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Previous Year Questions

TLS Online TPP Program

QUESTION ID:1

An enzyme catalyzes a reaction by 

QUESTION ID:2

Natural proteins are composed primarily of 20 a-amino acids. Which one of the following statements is true for any of these amino acids in a solution of pH 1.5? 

QUESTION ID:3

Which one of the following organisms is an indicator of fecal contamination? 

QUESTION ID:4

The surface area (in m^2) of the largest sphere that can fit into a hollow cube with edges of length 1 meter is . 

Given data:   = 3.14 

QUESTION ID:5

In a thin layer chromatography experiment using a silica gel plate, a compound showed migration of 12.5 cm and the solvent front showed migration of 18 cm. The Rf value for the compound is  

QUESTION ID:6


QUESTION ID:7

Which one of the following mechanisms is used by human pathogens to evade host immune responses? 

QUESTION ID:8

If the nucleotide composition (%) of a viral genome is A = 10, U = 20. C = 40, and G = 30, which one of the following is this genome? 

QUESTION ID:9

Which one of the following techniques can be used to determine the structure of a 15 kDa globular protein at atomic resolution? 

QUESTION ID:10

Assertion [a]: Gram negative bacteria show staining with saffranin.

Reason [r]: Gram negative bacteria have an outer membrane with lipopolysaccharides.

QUESTION ID:11

The plant hormone indole-3-acetic acid is derived from 

QUESTION ID:12

Enzyme-linked immunosorbent assay (ELISA) is used for

QUESTION ID:13

Macrophages eliminate pathogenic bacteria upon activation by

QUESTION ID:14

If a protein contains four cysteine residues, the number ofratfferent ways they can simultaneously form two intra-molecular disulphide bonds is 

QUESTION ID:15

Secretory proteins synthesized by ER-associated ribosomes traverse through 

QUESTION ID:16


QUESTION ID:17

During protein synthesis, tRNAs are NOT involved in 

QUESTION ID:18

In eukaryotes. cytokinesis is inhibited by 

QUESTION ID:19

A proto-oncogene is suspected to have undergone duplication in a certain type of cancer. Of the following techniques. which one would verify the gene duplication?

QUESTION ID:20

A polymerase chain reaction (PCR) was set up with the following reagents: DNA template, Tag polymerase. buffer. dNTPs. and Me. Which one of the following is missing in the reaction mixture? 

QUESTION ID:21

An enzymatic reaction exhibits Michaelis-Menten kinetics. For this reaction. on doubling the concentration of enzyme while maintaining [S] >> [Eo], 

QUESTION ID:22

A 5 liter chemostat is fed fresh medium at 0.2 liters/minute having a substrate concentration of 25 grams/liter. At steady state, the outgoing stream has substrate concentration of 2.5 grams/liter. The rate of consumption (grams/liter/minute) of the substrate in the reactor is  

QUESTION ID:23

The transcription factor X binds a 10 base pair DNA stretch. In the DNA of an organism, X was found to bind at 20 distinct sites. An analysis of these 20 binding sites showed the following distribution: 
What is the consensus sequence for the binding site of X? 

QUESTION ID:24

A bacterium has a genome of size 6 million base pairs. If the average rate of DNA synthesis is 1000 base pairs/second. the time taken (in minutes) for replication of the genome will be 

QUESTION ID:25

At the transcription start site of a gene. any of the four nucleotides can occur with equal probability p. The Shannon Entropy , for this start site is  

Given data: ln(2) = 0.69

QUESTION ID:26

Which one of the following graphs represents the kinetics of protein precipitation by addition of ammonium sulphate? On the Y-axis, [Protein] represents the concentration of free protein in solution. 


QUESTION ID:27

The distribution of marks scored by a large class in an exam can be represented as a normal distribution with mean g and standard deviation a. In a follow-up exam in the same class, everyone scored 5 marks more than their respective score in the earlier exam. For this follow-up exam, the distribution of marks can be represented as a normal distribution with mean µ2 and standard deviation σ2. Which one of the following is correct? 

QUESTION ID:28

The angle (in degrees) between the vectors

QUESTION ID:29

Match the proteins in Group I with cellular processes in Group II 

QUESTION ID:30

The circular dichroism spectra of three proteins P, Q, and R are given below: 

Choose the correct combination. 

QUESTION ID:31

Match the organisms in Colman I with the characteristics in Column II 

QUESTION ID:32

Which one of the following amino acids has three ionizable groups? 

QUESTION ID:33

Consider an infinite number of cylinders. The first cylinder has a radius of 1 meter and height of 1 meter. The second one has a. radius of 0.5 meter and height of 0.5 meter. Every subsequent cylinder has half the radius and half the height of the preceding cylinder. The sum of the volumes (in cubic meters) of these infinite number of cylinders is    Given data: Ï€= 3.14.

QUESTION ID:34

The concentration (in micromolar) of NADH in a solution with A340 = 0.50 is  Given data: Path length = 1 cm; Molar extinction coefficient of

QUESTION ID:35

The specific activity of an enzyme in a crude extract of E. co/i is 9.5 units/mg of protein. The specific activity increased to 68 units/mg of protein upon ion-exchange chromatography. The fold purification is  

QUESTION ID:36

 Which one of the following organisms is responsible for crown gall disease in plants? 

QUESTION ID:37

The value of the which the following system of linear equations has an infinite number of solutions 

QUESTION ID:38

Match the plant hormones in Column I with ftmctions in Column II 


QUESTION ID:39

For an E. coli culture in the exponential phase of growth, optical density (OD) at 540 mn is 0.3 at 2 hours and 0.6 at 4 hours. Assuming that the measured OD is linearly proportional to the number of E. coli cells, the gourd' rate (per hour) for this culture is  

QUESTION ID:40

An immunocompetent person becomes infected with a pathogenic strain of bacteria. Which one of the following graphs correctly depicts bacterial load in this person over tune? 

QUESTION ID:41

The genome is diploid at the end of which phases of a human mitotic cell cycle?

QUESTION ID:42

A recombinant protein is to be expressed under the control of the lac promoter and operator in a strain of E coil having the genotype lacl^+ arp^+ Even in the absence of inducer IPTG, low levels of expression of the recombinant protein are seen (leaky expression). Which one of the following should be done to minimize such leaky expression?

QUESTION ID:43

Shown below is a plasmid vector (P) and an insert (Q). The insert was cloned into the BamH1 site of the vector. The recombinant plasmid was isolated and digested with Bansill or XhoL The results from the digestion experiments are shown in (R)
Which one of the following explains the digestion results shown in (R)? 

QUESTION ID:44

Which one of the following CANNOT be a recognition sequence for a Type II restriction enzyme? 

QUESTION ID:45

A pedigree of an inheritable disease is shown below. 

This inheritable disease is 

QUESTION ID:46

If the chemical composition of proteins in an organism is , the mass percentage of carbon in the proteins is  
Given data: Atomic weights (Da) of C = 12, H = 1, 0 = 16. N = 14, and S = 32. 

QUESTION ID:47

For the probability density

QUESTION ID:48

Growth of a microbe in a test tube is modeled as dX/dt = rX (1 - x/K), where, X is the biomass, r is the dt growth rate, and K is the carrying capacity of the environment (r â‰  0; K â‰  0). If the value of starting biomass is K/100, which one of the following graphs qualitatively represents the growth  dynamics? 

QUESTION ID:49

A zero-order liquid phase reaction is being carried out in a batch reactor with k =10^-3 mol/min. If the starting concentration of A is 0.1 moles/liter. the time (in minutes) taken by the system before A is exhausted in a 100 liter reactor is 

QUESTION ID:50

The interaction energy E between two spherical particles is plotted as a function of the distance (r) between them. When r<a, where a is a constant, the net force between the spherical particles is repulsive. When they attract via van der Waals attraction. Which one of the following plots correctly represents the interaction energy between the above two particles? 

QUESTION ID:51

EcoRI restriction sites on a 10kb DNA fragment are shown below. 
Upon partial digestion, what are the lengths (in kb) of all the possible DNA fragments obtained? 

QUESTION ID:52

A DNA strand of length 25 mn wraps diametrically around the circumference of a spherical histone-octamer once. The radius (nm) of the histone-octamer is  
Given data: Ï€ = 3.14 

QUESTION ID:53

One hundred E. coli cells are each infected by a single λ phage particle. The ratio of the number of phage particles committing to lysogeny to those committing to lysis is 4:1. Assuming that the average burst size is 80, the number of free phage particles released after one round of infection is  

QUESTION ID:54

During anaerobic growth, an organism converts glucose (P) into biomass (Q). ethanol (11), acetaldehyde (S), and glycerol (T). Every mole of carbon present in glucose gets distributed among the products as follows: 
1 (C-mole P) 0.14 (C-mole Q) + 0.25 (C-mole R) + 0.3 (C-mole S) + 0.31 (C-mole T)
From 1800 grams of glucose fed to the organism, the ethanol produced (in gains) is 
Given data: Atomic weights (Da) of C = 12, H = 1 0 = 16, and N = 14

QUESTION ID:55

Which of the following conditions promote the development of human autoimmune disorders? 
P. Inability to eliminate self-reactive lymphocytes
Q. Generation of auto-antibodies
R. Ability to eliminate self-reactive T-cells
S. Induction of regulatory T-cells in the thymus 

QUESTION ID:56

She has a sharp tongue and it can occasionally turn  

QUESTION ID:57

I .....................   made arrangements had I informed earlier. 

QUESTION ID:58

In the sununer. water consumption is known to decrease overall by 25%. A Water Board official states that in the summer household consumption decreases by 20%. while other consumption increases by 70%.  Which of the following statements is correct?

QUESTION ID:59

40% of deaths on city roads may be attributed to drunken driving. The number of degrees needed to represent this as a slice of a pie chart is 

QUESTION ID:60

Some tables are shelves. Some shelves are chairs. All chairs are benches. Which of the following conclusions can be deduced from the preceding sentences?
i. At least one bench is a table
ii. At least one shelf is a bench
iii. At least one chair is a table
iv. All benches are chain 

QUESTION ID:61

If you are looking for a history of India. or for an account of the rise and fall of the British Raj. or for the reason of the cleaving of the subcontinent into two mutually antagonistic parts and the effects this mutilation will have in the respective sections. and ultimately on Asia. you will not find it in these pages; for though I have spent a lifetime in the country. I lived too near the seat of events. and was too intimately associated with the actors, to get the perspective needed for the impartial recording of these matters".
Here. the word 'antagonistic' is closest in meaning to 

QUESTION ID:62

S. T. U, V, W. X. Y. and Z are seated around a circular table. T'S neighbours are Y and V. Z is seated third to the left of T and second to the right of S. Cs neighbours are S and Y; and T and W are not seated opposite each other. Who is third to the left of V? 

QUESTION ID:63

Trucks (10 m long) and cars (5 m long) go on a single lane bridge. There must be a gap of at least 20 m after each truck and a gap of at least 15 m after each car. Trucks and cars travel at a speed of 36 km/h. If cars and trucks go alternately. what is the maximum number of vehicles that can use the bridge in one hour? 

QUESTION ID:64

There are 3 Indians and 3 Chinese in a group of 6 people. How many sub groups of this group can we choose so that every sub group has at least one Indian? 

QUESTION ID:65

A contour line joins locations having the same height above the mean sea level. The following is a contour plot of a geographical region. Contour lines are shown at 25 in intervals in this plot.

The path from P to Q is best described by