Cofactor B. Coenzyme
C. Apoenzyme D. Isoenzyme
170. An example of a gluconeogenic enzyme is:
A. Phosphofructokinase
B. Pyruvate kinase
C. Phosphoenol pyruvate carboxykinase
D. None of the above
171. A substrate for the enzyme aldolase is:
A. Galactose-6-phosphate
B. Isocitric acid
C. Glucose-1-phosphate
D. Fructose-1, 6-diphosphate
172. In enzymatic mechanism, substrate binds to
enzyme active site to produce:
A. Reactant B. Enzymes
C. Products D. ES complex
173. In humans, salivary amylase enzyme breaks down
starch. The optimum pH for this reaction is:
A. 6 B. 6.2
C. 6.4 D. 6.7
174. Urease is a:
A. Lyase B. Ligase
C. Isomerase D. Hydrolase
175. This catalyzes the formation of CoA derivatives
from fatty acid, CoA and ATP:
A. Acyl-CoA dehydrogenase
B. Enoyl hydrase
C. β-OH acyl-CoA dehydrogenase
D. Thiokinase
176. Regulation of some enzymes by covalent
modication involves the addition or removal of:
A. Acetate B. Sulphate
C. Phosphate D. Coenzyme
177. Which of these enzymes is related to molecular
biology?
A. DNA ligase B. DNA topoisomerase
C. Polymerase D. All of these
178. Pepsin is:
A. Exopeptidase B. Endopeptidase
C. Carboxy peptidase D. Amino peptidase
179. Enzymes are classied into ____________ types.
A. Two B. Three
C. Five D. Six
180. Lock and key theory of enzyme action was
proposed by:
A. Fischer B. Koshland
C. Kuhne D. Arrhenius
181. Enzyme activity can be blocked or retarded on
minute disturbance in:
A. Density B. Optimum pH
C. Temperature D. Concentration
182. SI unit for enzyme activity is:
A. Bel B. mho
C. Hertz D. Katal
183. The majority of the enzymes are inactive at:
A. At 25ºC B. At 15ºC
C. Between 30 and 40ºC D. Above 70ºC
184. The complex that forms when a substrate binds
to an enzyme, is called:
A. Enzyme-substrate complex
B. Enzyme complex
C. Substrate complex
D. Structural complex
185. Coenzyme is:
A. Often a vitamin
B. Always an inorganic compound
C. Always a protein
D. Often a metal
Section 3 Biochemistry
423422
186. Inactive enzymes which are not bound to their
cofactors are called:
A. Apoenzymes
B. Coenzymes
C. Enzyme inhibitors
D. Holoenzymes
188. Induced t theory for the formation of enzyme–
substrate complex was proposed by:
A. Koshland B. Charles Leibeg
C. Buchner D. Fischer
189. An important nding in hyperammonemia type II is:
A. Increased serum gluatmine level
B. Enlarged liver
187. Enzymes activity is regulated by:
A. pH
B. Concentration of the enzyme
C. Concentration of the substrate
D. All of the above
C. Mental retardation
D. Increased carbamoyl phosphate synthetase level
190. The nature of the enzyme is:
A. Protein B. Lipid
C. Carbohydrate D. None of these
ANSWER KEY
1. C 2. B 3. D 4. B 5. B 6. D 7. D 8. D 9. A 10. C 11. D 12. C 13. D 14. A
15. C 16. A 17. D 18. D 19. C 20. D 21. D 22. D 23. C 24. B 25. B 26. B 27. C 28. A
29. B 30. B 31. A 32. A 33. A 34. A 35. A 36. A 37. B 38. B 39. C 40. B 41. A 42. B
43. D 44. C 45. B 46. B 47. C 48. A 49. D 50. A 51. D 52. C 53. A 54. D 55. C 56. C
57. C 58. A 59. A 60. A 61. A 62. A 63. C 64. B 65. C 66. B 67. A 68. A 69. B 70. B
71. A 72. A 73. A 74. B 75. A 76. D 77. D 78. B 79. A 80. B 81. C 82. C 83. D 84. A
85. C 86. A 87. D 88. B 89. A 90. A 91. B 92. D 93. A 94. A 95. A 96. A 97. B 98. A
99. A 100. C 101. A 102. D 103. D 104. D 105. C 106. A 107. D 108. A 109. D 110. B 111. A 112. A
113. C 114. C 115. A 116. A 117. D 118. C 119. B 120. D 121. D 122. A 123. A 124. C 125. A 126. C
127. D 128. C 129. C 130. C 131. B 132. B 133. B 134. A 135. C 136. D 137. A 138. A 139. A 140. B
141. B 142. B 143. B 144. B 145. C 146. C 147. A 148. C 149. D 150. C 151. C 152. D 153. B 154. D
155. B 156. B 157. A 158. B 159. A 160. B 161. B 162. A 163. B 164. D 165. D 166. B 167. C 168. C
169. B 170. C 171. D 172. C 173. D 174. D 175. D 176. C 177. D 178. B 179. D 180. A 181. B 182. D
183. D 184. A 185. A 186. A 187. B 188. A 189. C 190. A
8. Nucleic Acids
Discovered by Friedrich Miescher in 1869 from pus cells
called nuclein. Because it has acidic properties, hence it
is called nucleic acid.
The hereditary information is carried out by genes
(within the chromosomes).
Chromosomes are made-up of histone protein and
nucleic acids.
Nucleic acids are polynucleotides.
Structure of nucleic acids divided into four different
levels:
a. Primary structure
b. Secondary structure
c. Tertiary structure
d. Quaternary structure
DNA stores the genetic information of an organism
Section 3 Biochemistry
and transmits that information from one generation to
another.
RNA translates the genetic information contained in
DNA into proteins needed for all cellular function.
A nucleotide is composed of:
Nitrogen-containing bases (amines).
Sugars (monosaccharides).
Phosphate.
The DNA model is proposed by Watson and Crick in
1953.
Two strands of polynucleotide form a double helix
structure like a spiral.
Replication
Component Function
Helicase Unwinds the DNA double helix
Primase Synthesizes primers
Clamp protein Threads leading strand
DNA polymerase Joins assembled nucleotides
Ligase Joins Okazaki fragments in lagging
strand
Genetic codon
RNA has β-D-ribose in it as the sugar moiety.
The heterocyclic bases present in RNA are adenine (A),
guanine (G), cytosine (C) and uracil (U). In RNA, the
fourth base is different from that of a DNA.
1. Messenger RNA (mRNA)
2. Ribosomal RNA (rRNA)
3. Transfer RNA (tRNA)
Ribosomes are the sites of protein synthesis; they are made-up
of ribosomal DNA (65%) and proteins (35%); they are divided
into two subunits, one large and one small. Messenger RNA
carries the genetic code to the ribosomes; it is made-up of
strands of RNA that are complementary to the DNA of the
gene for the protein to be synthesized. The genetic code
from messenger RNA is translated by transfer RNA, which
transports specific amino acids to the ribosome for protein
production. One or more distinct tRNAs recognize each amino
acid. The tertiary structure of tRNA is L-shaped, with one end
attaching to the amino acid and the other to the mRNA via a
three-base complementary sequence.
Deoxyribonucleic Acid (DNA)
DNA has a pentose sugar, phosphoric acid and some
cyclic bases containing nitrogen.
The sugar moiety present in DNA molecules is β-D-2-
deoxyribose.
The cyclic nitrogenous bases are: Adenine (A),
guanine (G), cytosine (C) and thymine (T).
DNA has a double-stranded helical structure in which
both the strands are complementary to each other.
Ribonucleic Acid (RNA)
The RNA molecule is also composed of phosphoric acid,
a pentose sugar and some cyclic bases containing nitrogen.
Parameters Purines Pyrimidines
Introduction Purine is a
heterocyclic
aromatic
chemical
molecule
made-up of a
pyrimidine ring
and an imidazole
ring fused
together
Function RNA and DNA
synthesis,
protein and
starch synthesis,
enzyme
Pyrimidine is a
heterocyclic aromatic
chemical molecule
with two nitrogen
atoms in positions
1 and 3 of its sixmembered ring,
similarly to benzene
and pyridine. It
has two additional
diazine isomers
RNA and DNA
synthesis, protein
and starch synthesis,
enzyme regulation,
and cell signalling
regulation, and
cell signalling
Nucleobases Adenine and
guanine
Structure An imidazole
ring fused to a
pyrimidine ring
There are two
Cytosine, thymine,
uracil
Contains one
carbon–nitrogen ring
and two nitrogen
atoms
carbon–nitrogen
rings and four
nitrogen atoms
in this compound
There is one
carbon–nitrogen
ring and two
nitrogen atoms in
this compound
Contd...
Section 3 Biochemistry
425424
Parameters Purines Pyrimidines
Melting point 214°C, 487 K,
20–22°C
417°F
Type of
compound
Molecular
Heterocyclic
aromatic organic
compound
C
5H4N4
Heterocyclic
aromatic organic
compound
C4H4N
2
formula
Molar mass 120.11 g mol
−1
80.088 g mol
–1
Classification of Mutations
Substitution: One of the other three bases is substituted
for base
Deletion: Block of one or more DNA pairs is lost
Insertion: Block of one or more DNA pairs is added
Inversion: 180° rotation of piece of DNA
Reciprocal translocation: Parts of nonhomologous
chromosomes change places
Chromosomal rearrangements: Affect many genes at
one time
Nonsense mutation: Changes an amino acid to a STOP
codon, resulting in premature termination of translation.
Missense mutation: Changes an amino acid to another
amino acid. This may or may not affect protein function.
“Silent” mutation: Although it does not modify an
amino acid, it can nonetheless have phenotypic effects in
some situations, such as speeding up or slowing down
protein synthesis or changing splicing.
Frameshift mutation: Deletion or insertion of a number
of bases that is not a multiple of 3.
Hereditary Disorders
Hereditary Elliptocytosis
Presents a diverse group of haemolytic anaemias.
Characterized by the presence of numerous ovals, elliptical,
or elongated erythrocytes in the peripheral blood.
The disorder is associated with defective erythrocyte
membrane skeletal proteins in horizontal interactions.
HE has been divided into three major clinical groups:
a. Common type
b. Spherocytic type
c. Stomatocytic type.
Spherocytosis
Generation of abnormal-shaped red blood cells (sphere
shaped instead of the concave disk-shaped)
Fragile and abnormal red blood cells
Symptoms and signs of spherocytosis include:
anaemia, paleness (pallor), jaundice, enlarged spleen
(splenomegaly), gallbladder problems.
Diabetes Insipidus
Rare disease
Causes frequent urination
May causes bedwetting
Chances of dehydration are high.
Types of Diabetes Insipidus
Central DI
Nephrogenic DI
Dipsogenic DI
Gestational DI.
MULTIPLE CHOICE QUESTIONS
1. According to Chargaff’s rule a typical DNA
contains:
A. A = G B. A = C
C. A = U D. A + G = T + C
2. As per the Watson-Crick model of DNA which of
the following statements is correct:
A. A purine of one strand of DNA is always linked
with a purine in the other strand of DNA by
hydrogen bonds
B. A–T pairing has three hydrogen bonds
C. G–C pairing has two hydrogen bonds
D. Nitrogenous bases occupy the interior space of
the helix
3. The double helical structure of B-form DNA is
stabilized:
Section 3 Biochemistry
A. By covalent bonds formed between the 3’-end
of one strand and the 5’-end of the other.
B. By hydrogen bond formed between the
phosphate groups of two strands
C. By hydrogen bonds formed between the ribose
of each strand
D. By nonspecific base-stacking interaction
between two adjacent bases in the same strand
4. B-form DNA in vivo is a ________-handed helix,
_____ Å in diameter, with a rise of ____ Å per base
pair.
A. Left; 20; 3.9 B. Right; 18; 3.4
C. Right; 20; 3.4 D. Right; 23; 2.6
5. Transfer RNA transfers:
A. Information from DNA to ribosomes
B. Information from mRNA to cytosol
C. Amino acids from cytosol to ribosomes
D. Proteins from ribosomes to cytosol
6. Some restriction enzymes generate sticky ends.
This means that:
A. They cut at high GC content region, by doing
this, it leaves ends those able to form more
hydrogen bonds than ends of rich AT content
B. Make a staggering double-strand cut by doing
this leaves ends with a smaller number of
nucleotides of single-stranded DNA protruding
C. Cut both DNA strands at the same base pair
D. All of the above
7. GMP acts as an allosteric inhibitor for all, except
A. PRPP synthetase
B. Glutamyl amido synthetase
C. Adenyl succinate synthetase
D. None of the above
8. Peptide bond is:
A. Rigid with partial double bond character
B. Planar, covalent
C. Covalent
D. All of the above
9. Choose one correct statement about promoters in
E. coli.
A. RNA polymerase holoenzyme recognizes
promoters that have the same sequence
B. All promoters vary in their sequence
C. Lots of promoters are same and match a
consensus sequence, which has the highest
affinity for RNA polymerase holoenzyme
D. Both A and C
10. Which of the following is not a factor responsible
for the denaturation of proteins?
A. pH change B. Organic solvents
C. Heat D. Charge
11. β-Aminoisobutyrate is formed from the catabolism of:
A. Cytosine B. Uracil
C. Thymine D. Xanthine
12. Inheritance of primary gout is:
A. Autosomal recessive
B. Autosomal dominant
C. X-linked recessive
D. X-linked dominant
13. An alternate substrate for orotate phosphoribosyl
transferase is:
A. Allopurinol B. Xanthine
C. Hypoxanthine D. Adenine
14. Extranuclear DNA is present in:
A. Ribosomes
B. Endoplasmic reticulum
C. Lysosomes D. Mitochondria
15. Which of the following is required in protein
synthesis?
A. ATP B. GDP
C. GTP D. AMP
16. Translation results in a product known as:
A. Protein B. tRNA
C. mRNA D. rRNA
17. When DNA is chemically synthesised:
A. Nucleotide which is initially attached to the
silica gel support that will become the 3’-end
of the final product
B. Formation of the phosphodiester bond catalyses
by dimethoxy trityl group catalyses
C. Only 8–10 nucleotides can be synthesized
D. None of the above
18. After formation of replication fork:
A. Both the new strands are synthesized
discontinuously
B. One strand is synthesized continuously and the
other discontinuously
C. Both the new strands are synthesized
continuously
D. RNA primer is required only for the synthesis
of one new strand
19. Out of that does not occur when double-stranded
DNA is heated at neutral pH is:
A. Increase in the absorption of ultraviolet light
B. The covalent bond (N-glycosidic bond) is
formed between the base and the pentose
breaks
C. The hydrogen bonds formed between A and T
break point
D. Both B and C
20. Source(s) of nitrogen atoms for de novo synthesis
of purine nucleotides is/are:
A. Aspartate and alanine
B. Alanine and glycine
C. Aspartate, glutamine and glycine
D. Aspartate, glutamate and glycine
21. Ribozymes are:
A. Enzymes present in ribosomes
B. Enzymes that combine the ribosomal subunits
C. Enzymes that dissociate
D. Enzymes made-up of RNA
22. Out of the following which statement is/are
correct:
A. Exonucleases degrade DNA at a free end
B. Endonucleases degrade circular but not linear
DNA molecules
C. Many DNA polymerases have a proofreading
5’ → 3’ exonuclease
D. E. coli DNA polymerase I is unusual in that, it
possesses only a 5’ → 3’ exonucleolytic activity.
23. eIF-1A and eIF-3 are required:
A. For binding of amino acyl tRNA to 40S
ribosomal subunit
B. For binding of mRNA to 40S ribosomal subunit
C. For binding of 60S subunit to 40S subunit
D. To prevent binding of 60S subunit to 40S
subunit
24. By incubating a mixture containing ………………
articial mRNA polyadenylic acid can be prepared
in the laboratory.
A. DNA, ATP, and DNA polymerase
B. GTP and an RNA polymerase
C. UTP and polynucleotide phosphorylase
D. ADP and polynucleotide phosphorylase
Section 3 Biochemistry
427426
25. Nuclear DNA is present in combination with:
A. Histones B. Non-histones
C. Both A and B D. None of these
26. DNA supercoiling:
A. Results in compaction of the DNA structure
B. Is induced by the process of DNA replication
C. Is induced by the process of RNA synthesis
(transcription)
D. All of the above
27. Tri-peptide consists of:
A. 3 amino acids and 3 peptide bonds
B. 2 amino acids and 3 peptide bonds
C. 3 amino acids and 2 peptide bonds
D. 3 amino acids and 4 peptide bonds
28. Aminoacyl-tRNA synthetase that attaches an
amino acid to a tRNA:
A. Always identify a specific tRNA
B. Catalyzes the reaction in which an ester bond
is formed
C. Linked a specific amino acid to available tRNA
D. Linked amino acid at the 5’-end of the tRNA
29. The correct sequence of the reactions of catabolism
of adenosine to uric acid is:
A. Adenosine→Hypoxanthine→Xanthine→Uric
acid
B. Adenosine→Xanthine→Inosine→Uric acid
C. Adenosine→Inosine→Hypoxanthine→
Xanthine→Uric acid
D. Adenosine→ Xanthine→Inosine→
Hypoxanthine→Uric acid
30. In living cells nucleotides serve as:
A. Precursors for nucleic acid synthesis
B. Enzyme cofactors
C. Carriers of metabolic energy
D. All of the above
31. Choose incorrect statements about thioredoxin
reductase.
A. NADH act as a coenzyme
B. Substrates names are ADP, GDP, CDP and UDP
C. Activated by ATP
D. Inhibited by dADP
32. RNA polymerase:
A. It performs the separation of DNA strands from
a long region of DNA that contains thousands
of base pairs, then copies one of them
B. It has a lambda subunit, which performs a
proofreading function
C. Can synthesize RNA chains de novo (without a
primer).
D. All of the above
33. Topoisomerases can:
A. Increase the number of nucleotide base pairs in
Section 3 Biochemistry
a DNA
B. Decrease the number of nucleotides base pair
in a DNA
C. Change the linking number (Lk) of a DNA
D. Change D isomers of nucleotides into L isomers
34. Which of the following is not the classied form
of conjugated proteins?
A. Lipoproteins B. Glycoproteins
C. Metalloproteins D. Complete proteins
35. Peptidyl transferase activity of 50S ribosomal
subunits is inhibited by:
A. Rifampicin B. Cycloheximide
C. Chloramphenicol D. Erythromycin
36. The fundamental repeating unit of organization
in a eukaryotic chromosome is:
A. The centrosome B. The nucleosome
C. The lysosome D. The microsome
37. The process of sorting and transporting newly
synthesized proteins to the correct destination in
a cell is called:
A. Protein sorting B. Protein targeting
C. Protein trafficking D. All of these
38. For the synthesis of TMP from the dump, a
coenzyme is required which is:
A. N10-Formyl tetrahydrofolate
B. N5-Methyl tetrahydrofolate
C. N5, N10-Methylene tetrahydrofolate
D. N5-Formimino tetrahydrofolate
39. A tripeptide has:
A. 3 amino acids and 1 peptide bond
B. 3 amino acids and 2 peptide bonds
C. 3 amino acids and 3 peptide bonds
D. 3 amino acids and 4 peptide bonds
40. Which of the following deoxyoligonucleotides
will hybridize with a DNA containing the
sequence (5’)AGACTGGTC(3’)?
A. (5’)TCTGACCAG(3’)
B. (5’)GAGTCAACT(3’)
C. (5’)GACCAGTCT(3’)
D. (5’)TCTGGATCT(3’)
41. Orotic aciduria can be controlled by:
A. Oral administration of orotic acid
B. Decreasing the dietary intake of orotic acid
C. Decreasing the dietary intake of pyrimidines
D. Oral administration of uridine
42. Amplication of dihydrofolate reductase gene may
be brought about by:
A. High amount of folic acid
B. Deficiency of folic acid
C. Low amount of thymidylate
D. Amethopterin
43. Choose incorrect statements about uric acid,
except:
A. It is a catabolite of pyrimidines
B. It is excreted by the kidney
C. It is undissociated at pH above 7.3
D. It is undissociated at pH above 5.8