DBT BET Previous Year Question Paper: 2012-2013 with Answer key: Part 4 (Question 101 – 150)


Telomer-structure

Three-dimensional structure of a telomere G-quadruplex (source wikipeida)

Biotechnology Eligibility Test (BET) for DBT JRF Award (2012-13)
Previous Year Question Papers with Answer Key, Explanations & References
Government of India, Ministry of Science & Technology
Department of Biotechnology, New Delhi
PART: B Set 4 (Questions 101– 150)


101. Telomeres consists of simple sequence repeats of

a. CATT rich strands that interact with protein
b. GCCT rich strands that interact with protein
c. CTTT rich strands that interact with protein
d. TTAGGG rich strands that interact with protein

Ans. (a)

Telomere is the sequence occurs at the end of chromosome. Telomere helps to maintain the integrity of chromosome by preventing the end to end fusion of different chromosome and deterioration of chromosomes by nucleases. In vertebrates telomere consists of TTAGGG sequence repeats (~2500 repeats).

102. True activators of transcription are transcription factors that binds to

a. Other proteins to enhance transcription
b. Promoters
c. Enhancers
d. Promoters and enhancers

Ans. (c)

Enhancers are cis acting transcription factor binding sites of DNA (50 – 1500 bp long) of specific genes

103. Position effect variegation describes

a. Phenotypically identical cells with different genetic elements
b. Phenotypically identical cells with similar genetic elements
c. Genetically identical cell with different phenotypes
d. Genetically identical cells with identical phenotype

Ans. (c)

Position effect: variation in the expression of genes when its position in the chromosome is changed particularly happens with translocation.

104. The U2 snRNA base pairs with

a. A sequence spanning the exon intron splicing site
b. The 3’ splice site of the intron
c. A sequence spanning the intron exon splicing site
d. The branched sequence in the intron

Ans. (d)

The U2 snRNA (U2 spliceosomal RNA) is a component of spliceosome involved in the splicing of pre mRNA

105. Isoelectric point of lysozyme is 9.2. When the enzyme solution at this pH in water was titrated with HCl to give a pH of 5, it was observed that six ionized glutamic acid side chains got protonated. The net charge on the enzyme at pH 6 would therefore be

a. +5
b. +6
c. -5
d. -6

 

Ans. (b)

Telomere caps

Human chromosomes (grey) capped by telomeres (white) (source wikipedia)

106. KCN is considered to be one of the potent poisons. You are doing an animal (mouse) experiment to test a new KCN sample synthesized by a chemist. The experiment is intravenous injection of KCN and checking the death of mouse. The sample was tested by many researchers and found to be pure and as potent as it should be. Although your experimental procedure were correct you failed to obtain desired results due to which one of the following

a. KCN resistant mice were used
b. Dose of KCN is much below the LD50 dose needed to kill the nice
c. KCN is being degraded in mice
d. KCN is immediately filtered by kidney

Ans. (b)

107. 6M Guanidium hydrochloride is known to denature a number of proteins. Such a high concentration is able to break down the covalent forces sustaining the structure of proteins by affecting:

a. Electrostatic interaction only
b. Electrostatic and hydrophobic interaction
c. Intra-peptidyl hydrogen bonding only
d. Electrostatic, hydrophobic, and hydrogen bonding interactions

Ans. (d)

108. Which of the following amino acid is critical in the folding of proteins due to the slow isomerization of the peptide bond preceding this amino acid depending upon the solvent environment?

a. Tryptophan
b. Leucin
c. Proline
d. Histidine

Ans. (c)

Proline is an iminoacid. Proline is the only amino acid with a secondary amine. Furthermore, it is unique in that the alpha-amino group is attached directly to the side chain, making the alpha carbon a direct substituent of the side chain.

109. In peptides the values of dihedral angle phi is based on rotation around

a. N – Cα bond
b. Cα – C’ bond
c. C’ – N bond
d. N – H bond

Ans. (a)

Psi bond: between Cα – C’ bond
Phi bond: N – Cα bond

110. A ribonuclease stock solution at pH 3.0 in 10 mM glycine HCl buffer is diluted 20 fold with the buffer and resulting absorbance of solution is taken in a quartz cuvette of path length 1 cm was 0.38 at its wavelength maximum. If the extinction coefficient of protein is 0.74 ml/mg.cm, the concentration of the stock protein solution would be

a. 5 mg/ml
b. 10mg.ml
c. 20mg/ml
d. 50 mg/ml

Ans. (b)

111. Which of the following techniques cannot be used to determine the molecular weight of a protein?

a. UV absorption
b. Viscosity
c. Light scattering
d. Sedimentation equilibrium

Ans. (a)

UB absorption is used to determine the concentration of protein in a sample. Proteins absorb UV light at 280 nm. Among the 20 amono acids in the protein, the UV light is only absorbed by tyrosine and tryptophan.

112. β-lactoglobulin which is a monomer at neutral pH is known to tetramerise at acidic pH of 2. Which one of the following technique could be effectively employed to demonstrate the formation of a tetramer?

a. Native gel electrophoresis
b. Anion exchange chromatography
c. SDS polyacrylamide gel electrophoresis
d. Reverse phase chromatography

Ans. (a)

113. If two heterozygous individuals suffering from an autosomal dominant disorder marry, what is the occurrence risk for this disorder in their offspring?

a. 100%
b. 75%
c. 50%
d. 25%

Ans. (b)

The progenies will segregate as 3:1 just as the typical Mendelian monohybrid cross ratio. Since the disease is autosomal and dominant, among the four possibilities, three will be diseased. The homozygous recessive individual will be devoid of the disease

114. A man who is affected with hemophilia A marries a woman who is a carrier of this disorder. What proportion among the following of this couple’s daughters will be affected and what proportion of the daughters will be carriers?

a. 0.75; 0.25
b. 0.25; 0.75
c. 0; 1
d. 0.5; 0.5

Ans. (a)

115. Which one of the following is an incorrect association?

a. Lysosome: synthesizes molecules from extracellular protein degradation
b. Mitochondria: cellular respiration
c. Endoplasmic reticulum: synthesize proteins and send them into Golgi apparatus
d. Polysomes: make large quantities of a particular protein

Ans. (a)

116. Which of the following statements about heritability (H2) is true

a. It is a measure of level of gene linkage
b. It is a measure of inbreeding
c. It is a measure of heterozygotes in a population
d. It is a measure of proportion of variation which is contributed by genetic factors

Ans. (d)

117. A threshold trait is one which is

a. Expressed on a continuous scale
b. Present in a few discrete classes but is influenced by environmental factors
c. Caused by only a single gene, with no environmental influence
d. Associated with superior survival of the heterozygote

Ans. (b)

118. Which of the following describes a type of polymorphism that occurs within the gene that causes Huntington’s disease?

a. Short tandem repeat polymorphism
b. Balanced polymorphism
c. Restriction fragment length polymorphism
d. Frame-shift mutatio

Ans. (a)

119. 5- bromouracil induces mutations because it

a. Replaces a T and binds to G rather than A
b. Replaces a G and binds to A rather than C
c. Changes the binding affinity of G
d. Changes the binding affinity of T

Ans. (a)

120. A homeotic mutation is one which

a. Is present only in one form in an individual
b. Results in developmental block of any tissue-specific gene expression
c. Substitutes one body part for another during development
d. Results from transposon mediated mutagenesis

Ans. (c)

121. Cystic fibrosis is a recessive condition that affects about 1 in 2500 babies in the Caucasian population. The frequency of heterozygotes of carriers of cystic fibrosis is

a. 1 in 12500
b. 1 in 25
c. 1 in 625
d. 1 in 125

Ans. (b)

122. Which of the following would cause deviation from the Hardy-Weinberg equilibrium?

a. Small population size
b. Random mating
c. Lack of selection pressure
d. No mutation

Ans. (a)

123. A woman who is a heterozygous carrier of an X lined recessive disease gene mates with a phenotypically normal male. The disease gene has a penetrance of 80%. On an average what proportion among the following of this couple’s sons will be affected with the disorder?

a. 0.8
b. 0.4
c. 0.2
d. 0.5

Ans. (b)

124. In a certain tribal population of India, the prevalence of sickle cell disease, an autosomal recessive condition is 1/100. Based on this value, what proportion of the population would be heterozygous carriers of the sickle cell disease gene in that tribal population

a. 18%
b. 10%
c. 75%
d. 25%

Ans. (a)

125. Cell division cycle is divided into 4 phases G1, S, G2 and M. Standard eukaryotic cell cycles are 12 h or longer duration. Early embryonic cell cycles are extremely rapid having time duration of less than an hour. Which of the following phase are drastically reduced in embryonic cell cycle

a. G1 and G2
b. G1 and S
c. M and S
d. G2 and M

Ans. (a)

126. Ballast water is a serious issue due to possibility of

a. Introduction of polluted water from one site to another site
b. Introduction of marine alien invasive species
c. Release of water from the ship leading to severe upwelling, causing disturbances in ocean currents
d. Several ships anchored near the harbors causing transient localized depletion of water due to uptake of seawater after offloading cargo

Ans. (b)

127. White spot syndrome virus (WSSV) is a major shrimp viral pathogen. Among the WSSV structural proteins, VP28 protein located in the viral envelop plays a major role in invasion of WSSV into shrimp. What would be the ideal strategy for protection against the WSSV infection based on the above information?

a. Adding streptomycin or its analogues that would interfere with the production of VP28 envelop protein
b. Creating a transgenic shrimp that would produce an alkaline protease that in turn would degrade the tail of WSSV virus
c. Supplementing shrimp feed with glucan encapsulating VP28-SiRNA
d. Introducing Lima lima bivalves (filter feeders) which would selectively eliminates the WSSV due to affinity of mantle protein to VP28

Ans. (c)

128. When number of organisms and amounts of living material in successively higher trophic levels are compared, the values usually take the form of a pyramid, with the largest number and greatest biomass in the producer trophic level. However, in some marine ecosystems, the consumer trophic level contains significantly greater amounts of living material than does the primary producer trophic level. Which of the following is the best explanation for this?

a. The main primary producers in marine ecosystems are microscopic algae with extremely high rates of population turnover
b. Most consumers in marine ecosystem are filters feeders that must maintain large basket like structures for extracting food from the water
c. The increased availability of solar radiation in marine ecosystems means that fewer primary producers are required to support marine food chains
d. The largest consumers in marine ecosystems, the baleen whales, are essentially filter feeders

Ans. (a)

129. Microbial rhodopsin is a widespread family of photoactive proteins. Archaebacteria belonging to Halobacteria predominantly contain

a. Bacteriorhodopsin only
b. Halorhodopsin only
c. Sensory rhodopsin only
d. Bacteriorhodopsin, halorhodopsin and sensory rhodopsin

Ans. (d)

130. The Marshall hydrothermal recovery system is a patented proposal

a. To exploit hydrothermal vents for their energy and mineral using dynamically positioned ship or platform position over vent and harnessing the mineral using congenital pipeline
b. To repopulate the dead hydrothermal vents with marine organisms that would scavenge the decaying matter
c. To recover and exploit the shrimps for mariculture
d. With a technology to convert white smokers (low temperature plumes) to black smokers

Ans. (a)

131. Selfish poisoning resulting in permanent short-term memory loss, brain damage and death in severe cases in humans is due to intake of

a. The marine biotoxin called domoic acid produced naturally by marine diatoms and which bioaccumulates in shellfish
b. The marine toxin Okadaic acid that is produced by marine sponge and is accumulated in bivalves
c. Shellfish contaminated by brevetoxins or brevetoxin analogs that are produced by dinoflagellates
d. Saxitoxin produced by harmful algal blooms and accumulated in some shellfish

Ans. (a)

132. The most resistant population of mangroves which normally grow in high salinities inhabit the

a. Ceriops zone
b. Bruguiera zone
c. Rhisophora zone
d. Woodland

Ans. (a)

133. Chitosan, a deacetylated from of chitin (a natural carbohydrate polymer in crab, lobster and shrimps) is used in medicine

a. As a fungicide
b. In plastic surgery to arrest bleeding
c. To remove heavy metal from the skin
d. As an antiseptic cream

Ans. (b)

134. A Slocum Glider, also referred to as an Autonomous Underwater Vehicle (AUV) is used at varying depths in marine waters

a. To monitor microbial films
b. To detect harmful algal blooms
c. For marine biodiversity analysis
d. To study the primary productivity

Ans. (c)

135. A marine bryozoan, normally causing a problem as a biofouler on boats, harbors a bacterium that has shown promise in cancer treatment as well as a memory enhancer for patients with Alzheimer’s. Choose the correct answer from the following

a. Bugula neritina
b. Bugula dentate
c. Cephalosporium acremonium
d. Ectoporcta sp.

Ans. (b)

136. Which of the following regions typically has the highest primary productivity per unit surface area of the ocean?

a. Zone of upwelling
b. Costal water
c. The centres of ocean gyres
d. Tropical waters

Ans. (a)

137. Biofilms interrupt the flow of ions and water to and from the substrate surface by acting as a diffusing barrier. The reduction of localized oxygen can accelerate the corrosion of a metallic substrate and is called microbially induced corrosion (MIC). An example of MIC is

a. Sulphides from SRB which cause the pitting of steel surface
b. Remains of old barnacle exoskeletons
c. Electrostatic interactions and Van der Wall’s forces
d. Crosslinks using cysteine residues

Ans. (a)

138. Antifouling systems that do not use heavy metals are called foul release coatings (FRC). The most effective FRC presently used in the marine environment is

a. Tributyltin (TBT)
b. Biocides such as lead, arsenic, mercury
c. Fluoropolymer and silicone based polymer coatings
d. Spray coatings

Ans. (c)

139. Porites from Scleractinian (stony) corals have been found to be biocompatible and hence used in human systems

a. As structural requirements for bone substitute in cranial surgery
b. As a muscle substitute in heart surgery
c. In the manufacture of biodegradable sutures
d. In corneal transplants

Ans. (a)

140. The first marine derived anti-cancer drug, “Cytosar-U” used for the treatment of leukemia and lymphoma was isolated from

a. Southeast Asian corals
b. A Caribbean sea sponge
c. Indian sea hare
d. Australian waters

Ans. (b)

141. In a pairwise alignment, an optional alignment is one that

a. Either minimizes the implied number of evolutionary changes or minimizes a particular scoring function
b. Either maximizes the implied number of evolutionary changes or minimizes a particular scoring function
c. Either minimizes the implied number of evolutionary changes or maximizes a particular scoring function
d. Either maximizes the implied number of evolutionary changes or maximizes a particular scoring function

Ans. (c)

142. FASTA was the first database search program that

a. Is much faster than Smith Waterman
b. Is much slower than Smith-Waterman
c. Sensitivity and speed of the database search with FASTA are directly related
d. Calculates similarity index

Ans. (a)

143. RMSD between the coordinates of the amino acid gly and its mirror image after superposition will be

a. 0.0 Angstrom
b. More than 1.5 Angstrom
c. More than 3.5 Angstrom
d. More than 6.0 angstrom

Ans. (a)

144. The radius of the following helix types in proteins follows the order

a. Pi helix > alpha helix > 310 helix
b. 310 helix > alpha helix > pi helix
c. 310 helix > pi helix > alpha helix
d. Alpha helix > 310 helix > pi helix

Ans. (a)

145. Needleman-Wunsch algorithm, is an example of dynamic programming, which does not involve

a. Scoring a matrix
b. Setting up a matrix
c. Local alignment
d. Identifying the optimal alignment

Ans. (c)

146. RCSB is

a. An information portal to protein database
b. An information portal to DNA database
c. An information portal to biological macromolecular structures
d. An information portal to microarray

Ans. (c)

147. To identify the presence of repeats in a protein, the simplest and fastest way is to perform a

a. Self dot-plot
b. Dot-plot with another protein with same repeats
c. Dot-plot with another protein with any repeat
d. BLAST search

Ans. (a)

148. The double helical Watson-Crick structure of DNA was first obtained from

a. Fiber diffraction only
b. Fiber diffraction and molecular modeling
c. X-ray diffraction from single crystal
d. Diffraction from single crystals and molecular modeling

Ans. (b)

149. Molecular dynamics differs from molecular mechanics by taking into account

a. The velocities of the constituent particles
b. The effect of the solvent medium
c. The non-bonded interaction
d. The periodic boundary condition

Ans. (a)

150. Which of the following amino acid sequences belong to collagen fibres?

a. Gly-Ala-Gly-Thr-Gly-Ala-Gly-Thr-Gly-Ala-Gly-Thr
b. Gly-Ala-Glu-Ser-Leu-Gly-Ala-Glu-Ser-Leu-Gly-Ala
c. Gly-Ala-Pro-Gly-Pro-Pro-Gly-Thr-Pro-Gly-Ala-Pro
d. Gly-Ala-Glu-Ser-Leu-Gly-Asn-Gly-Ala-Gly-Ala-Glu-Ser-Leu-Gly-Asn

Ans. (c)

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