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Previous Year Questions

TLS Online TPP Program

QUESTION ID:1

In an experiment the structural genes lacZYAof lac operon were found to be constitutively expressed. The following explanations were given for the constitutive expression
(P) absence of a functional repressor due to mutation in the repressor gene lacI
(Q) mutation in the operator that can no longer bind the repressor
(R) mutation in the lacAgene
Which of the following is CORRECT

QUESTION ID:2

Which one of the following is TRUE about siderophores in bacteria?

QUESTION ID:3

In a population containing fast and slow growing bacteria, the slow growing bacteria can be enriched by supplementing the medium with

QUESTION ID:4

When the supply of tryptophan is plentiful, the tryptophan operon is repressed because the

QUESTION ID:5

Match the scientists in Group I with their contributions in microbiology in Group II

QUESTION ID:6

Match the infectious agents in Group I with the associated diseases in Group II


QUESTION ID:7

Match the microscopes in Group I with their working principles in Group II


QUESTION ID:8

In a phenol coefficient test for determining the efficacy of a disinfectant X, the maximum effective dilution for X and phenol was found to be 1/450 and 1/90, respectively. Calculate the phenol coefficient for X.

QUESTION ID:9

How many electrons are accepted when sulfate acts as the terminal electron acceptor in bacteria such as Desulfovibrio?

QUESTION ID:10

A bacterial population increases from 103 cells to 109 cells in 10 h. Calculate the number of generations per hour.

QUESTION ID:11

Which one of the following provides the strongest support for the theory of “descent with modification”?

QUESTION ID:12

Which one of the following is an example of sympatric speciation?

QUESTION ID:13

The primary difference between glycogen and cellulose is in the

QUESTION ID:14

Control mechanisms operate at any of the several steps involved in gene expression. Which one of the following is the key mode of regulation during the cell cycle?

QUESTION ID:15

Testicular feminization syndrome is a genetic condition wherein an individual with a XY genotype will have an external female-like phenotype. This is caused by

QUESTION ID:16

Which one of the following defects do you expect to see if you were able to specifically block apoptosis in the developing limb bud of a frog embryo?

QUESTION ID:17

The formation of antigen-antibody complex helps in disposing antigen through the following pathways EXCEPT:

QUESTION ID:18

The term “ecological succession” refers to:

QUESTION ID:19

Which one of the following options provide example for the term “habituation” in behavioral ecology?

QUESTION ID:20

Among the following cell structure-function pairs, identify the correctly paired one

QUESTION ID:21

Which of the following most accurately states the goal of systematics?

QUESTION ID:22

Among the following options, choose the one that is probably a cause of rapid diversification of animal groups during the Cambrian explosion.

QUESTION ID:23

A newly discovered, recessively-inherited disease-susceptibility trait (DS) is observed only in cotton plants with white flowers, although the flower colour (R) and DS are independently inherited. In a breeding programme, one variety that is homozygous for the absence of DS, but heterozygous for R was mated to another having white flowers but heterozygous for DS. What is the probability that a given plant among the cross progeny will be susceptible to the disease?

QUESTION ID:24

In a new species of moth, the genes for body colour (black, B, is dominant over grey, b), wing size (normal wing, W, is dominant over vestigial, w) and eye colour (red, R, is dominant over white, r) are linked. In this species, only one cross-over event has been observed between any two homologous chromosomes during meiosis. In a cross between BB; ww and bb; WW, 5 % of the progeny were black with normal wings. In a separate cross between RR; WW and rr; ww, 15 % of the progeny were red-eyed with vestigial wings. In a third cross between BB; rr and bb; RR, 10 % of the progeny were black-coloured with red eyes. Which among the following is the correct order
of these three genetic loci?

QUESTION ID:25

In vertebrates, the variations in the structure and function of nephrons are directly linked to the osmoregulatory requirements of the organisms depending on the habitats they live in. From the options given below, identify the correct combination that truly represents the adaptation seen in desert mammals:
i. Long loops of Henle
ii. Short loop of Henle
iii. Hyperosmotic urine
iv. Large volume of urine
v. Removal of nitrogen as uric acid

QUESTION ID:26

In Drosophila, mutations in homeotic genes result in which one of the following developmental defects?

QUESTION ID:27

Retroviruses, like the influenza virus, escape the detection of pre-existing antibodies in the host by generating surface antigen variants. They do so:

QUESTION ID:28

The relative number of individuals in each age group is an important demographic factor for the study of future growth trends, and this is normally depicted in the form of an age-structure pyramid. Based on your understanding on population dynamics, match the following distribution properties of age structure (Group 1) with the individual forecast given (Group 2):
Group 1
I). Uniform age distribution in the pyramid
II). Distribution skewed towards younger age groups
III). Distribution skewed towards older age groups
IV). Reduction in the number of males in the middle age group
Group 2
i). Emigration in the recent past and the possible increase in the older age groups in the near future.
ii). Likely to be a stable population
iii). Possible unemployment in the near future
iv). Increased government expenditure on medical needs and social security related issues in the near future

QUESTION ID:29

Like any other trait, animal behavior also evolves by natural selection. Which one of the following examples is NOT true with regard to the evolution of behavior by natural selection?

QUESTION ID:30

Among the following molecular process-biological effect pairs, identify the mismatched pair.

QUESTION ID:31

Kawashiorkor disease is caused due to the deficiency of

QUESTION ID:32

Which of the following statements is TRUE in case of oxidative rancidity of vegetable oils and fats?

QUESTION ID:33

The food borne disease, Q fever is caused by the organism

QUESTION ID:34

The primary bacterial spoilage of poultry meat at low temperature, with characteristic sliminess at outer surface, is caused by

QUESTION ID:35

The weight gain (in gram) per gram protein consumed is called

QUESTION ID:36

Which of the following carbohydrates is NOT classified as dietary fibre?

QUESTION ID:37

In the extruder barrel, the compression is achieved by back pressure created by the die and by

QUESTION ID:38

The brown colour of bread crust during baking is due to Maillard reaction between

QUESTION ID:39

Blanching influences vegetable tissues in terms of

QUESTION ID:40

When garlic is cut or processed, the crushed garlic odour is due to the formation of

QUESTION ID:41

Match the toxicants of plant foods in Group I with their main plant source given in Group II.

QUESTION ID:42

Match the products in Group I with the enzymes used for their preparation given in Group II.

QUESTION ID:43

Match the food items in Group I with the type of colloidal dispersion given in Group II.

QUESTION ID:44

[a] Assertion: In the presence of sucrose, the temperature and time for gelatinization of starch increases.
[r] Reason: Sucrose, due to its hygroscopic nature, competes with starch for water needed for gelatinization.

QUESTION ID:45

Thermal death of viable spores of Bacillus subtilis in a food sample follows a first order kinetics with a specific death rate constant of 0.23 min-1 at 100°C. The time (in minutes) required to kill 99% of spores in the food sample at 100°C will be

QUESTION ID:46

How much skim milk (in kg) containing 0.1% fat should be added to 500 kg of cream containing 50% fat to produce standardized cream containing 36% fat?

QUESTION ID:47

Which of the following statements is NOT CORRECT in relation to muscle proteins ?

QUESTION ID:48

A cold storage plant is used for storing 50 tonnes of apples in perforated plastic crates. During the storage, apples are cooled down from 28°C to storage temperature of 2°C. (Specific heat of the apple = 0.874 kCal kg-1 °C-1). If the required cooling is attained in 16 hours, the refrigeration plant capacity (in Tons) is

QUESTION ID:49

An actively growing culture of Acetobacter aceti is added to the vigorously aerated fermented fruit juice medium containing 10 g l-1 ethanol to produce vinegar. After some time, the ethanol concentration in the medium is 0.8 g l-1 and acetic acid produced is 8.4 g l-1. What is the conversion efficiency of the process with respect to theoretical yield?

QUESTION ID:50

An enzyme catalyzed reaction (following Michaelis-Menten kinetics) exhibits maximum reaction velocity (Vm) of 75 nmol l-1 min-1. The enzyme at a substrate concentration of 1.0x10-4 M shows the initial reaction velocity of 60 nmol l-1 min-1. The Km value of the enzyme in molar concentration (M) is