(5)
Bio-Chemistry(Ph.D.)
1.
Special structures called telomeres are needed in
eukaryotic cells but not in bacteria because eukaryotic cells contain
A)
Linear chromosomes B)
More than one chromosome
C) A nucleus D)
Circular chromosomes
2.
Albinism is a
A)
Hereditary disease B)
Deficiency disease C) Sex-linked
disease D)
Degenerative disease
3.
The regions of chromatin which usually undergo
transcription are:
A)
Nucleosomes B)
Heterochromatin
C) Euchromatin D)
Both euchromatin and heterochromatin
4.
In gel filtration chromatography , the separation of
proteins is based on-
A)
Size and charge B)
Only charge
C) Size and shape D)
size and
specific affinity
5.
If a cell has one chromosome in excess of the normal
number of chromosomes present in the nucleus ,it is referred to as –
A)
Polyploid B) Aneuploid
C) Tetraploid D)
Haploid
6.
If total amount of Guanine and cytosine is 52% in a
double stranded DNA, the amount of adenine in this DNA would be-
A)
52% B)
24% C)
26% D)
48%
7.
You want to purify a recombinant protein by affinity
chromatography using a Ni column.
You should tag the protein with-
A)
Histidine B)
Biotin
C)
Glutathione-S-transferase (GST) D) Proline
8.
The first trial of gene therapy was for this disorder
A)
Thalasemia
B) Cancer
C)
Severe combined immunodeficiency disease
D)
Hemophilia
9.
What is antisense technology?
A)
RNA polymerase producing DNA
B)
Synthesis of cDNA from mRNA
C)
Synthesis of lagging DNA strand
D) Synthesis of
complementary RNA sequence to stop the expression of a specific gene
10. A
gene pair hides the effect of another. The phenomenon is:
A)
Epistasis B)
Dominance C) Mutation D) None of these
11. Extracellular
materials are taken inside the cell by invagination of a segment of plasma
membrane by:
A)
Exocytosis B) Endocytosis C) Active transport D) Osmosis
12. Following
are the steps in DNA fingerprinting:-
i)
Hybridisation with probe
ii)
Isolation of DNA
iii)
Digestion of DNA with restriction endonucleases iv) Detection by autoradiography
v) Separation
of DNA fragments by electrophoresis vi)
transferring the fragments to synthetic membrane
Which is the
correct order of the steps:- A) i,ii,iii,iv,v,vi B) v,vi,i,iii,ii,iv
C)
ii,iii,v,vi,i,iv D) ii,iii,v,vi,i,iv
13. Components
of the respiratory chain are arranged in order of
A)
Increasing redox potential B)
Decreasing redox potential
C) Equivalent redox potential D)
In any order of redox potential
14. The
Noble prize for chemistry in 2015 is given to , Modrich and Sarkar for thei
work on-
A)
Signal hypothesis
B)
Malarial drugs
C) DNA repair D)
Telomeres
15. The
anti cancer drug methotrexate is a:
A)
Purine analog B)
Pyrimidine analog
C) Folic acid analog D)
Inhibits RNA polymerase
16. An
alpha-helical conformation of a globular protein in solution is best determined
by which of the following?
A)
Ultraviolet-visible absorbance spectroscopy
B)
Fluorescence spectroscopy
C)
Electron microscopy
D) Circular dichroism
17. Acetyl
CoA, the cytoplasmic substrate for fatty acid synthesis, is formed in
mitochondria. The inner mitochondrial membrane is impermeable to acetyl CoA.
Which of the following compounds isthe form in which the carbon of acetyl CoA
is transported to the cytoplasm?
A)
Malate B)
Acetate C)
Pyruvate D)
Citrate
(2)
18. Which
of the following is NOT characteristic of a eukaryotic enhancer element?
A) Its activity is
independent of its orientation (i.e., the sequence can be inverted without
effect)
B)
Its activity is dependent on its distance from the
start site of transcription
C)
It increases the level of transcription of genes under
its control
D)
It may be found as far as 1 to 2 kilobases from the
promoter
19. Choose
the appropriate statement regarding Carbamoyl phosphate synthetase I and CPS II
A)
Both use ammonia as a substrate
B) CPS I uses ammonia and
CPS II uses glutamine as a source of nitrogen
C)
CPS I is involved in pyrimidine biosynthesis and CPS II
in urea cycle
D)
Both are involved in urea cycle
20. Which
statement is not true about transition state analogs-
A) It fits loosely in
active site as compared to the substrate
B)
It is a potent inhibitor of the enzyme
C)
It can be used as a hapten to produce catalytic
antibodies
D)
It mimics the reaction intermediate
21. A
PCR efficiency of ‘2’ means
A)
100% efficiency / initial target copies are doubled by
the end of the reaction
B)
95% efficiency / each target copy is doubled every
cycle
C) 100% efficiency / each
target copy is doubled every cycle
D)
95% efficiency / initial target copies are doubled by
the end of the reaction
22. Which
of the following is an advantage of nested PCR (nPCR)?
A)
Provides a quantitative assessment of initial starting
copy number
B)
Second round PCR products can be a source of laboratory
contamination
C)
Is less time consuming than single round conventional
PCR
D) Typically has high
sensitivity and specificity
23. Assume
that you have a cell that is able to complete glycolysis, the citric acid
cycle, and the steps of oxidative phosphorylation involving the electron
transport chain. However, the ATP synthase in this cell allows passage of H+
ions but does not produce ATP. When grown in aerobic conditions, you expect
this cell to generate
A)
The same amount of ATP as a cell that was fermenting.
B) A little more ATP than
a cell that was fermenting.
C)
A little less ATP than a cell that was fermenting.
D)
About the same amount of ATP as a cell that was
respiring normally under aerobic conditions
24. In
vitro experiments using a mutant DNA polymerase led to an increase in error
rate from 10-6 to 10-3. Which
activity is defective in mutant DNA polymerase.
A)
5’-3’ polymerase
B)
5’-3’ exonuclease
C) 3’-5’ exonuclease D)
3’-5’ polymerase
(3)
25. A
microfibril of cellulose is composed of about 80 molecules that lie parallel to
each other and close together. What type of bond holds the parallel fibers
together?
A)
Vanderwaal forces B)
Hydrophobic interactions
C) Ionic interactions D)
Hydrogen bonds
26. The
initial product of photosynthestic CO2 fixation in C3 plants is
A)
Phosphoenol pyruvate B)
3-
phosphoglycerate
C) Glyceraldehyde-3-phosphate D) Dihydroxyacetone phosphate
27. Presence
of SNARE proteins has been reported in the membrane of all the following cell
organelles except
A)
Endoplasmic reticulum B)
Golgi complex
C) Mitochondria D)
Early endosome
28. Membrane
carrier proteins differ from membrane channel proteins by which of the
following characteristics:-
A)
Carrier proteins do not bind to the transported
material while channel proteins do
B)
Carrier proteins are synthesised by free cytoplasmic
ribosomes while channel proteins are synthesised on endoplasmic reticulum bound
ribosomes
C)
Carrier proteins transport molecules down their
electrochemical gradient while channel proteins transport molecules against the
electrochemical gradient
D) Carrier proteins can
mediate active transport while channel proteins cannot
29. A
mutation deleting an upstream activating sequence for a single gene would be
expected to be
A)
cis-dominant B)
Trans-dominant
C) Silent D)
Reversible
30. Glycogen
phosphorylase is converted to its active form ‘a’ from its inactive form ‘b’
by-
A)
Proteolytic cleavage of a peptide fragment from
N-terminus
B)
Reversible dimerisation of phosphorylase b triggered by
Ca2+ ions
C)
Interaction of ATP on the allostearic site of the
enzyme
D) Phosphorylation of a
specific Serine residue on each subunit by ATP
31. The
length of an α-helix composed of 36 amino acid residues is
A)
10 Ã… B) 54 Ã… C)
27 Ã… D)
360 Ã…
32. Kwashiorkor
disease is caused by deficiency of the following-
A)
Total calorie intake B)
Proteins
C) Unsaturated fatty acids D)
Carbohydrates
33. In
vertebrate genes, transcription regulating regions that contain CpG islands are
inactivated by which modification
A)
Acetylation B)
Farnesylation C) Phosphorylation D) Methylation
(4)
34. Eukaryotic
cells with DNA damage does not undergo cell cycle until defective DNA is
repaired. This phenomenon is called
A)
Check point control B)
Transcriptional control
C) Damage control D)
Anticyclin control
35. A
typical curve for an enzyme catalysed reaction is given below. Y- axis depicts
the rate of reaction, then X- axis
will be represented by -
A) Substrate
concentration or pH
B)
Substrate concentration or temperature
C)
Substrate concentration or enzyme concentration
D)
pH or Temperature
36. Choose
the incorrect statement about the dielectric constant.
A)
It is unity in vaccum.
B)
It is a measure of the ability of a solvent to keep
opposite charges apart.
C)
Non polar substances have a small dielectric constant.
D) Water has the lowest
dielectric constant.
37. The
primary action of a steroid hormone is at the level of-
A)
mRNA degradation
B)
Transcription C) RNA export from the nucleus D) Pre mRNA splicing
38. Which
is the most useful experiment that can be done by using a DNA microarray?
A) Comparing RNA produced
under two physiological conditions to
understand gene expression
B)
Predicting the presence of specific metabolites in a
cell
C)
Evaluating the linkage relationship of two genes
D)
Comparing newly synthesized nuclear RNA with
cytoplasmic RNA to locate introns
39. Which
of the following statement is true for both Diabetes and starvation?
A)
Blood glucose is elevated
B)
The tissues have higher expression of glucose transporters
C) Brain switches to
ketone bodies for energy production
D)
It is accompanied by high levels of insulin
(5)
40. Pick
the odd pair out
A)
ErbB- epidermal growth factor receptor
B)
TrkA- nerve growth factor receptor
C)
Ras- guanine nucleotide binding factor with GTPase
activity
D) Fos- platelet derived
growth factor
41. Which
of the following is not true for thiamine –
A)
Act as a coenzyme for pyruvate dehydrogenase
B) Milk is a good
source
C)
Deficiency causes beri-beri
D)
Deficiency can be assessed by transketolase activity
42. Which
of the following is not true for liposomes-
A) They can be formed by
sonicating the suspension of any lipid dissolved in aqueous medium
B)
These are composed of an aqueous compartment enclosed
by a lipid layer
C)
These can be used for drug delivery to the target
tissues
D)
Molecules can be trapped in the aqueous compartment of
lipid vesicles
43. Given
below is the energy profile of a given reaction. What will be the energy of
A)
3 B) 4 C)
2 D)
1
44. In
density gradient centrifugation , which of the following DNA molecules will
travel the farthest down the tube-
A)
13C-15N duplex B)
15N-15N duplex
C) 15N-14N
duplex D)
14N-14N duplex
(6)
45. Which
of the following statements is true for phospholipid molecules?
i) The
polar end of phospholipids would contain carbon and phosphorous and oxygen. ii) The non-polar end of
phospholipids would contain almost exclusively carbon and hydrogen.
iii)
The polar end of
phospholipids would form hydrogen bonds with water.
iv)
The non-polar end of
phospholipids associate with the cytoplasm of the cell.
A) All of these B) i, ii C)
ii, iii D) i, ii, iii
46. The
main difference between normal and transformed cells are-
A)
Shorter cell cycle duration
B)
Increased apoptosis
C) Immortality and
contact inhibition
D)
Hyperfunction of tumor suppressor genes
47. Which
of the following statements about retrotransposons is correct?
A)
They contain genes for ribosomal proteins.
B) They transpose via RNA
intermediate.
C)
They possess a gene for RNA dependent RNA polymerase.
D)
They are found only in bacteria.
48. Lipid
rafts present in the membrane have different composition then rest of the
membrane. On isolation it was found that rafts have cholesterol to sphingolipid
ratio of 2:1. Estimated size of raft is 30nm. Surface area of cholesterol is
30A02 and that of sphingolipids is 60A02. How many molecules
of cholesterol and sphingolipid are present in the lipid raft.
A) 30 Cholesterol: 15 sphingolipids
B) 60 Cholesterol: 30
sphingolipids
C) 50 Cholesterol: 25 sphingolipids D) 15 Cholesterol: 30 sphingolipids
49. All
of the following statements apply to transport of macromolecules into and out
of the nucleus except
A)
The protein , Importin differentiates between its cargo and other proteins
B)
The energy for nuclear transport is provided by the
small Ras family GTPase, Ran
C)
Transport occurs
through large,
proteinaceous structures called nuclear pore complexes
D) A signal peptide
containing branched chain amino acids is present on N terminus of nuclear
proteins
50. What
molecule is used to signal low glucose levels to the Lac operon regulatory
system?
A) Cyclic AMP B) Calcium C) Lactose D) Pyruvate
x-x-x
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