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Previous Year Questions

TLS Online TPP Program

QUESTION ID:1

Which one of the following is NOT important for regulation of the tryptophan operon by attenuation?

QUESTION ID:2

A plasmid DNA when digested with EcoRI gave a single band of 16 Kb. When the same plasmid was digested with BamHI it gave two bands of 6Kb and 4 Kb. The plasmid has:

QUESTION ID:3

Myeloma cells fused with spleen cells in hybridoma technology are:

QUESTION ID:4

Enzyme inactivation by suicide inhibitors should be:

QUESTION ID:5

Resolution in adsorption chromatography is achieved at:

QUESTION ID:6

Protein kinases phosphorylate proteins at hydroxyl groups on amino acid side chains. Which one of the following groups of amino acids contain side chain hydroxyl groups?

QUESTION ID:7

In a segment of a transcribed gene, the non-template strand of DNA has the following sequence 5‟..AGCTCACTG..3‟. What will be the corresponding 5‟ to 3‟ sequence in the RNA produced from this segment of the gene?

QUESTION ID:8

If the DNA content of a diploid cell in the G1 phase of the cell cycle is X, then the DNA content of the same cell at metaphase of meiosis I would be:

QUESTION ID:9

The α-helix in a protein is primarily due to:

QUESTION ID:10

Amino acids with asymmetric Cβ atoms are:

QUESTION ID:11

The strength of the hydrogen bond represented by D-H...A (where D is the donor atom, H is the hydrogen atom and A is the acceptor atom) depends on

QUESTION ID:12

The van der Waals energy of a single water molecule is:

QUESTION ID:13

What is the minimum number of edges that meet at every branch node in a phylogenetic tree?

QUESTION ID:14

According to the Induced-fit theory, an agonist is defined as:

QUESTION ID:15

A recombinant protein is found to be expressed very poorly in E.coli. It is hypothesized that the expression is blocked at the translational step. The first experimental technique to test this is:

QUESTION ID:16

There are 3 genes A, B and C that are functionally related. There is a point mutation in gene A due to which gene B is not expressed resulting in a nonfunctional
gene C product. What is the possible relationship between these 3 genes?

QUESTION ID:17

Detectable serum antibody against a T-independent pathogen is a good indication that:

QUESTION ID:18

If a 1000 kb fragment of DNA has 10 evenly spaced and symmetric replication origins and DNA polymerase moves at 1 kb per minute, how many minutes will it take to produce two daughter molecules ignoring the potential problem at the end of the linear piece of DNA? Assume that the 10 origins are evenly spaced from each other, none starting from the ends of the chromosome.

QUESTION ID:19

In an experiment, 4 different N-terminal blocked purified proteins were treated with glutaraldehyde, individually. One of the proteins did not get modified. What may be
the reason?

QUESTION ID:20

Which of the following signatures (the stretch of amino acids) in a protein will target it to the nucleus?

QUESTION ID:21

Which one of the following rearrangements is NOT permitted during somatic recombination in the heavy chain and light chain immunoglobulin loci?

QUESTION ID:22

Junctional diversity in CDR3 during gene rearrangement results from the addition of:

QUESTION ID:23

The function of negative selection of thymocytes in the thymus is to eliminate:

QUESTION ID:24

Antigen recognition by T cells in the absence of co-stimulation results in:

QUESTION ID:25

Mutation of homeotic genes often result in which one of the following developmental defects in Drosophila?

QUESTION ID:26

Which one of the following graphs represent the kinetics of ion transport through a membrane channel?

QUESTION ID:27

Transition type of gene mutation is caused when

QUESTION ID:28

Which one of the following is NOT enriched in eukaryotic promoters located in active chromatin?

QUESTION ID:29

One of the reasons why non-substrate inducers (e.g. IPTG) are preferred over substrate inducers (e.g. lactose) for induction of an inducible operon is because:

QUESTION ID:30

In humans, the enzyme having reverse transcriptase activity is:

QUESTION ID:31

To prepare a DNA probe of high specific activity for detecting a single copy gene in a Zoo-blot experiment, which one of the following procedures would be preferred?

QUESTION ID:32

The function performed in the smooth ER is:

QUESTION ID:33

In human carcinomas, many proteins including most cytoskeletal proteins undergo modifications, thereby making it difficult for a clinician to identify the origin of the
cancer cells. In this context, which one of the following can be relied upon for identification of the origin of cancer cells?

QUESTION ID:34

Most organisms can regulate membrane fluidity by changing the lipid composition. If cells are transferred from a warm environment to a cold one, it can be expected
that:

QUESTION ID:35

Glycosylation of membrane proteins and lipids is carried out by enzymes present in the lumen of endoplasmic reticulum and Golgi. The glycosylated part of membrane proteins and lipids in the plasma membrane is likely to be:

QUESTION ID:36

Lysosomal storage diseases are a group of inherited diseases that are characterized by the accumulation of specific substances or class of substances within the lysosomes. All of the following mechanisms can cause lysosomal storage disease EXCEPT:

QUESTION ID:37

The gene encoding an enzyme A that functions in a metabolic pathway for conversion of metabolite „x‟ to „y‟ was knocked out but it still resulted in the formation of metabolite „y‟. From this it can be concluded that:

QUESTION ID:38

The following figure shows the electrophoretic migration of a secretory protein in SDSPAGE from the time of its synthesis (0 min) to its secretion (90 min) from the cells.
Assuming that there was no problem in sample preparation and SDS-PAGE, the reason for a lower band at 30 min and a higher band at 60 and 90 min compared to
that at 0 min could be due to:

QUESTION ID:39

Four yeast mutants block membrane and secretory proteins in following
compartments:
Mutant A: Golgi
Mutant B: Endoplasmic reticulum
Mutant C: Cytosol
Mutant D: Secretory vesicles
If two new mutants are made that have combined defects of A+C and B+D, proteins of the new mutants will accumulate in:

QUESTION ID:40

Asynchronous animal cells were stained with a fluorescent DNA binding dye and analyzed by flow cytometry. The histogram of cell count versus fluorescence
intensity is shown below with or without treatment.

It can be concluded from the histogram that:

QUESTION ID:41

Which one of the following eIF2α kinases get activated during unfolded protein response (UPR) in mammalian cells?

QUESTION ID:42

E. coli RNA polymerase has six subunits two α, one β, one βᶦ, one ω and one σ. Which among these subunits imparts specificity of transcription of a gene and how?

QUESTION ID:43

The use of guide RNA to bind to DNA and target the double strand break at a specific site is a feature of:

QUESTION ID:44

Epidermolysis bullosa simplex (EBS) disease is caused by a mutation in which one of the following genes?

QUESTION ID:45

The genes that have been used for reprograming somatic cells of an adult mammal to stem cells called induced pluripotent stem cells (IPSC) are KLF4, SOX2, OCT4
and c-MYC. These code for:

QUESTION ID:46

Following fertilization, zygote divides rapidly to form a large number of cells within a short time through a process called cleavage. In some organisms like sea urchin
the cells of the early embryos skip some stages of cell cycle in order to achieve this. Which of the following steps may be skipped?

QUESTION ID:47

Cell cycle regulatory genes (cdc) were originally discovered by Paul Nurse in yeasts using genetic approach involving temperature sensitive mutant screening. Which of
the following was used to identify cdc?

QUESTION ID:48

Bindin is a protein that is expressed in the tip of sperm head (acrosome) and is important for sperm-egg interaction. Its distribution pattern changes during sperm maturation. Which one of the following methods may be used to monitor the expression pattern of bindin in a simple light microscope?

QUESTION ID:49

Which of the following mechanisms converts c-erbB (EGFR) to an oncogene?

QUESTION ID:50

Midblastula transition (MBT) is a characteristic process that occurs in early embryogenesis of organisms (like Amphibians) whose eggs are large. MBT refers to:

QUESTION ID:51

Introns which are self-splicing and do not require any cofactor for their splicing, are present in the primary transcripts of:

QUESTION ID:52

The phenomenon of transfer of traits from a man to his grandson through his daughter is known as:

QUESTION ID:53

If the doubling time of a prokaryotic cell becomes progressively shorter, then it can be predicted that the ribosome concentration will:

QUESTION ID:54

How many DNA molecules of 6 base pairs length are possible where the first base is a purine and the last base is a pyrimidine?

QUESTION ID:55

A recombinant protein is expressed in E. coli under T7 promoter at 37oC. However no biological activity is obtained in the cell lysate. If the same experiment is carried
out at 25oC, the cell lysate shows a reasonable biological activity. The most probable explanation for this is:

QUESTION ID:56

IPTG is used as an inducer in the T7 expression system for recombinant protein expression in E.coli. This is because of:

QUESTION ID:57

Pyrosequencing derives its name from the fact that:

QUESTION ID:58

Which of the following is a reason that geneticists use mtDNA to study the relatedness of animal populations?

QUESTION ID:59

Lyophilization is a method used for preservation of microbes because:

QUESTION ID:60

Stoichiometric matrices in metabolic pathways are used in:

QUESTION ID:61

The main difference between domain and motif in protein structure is:

QUESTION ID:62

Select the best algorithm to do pairwise alignment when two proteins are very different in length.

QUESTION ID:63

From literature it is known that the length of an E. coli bacterium is 1 μm with a standard deviation of 0.1 μm. After treatment with chemical “X” the mean length of 100 cells is 1.1 μm with a standard deviation of 0.1 μm. What will you conclude from this experiment?

QUESTION ID:64

Which one of the following techniques CANNOT be used to remove salt from a protein solution

QUESTION ID:65

The jelly roll in protein structure is:

QUESTION ID:66

Which one of the following is NOT a structure or structurally derived database?

QUESTION ID:67

Which of the following is TRUE?
In the threading approaches for prediction of protein structure, the optimization is used for:

QUESTION ID:68

The statistical significance of the BLAST hit is obtained using:

QUESTION ID:69

What is referred by the term k in the following energy expression E = ½ k (b-bo)2 where b and bo refer to the bond length and reference bond length respectively?

QUESTION ID:70

The estimates of number of false positives from a BLAST search can be made using:

QUESTION ID:71

The length of Beta Hairpin motif is usually:

QUESTION ID:72

A scoring function is used in which one of the following drug design technologies?

QUESTION ID:73

BLOSUM matrices are based on:

QUESTION ID:74

ProDom is a comprehensive set of protein domain families automatically generated from:

QUESTION ID:75

Which one of the following methods used to find evolutionary trees is also referred as “the minimum evolution method”?

QUESTION ID:76

Z-score =

QUESTION ID:77

In a sequence logo of the type given below, the sizes of the letters are proportional to the:

QUESTION ID:78

For a homology search program such as BLAST, which one of the following best describes the scoring pattern?

QUESTION ID:79

Given the results of a 'sequence versus fingerprint' search, which of the following would be considered the best hit?

QUESTION ID:80

In a Multi-Locus Variable number tandem repeat Analysis (MLVA) for Salmonella enterica subspecies, three tandem repeats loci have been identified inside yohM gene of S. typhimurium LT2, S.typhi CT18 and S.typhi Ty2 strains. Motif lengths for the loci are 2,3 and 5 respectively. Motif AT and ATG are found to be repeated by 13 and 5 times respectively in all the strains. Motif ATGTC is repeated 13 times in S. typhimurium LT2, 15 times S.typhi CT18 and 12 times S.typhi Ty2 strains. Which locus is Variable Number Tandem Repeat (VNTR)?

QUESTION ID:81

Of a population of cells undergoing meiosis, 1% of the cells undergo recombination between genes A and B. What is the distance between the two genes?

QUESTION ID:82

Which one of the following combinations of marker genes and promoters CANNOT be used for selection of transgenic plants under in vitro conditions?

QUESTION ID:83

Several experiments have shown leaky/deregulated expression of reporter genes viz., GUS from plant promoters in Agrobacterium cells. Which one of the following approaches would be most useful in restricting transgene expression in transformed plant cells and prevent their expression in Agrobacterium?

QUESTION ID:84

A T0 transgenic plant showing two copies of T-DNA on Southern analysis, segregated in a 3:1 ratio for the transgenic:non-transgenic phenotype among T1 progeny obtained by self-pollination. Which one of the following statements best explains this observation?

QUESTION ID:85

Which one of the following statements is correct?

QUESTION ID:86

Which one of the following statements related to transgene silencing in plants is INCORRECT?

QUESTION ID:87

Two independent transgenic plants, one with single copy of gene A and another with single copy of gene B were expressed under the same seed-specific promoter. In transgenic plants, seed formation on self-pollination was similar to that of untransformed plants. When homozygous plants with gene A (male parent) were crossed with homozygous plants with gene B (female parent), viable seed formation did not occur although, pollen production was normal. What could be the possible reason for this observation?

QUESTION ID:88

The range of transformation frequencies obtained in independent transformation experiments using four different constructs with different combinations of promoters (Pr)  and selection marker genes, is given below:
In the absence of any other factors, which one of the following statements is NOT acceptable as a logical conclusion based on the above data?

QUESTION ID:89

Callus-mediated regeneration is NOT preferred for micropropagation because:

QUESTION ID:90

In a transgenic plant, the phenomenon of Co-suppression is due to:

QUESTION ID:91

In inbred lines, gene and genotypic frequencies are maintained by growing them in isolation followed by:

QUESTION ID:92

Homozygous plants from bi-parental mating for development of mapping populations can be obtained in a short time by:

QUESTION ID:93

Which one of the following is NOT required for QTL analysis in association mapping?

QUESTION ID:94

Which one of the following hormones promote production of seedless grapes?

QUESTION ID:95

Which one of the following molecular markers is associated with bacterial blight resistance in rice?

QUESTION ID:96

Match the proteins in Group I with members in Group II

QUESTION ID:97

Application of the herbicide, phosphoinothricin, results in death of plants due to accumulation of:

QUESTION ID:98

Which one of the following is NOT a feature of Agrobacterium VirE protein?

QUESTION ID:99

Transgenic potato plants with high amylose starch were developed by:

QUESTION ID:100

Developing cisgenic disease resistant apple is advantageous over conventional breeding because:

QUESTION ID:101

For development of selection marker-free transgenic plants by co-transformation using Agrobacterium, the marker genes are:

QUESTION ID:102

Breakdown of Bt- mediated insect resistance in crops can be delayed by:

QUESTION ID:103

Which one of the following is matched INCORRECTLY?

QUESTION ID:104

Which one of the following would produce androgenic haploids in anther culture?

QUESTION ID:105

Male sterility in plants is induced by expression of the TA29-barnase-pA cassette in:

QUESTION ID:106

Anchorage dependent CHO cells are grown by aeration using micro carrier beads. The maximum detrimental effect of shear occurs due to agitation if the size (Kolmogorov scale) of eddies is:

QUESTION ID:107

With progress in the growth of E. coli in a minimal medium (constant aeration and agitation), the dissolved oxygen (DO) initially declined and then started to increase. If the DO again starts to decrease on addition of glucose, then the most probable explanation is:

QUESTION ID:108

An organism obeys Andrews model for growth inhibition with Ks and Ki values of 0.01 g/l and 1.0 g/l respectively. If the substrate is present at an initial concentration of 1.0g/l, the specific growth rate of the culture upon entering log phase would be approximately:

QUESTION ID:109

In a stirred tank reactor when the agitation rate is increased, the kL and kLa values will:

QUESTION ID:110

Which one of the following is correct regarding cell damage in an agitated and sparged mammalian cell bioreactor?

QUESTION ID:111

Which one of the statements given below is NOT true? Equilibrium constant (K) of a chemical reaction at a specific temperature can be determined if the:

QUESTION ID:112

If a big centrifuge with the bowl diameter of 1m rotates at 60 rpm, at what speed (rpm) does a smaller centrifuge with a diameter of 0.5 m need to be operated for achieving the same separation factor?

QUESTION ID:113

What is the linear flow rate (superficial velocity in cm/h) in a chromatographic column of 1.0 cm inner diameter with a bed porosity of 0.8 when the volumetric flow rate is 1 ml/min?

QUESTION ID:114

For a cell growth process, the units for yield, productivity and titre are:

QUESTION ID:115

In a fermentor the impeller diameter is increased from 0.5 m to 1 m and the rpm is increased from 100 rpm to 400 rpm. Reynolds number will increase by?

QUESTION ID:116

Zymomonas mobilis is cultivated in a 60 l chemostat. The μmax and Ks values are 0.2 h-1 and 0.5 g l-1 respectively. The flow rate (l h-1) required for a steady state substrate concentration of 0.5 g l-1 in the reactor is:

QUESTION ID:117

Which one of the following statements is WRONG for conventional batch filtration of a mycelial fermentation broth?

QUESTION ID:118

The reason for the choice of E. coli for the production of ethanol from lignocellulose is because it:

QUESTION ID:119

Two organisms A and B with the same μmax and Yx/s are cultivated independently in batch culture. They have Ks values of 1 g.l-1 and 3 g.l-1 respectively. Given that the initial substrate concentration was 5 g/l, which of the following is TRUE after complete exhaustion of the substrate?

QUESTION ID:120

Pseudomonas with the elemental composition of CH3O0.5N0.5 (MW = 30) is grown in a bioreactor to a final cell mass of 30 g/l. The minimum concentration (g/l) of ammonia (NH3) (MW = 17) (as the sole nitrogen source) required is:

QUESTION ID:121

To reduce the level of deactivation of media components for culturing Lactobacillus spp., a high temperature and short time (HTST) regime is used for sterilization,
PRIMARILY because:

QUESTION ID:122

Acetobacter aceti converts alcohol to acetic acid according to the stoichiometric relation
C2H5OH + O2  → CH3COOH + H2O
In a vigorously agitated and aerated reactor containing 20 g/l ethanol, the organism produces 16 g/l acetic acid and 2 g/l was the residual ethanol concentration. What are the theoretical and observed yields of acetic acid expressed in g/g ethanol?

QUESTION ID:123

A continuous stirred tank bioreactor produces 48 kg lysine.day-1. If the volumetric productivity is 2 g.l-1.h-1, the volume of the reactor is:

QUESTION ID:124

Aqueous Two Phase System (ATPS) is used to isolate a protease from a fermentation broth. The partition coefficient (K) is 2.5. For 80 % recovery of protease in a single step, the volume ratios of upper and the lower phases should be:

QUESTION ID:125

To have an overall yield of greater than 50% in a three step purification process for a food additive, the minimum average step yield(%) necessary would be around:

QUESTION ID:126

In a fed batch process for the production of an antibiotic, the dissolved oxygen (DO) level was found to be falling below 30%. If the DO level of 30% is to be maintained in
the reactor (without altering the composition of oxygen-air mixture, aeration rate and agitation) then we need to:

QUESTION ID:127

In a batch sterilization process if ∇overall , ∇heating & ∇cooling are 32.2, 9.8 & 10.1 respectively, THEN the holding time at 121ºC of the process is (given that the specific
death rate (k) of microorganisms at 121ºC is 2.54 min-1 ):

QUESTION ID:128

To achieve complete separation of two pharmaceutical compounds (shown as two peaks in the chromatogram), the relative separation (RS) should be:

QUESTION ID:129

The anticancer drug, Halichondrin – D is isolated from:

QUESTION ID:130

Heparin is a:

QUESTION ID:131

The only naturally transformable marine cyanobacteria is:

QUESTION ID:132

Marine chemosynthesis is mainly based on:

QUESTION ID:133

Which one is a DNA replication blocking agent produced by sponges?

QUESTION ID:134

Eutrophication in aquatic ecosystems is due to reduction of:

QUESTION ID:135

Halotolerant and halophilic microbes can be isolated from ------ and -------, respectively.
P. Sea Q. River R. Lake S. Estuary

QUESTION ID:136

Heavy metal pollutants like Cd and Hg inactivate enzymes by interacting with:

QUESTION ID:137

Which of the following class of enzymes initiates aerobic degradation of aromatic pollutants (like naphthalene) in bacteria?

QUESTION ID:138

Which one of the following organisms is NOT able to perform light harvesting reaction?

QUESTION ID:139

In the soil environment, which one of the following factors is responsible for the biotic stress on the microbial community?

QUESTION ID:140

Match the enzymes in Group I with their appropriate role in the environment from Group II

QUESTION ID:141

Which one of the following types of mutation would usually NOT be detected in a molecular diagnostic test that is based on sequencing each exon of a gene individually
from a male suspected of having an X-linked disorder?

QUESTION ID:142

A couple came for counselling following three first-trimester miscarriages and underwent chromosomal analysis. The man was found to have pericentric inversion with the karyotype 46,XY,inv8(p12q22). Which one of the following would be a correct conclusion?

QUESTION ID:143

Unequal crossing over between two Alu repeats can lead to an LDL receptor gene with an internal deletion or duplication. Based on this information, which of the following must be true?

QUESTION ID:144

Linkage analysis is performed in a large family with an autosomal dominant hemolytic anemia, using a polymorphic marker within the β-globin locus. The LOD score at q=0 is negative infinity. The LOD score at q=0.01 is -4.5. You conclude that the disorder in this family is:

QUESTION ID:145

In Li-Fraumeni syndrome most frequent mutation occurs in:

QUESTION ID:146

Which one of the following promoters is most efficient for transgene expression in mammary gland of livestock?

QUESTION ID:147

Epinephrine is used along with local anaesthetic because of its:

QUESTION ID:148

Founder effects and bottlenecks are:

QUESTION ID:149

In commercial farms, embryos are routinely recovered by non-surgical methods. On which day are the embryos recovered from the donor cow after the onset of estrus?

QUESTION ID:150

Human mesenchymal stem cells:

QUESTION ID:151

Vectors are important in transmission of diseases. Match group 1 with group 2.

QUESTION ID:152

Which one of the following is an inhibitory neurotransmitter?

QUESTION ID:153

Huntington‟s disease is clinically characterized by chorea (abnormal involuntary movements). Which part of the brain is responsible for this phenotype?

QUESTION ID:154

α-Amanitin is a fungal toxin which inhibits eukaryotic RNA polymerases. The three eukaryotic RNA polymerases show differential sensitivity to this toxin. Which one of the following order (higher to lower) is correct with respect to sensitivity towards α-amanitin?

QUESTION ID:155

A primary cell culture can be transformed into a cell line by all EXCEPT:

QUESTION ID:156

In a randomly breeding population, an autosomal recessive condition affects 1 newborn in 10,000. The expected frequency of carriers will be nearly:

QUESTION ID:157

Assessment of the extent of DNA double strand breaks in cultured human cells, following exposure to ionizing radiation, can be done by quantitation of :

QUESTION ID:158

There are reports of more than 100 mutations at different sites of Factor IX that manifests Haemophilia B. This is an example of:

QUESTION ID:159

Specificity factor which activates ubiquitin ligase activity of APC/C during separation of sister chromatids is:

QUESTION ID:160

In a diploid organism, loss of function mutations produce dominant phenotypes when there is:

QUESTION ID:161

In Mendel‟s dihybrid cross experiment, if the two selected traits were on the same chromosome (linked) and assuming that there is no recombination, what would be the
expected genotypic ratio in the F2 generation?

QUESTION ID:162

Huntington disease is caused by:

QUESTION ID:163

The following pedigree shows the inheritance of a very rare human disease. What is the most likely mode of inheritance for the disease trait and what is the probability that the second child of III-2 and III-3 will be a son and will also have the disease?

QUESTION ID:164

Microscopic evaluation of a post-mortem brain exhibits hyperchromatic areas when stained with glial fibrillary acidic protein (GFAP). This suggests activation of:

QUESTION ID:165

Parasite numbers in the blood of a patient with Trypanosoma brucci (Sleeping sickness) shows the following pattern:

Parasites isolated from population 1 and 2 were found to be antigenecially noncross reactive. The parasite distribution seen may be due to: