Previous Year Questions

QUESTION ID:2

Assuming that the histone octamer forms a cylinder 9 nm in diameter and 5 nm in height and that the human genome forms 32 million nucleosomes, what fraction (approximately)of the volume of nucleus (6 μm diameter ) is occupied histone octamers?

QUESTION ID:3

A reporter cell line with stably integrated retroviral promoter-luciferase construct was transfected with an expression vector for a cellular protein. The protein seems to regulate the activation of retroviral promoter as analyzed by luciferase activity assay. Which one of the following techniques will you use to show “in vivo” recruitment of the cellular protein on the integrated retroviral promoter?

QUESTION ID:4

In a tissue,cells are bound together by physical attatchment between cell to cell oe between cell to extra cellular matrix. Following are some of the characterstics of cell junctions:
(A) Aderens junctions are cell-cell anchoring junctions connecting actin filament in one cell with that in next cell.
(B) Desmosomes are cell-matrix anchoring junctions connecting actin filament to extra cellular matrix
(C) gap junctions are channel for,ming junctions allowing passage of small water soluble molecules from cell to cell.
(D) Tight junctions are occluding junctions,which seal gap between two cells
(E) Hemidesmosomes are cell-matrix anchoring junctions connecting intermediate filament in one cell to extra cellular matrix.
Which of the following combinations of statements is NOT correct?

QUESTION ID:5

A mouse was primed with trinitrophenyl - lipopolysaccharide (TNP-LPS) whereas another mouse was primed with TNP-keyhole limpet hemocyanain (TNP-KLH). After three weeks, these mice were sacrificed and splenic cells were fractionated to B cells and T cells. B cells from TNP-LPS primed mice were co-cultured with T cells from TNP-LPS or TNP-KLH-primed mice. Similarly, B cells from TNP-KLH primed mice were co-cultured with the T cells from TNP-LPS or TNPKLH- primed mice. So, we have four co-cultures Among these co-cultures, where do you except the highest IgG production?

QUESTION ID:6

A large protein of a pathogenic bacterium has been enzymatically digested to generate a mixture of peptides ranging in size from 3 to 8 amino acids in length. Peptide mixtures were then administered in experimental animals to generate peptide-specific antibodies. In order to develop diagnostics for the bacteria, the antisera were used Western blotting to detect bacterial antigen. Western blotting failed despite the use of a wide range of antisera concentrations. What is the most probable cause of the problem?

QUESTION ID:7

Ten different mouse strains were primed with whole Keyhole limplet hemocyanin (KLH). KLH was broken into 10 peptides for in vitro stimulation. The splenocytes from ten different primed mouse strains were re-stimulated with each of these 10 peptides and responsiveness to these were measured in vitro. It was found that each of these mouse strains had responded to one of the peptides. When the peptide 3 responder was mated with peptide 4 responder, the splenocyte of F1 offsprings responded to both the peptide.
Which of the following is most appropriate

QUESTION ID:8

Upon ligand binding, cell surface receptors move laterally to be capped and internalized. Leishmania a protozoan parasite, can use several receptors on macrophages to get internalized.one of them is Toll-like receptor 2 (TLR2) that binds lipophosphoglycan on Leishmania. Once internalized, the parasite is destroyed in the phagolysosome. Which of the following treatments of Leishmania-infected macrophages will result in lowest parasite number in macrophages?

QUESTION ID:9

Oncogenes and tumor suppressor genes are termed as cancer-critical genes. Increasingly powerful tools are now available for systematically searching the DNA or mRNAs of cancer cells for either significant mutations or altered expression. To identify independently an oncogene or a tumor suppressor gene, which of the following would be the most convincing tests to be used?

QUESTION ID:10

The functionality of the pax6 gene in the formation of optic and nasal structure may be attributed to the following
(A) Pax6 makes the optic vesicle competent and allows lens formation.
(B) The optic vesicle can induce any part of the head ectoderm to form the nasal and optic structures, due to presence of Pax6.
(C) Pax6 renders the head ectoderm competent to receive signals from optic vesicle.
(D) Apart from the optic vesicle, the head ectoderm may also be induced by BMP and FGF, so pax6 is not exclusive for lens formation.
Which of the above attributes are true?

QUESTION ID:11

The pattern of embryonic cleavage specific to a species is determined by two major parameters.
(A) The amount and distribution of yolk protein within the cytoplasm.
(B) The factors in the cytoplasm that influence the angle mitotic spindles and the timings of its formation.
Which of the following statements are true?

QUESTION ID:12

The fate of a cell or a tissue is specified when it is capable of differentiating autonomously on being placed in a neutral environment with respect to the developmental pathway. An embryo will show development pattern based on its type of specification: Based on the above facts it can be said that potency of a cell is:
(A) Equal to its normal fate in regulative development
(B) greater than its normal fate in regulative development
(C) equal to its normal fate in mosaic development
(D) greater than its normal fate in mosaic development
Which of the above statements are true?

QUESTION ID:13

In the context of the proximal-distal growth and differentiation of a tetrapod limb following experiments were visualized
(A) If the apical ectodermal ridge (AER) is removed at any time during the limb development, further development of distal limb skeletal elements ceases.
(B) If leg mesenchyme is placed directly beneath the wing AER, proximal hind limb structures develop at the end of the limb
(C) If an extra AER is grafted onto an existing limb bud, supernumerary structures are formed usually at the distal end of the limb.
(D) If leg mesenchyme is placed directly beneath the wing AER, proximal hind limb structures develop at the end of the limb
Which of the above experiments would show the possible interactions between the AER and the limb mesenchyme directly beneath it during limb development?

QUESTION ID:14

The following statements have been proposed for plant vegetative development:
(A) Lateral roots develop from epidermal cells.
(B) Shoots axillary meristem develops from shoot apical meristem during differentiation of leaf primordia.
(C) Root cap is made of dead cells.
(D) Lateral meristem and cylindrical meristem found in roots and shoots results in secondary growth.
Which of the above statements are true?

QUESTION ID:15

Red and far-red lights are perceived by plants through various photoreceptors including phytochromes. The activation of phytochromes is caused by?

QUESTION ID:16

Following are some facts regarding localization of photosynthetic supramolecular complexes on plastid lamellae:
A. PSII is preferentially localized on granal lamellae
B. ATP synthase and PSI is preferentially localized in stromal lamellae
C. PSI and PSII are located adjacent to each other in stromal lamellae
D. Cytchrome b6/f complex is not a membrane bound complex
Which of the following combinations of the above statements is true?

QUESTION ID:17

Phenyl ammonia lyase (PAL) and chalcone synthase (CHS) involved in biosynthesis of phenolic compound in plants. Following are some statements regarding the action of PAL and CHS:
A. Substrate for PAL is phenyl alanine and for CS is chalcone
B. PAL catalyze conversion of phenyl alanine to trans-cinnamic acid
C. PAL catalyze conversion of phenyl alanine to p-coumaric acid
D. Coumaryl CoA is converted to chalcone by chalcone synthase
Which of the following combinations of above statement is true?

QUESTION ID:18

Upon absorption of a photon, a chlorophyll molecule get converted to its excited state when the energy of photon is

QUESTION ID:19

Following are certain facts about the effect of abscisic acid (ABA) on the development and physiological effect of plants:
A. ABA promotes leaf senescence independent of ethylene.
B. ABA promotes shoot growth and inhibits root growth at low water potential.
C. ABA inhibits gibberellin induced enzyme production
D. Seed dormancy is controlled by ratio of ABA and gibberllin
Which one of the following combination of above statements is true?

QUESTION ID:20

While studying the primary effect of different abiotic stresses on plants, a researcher observed water potential reduction and cellular dehydration. Which of the following combination of abiotic stress may cause observed effect?

QUESTION ID:21

In an experiments, sperm removed from epididymis of a male mouse was added in a dish containing appropriate media and oocyte. No fertilization was seen. However, when sperm from epididymis were directly placed in uterus of an ovulated female, she became pregnant .These observation suggest that

QUESTION ID:22

Level of follicle stimulating hormone (FSH) during infancy and adulthood is the same but spermatogenesis is seen only during adulthood. mRNA levels coding for FSH receptor are also found to be the same in testis of both age groups.
Which of the following investigations will clarify this paradox a little more?

QUESTION ID:23

GnRH is secreted during infancy (0-6 month) and puberty onwards (4 years and above) in monkeys. However, i. v.injection of GnRH during pre-pubertal period (about 2 years of age) led to elevated LH and FSH in blood compared to untreated 2 years old monkey. This suggest that
(A) Hypothalamus is active during pre-pubertal period
(B) GnRH action on pituitary is age dependent
(C) Pituitary matures during adulthood
(D) Pituitary is active in all stages of development in monkeys
Which one of the following is true?

QUESTION ID:24

The stereocilia of auditory hair cells are arranged in rows but the height of stereocilia are not the same in all the rows. Though the height of stereocilia is the same within a particular row, the heights increase in subsequent rows. When the stereocilia of shorter rows are mechanically pushed toward the taller rows, the hair cells are depolarized but a push on opposite direction hyperpolarize them. The significance of this graded height of stereocilia is:
(A) Each row of stereocilia may be displaced independent of other rows in physiological conditions
(B) The tip of the taller stereocilia will show greater displacement as compared to shorter ones when all the rows are moving in same axis
(C) The hair cells will be depolarized or hyperpolarized in different grades when the axis of displacement is changed
(D) The taller stereocilia are involved with depolarization and shorter ones are responsible for hyperpolarization
Which of the following is correct?

QUESTION ID:25

A person suffering from thyrotoxocosis has extremely high level of thyroid hormone in blood. There is failure of feedback regulation in hypothalamic-pituitary-thyroid axis. The detailed blood investigation exhibited high level of the following:
A. Thyroid stimulating hormone (TSH)
B. Thyroid stimulating Immunoglobulin (TSI)
C. Thyroid releasing hormone
D. Parathyroid hormone

In your opinion, which one of the following is the reason for such thyrotoxicosis

QUESTION ID:26

A person has been suffering from night blindness. On consultation, the doctor advised person to eat carrots and/or cod fish oil. After some time having seen no improvement, doctor gave person vitamin A injection. Still no marked improvement was seen. The doctor mooted several suggestions indicating lack of the following enzymes for failure of treatment:
A. Retinol dehydrogenase
B. Retinal reducatase
C. Retinal isomerase
D. Retinal synthase
According to your opinion which is correct reason for night blindness in above case?

QUESTION ID:27

The rate of mutation in E. coli from lac- to lac+ are determined using medium containing lactose, as the only sole source of energy. The principle of spontaneity can be said to be violated if:

QUESTION ID:28

Three E. coli mutants were isolated which require compound ‘A’ for their growth. The compounds B, C and D are known to be involved in biosynthetic pathway to A. In order to determine pathway, the mutants were grown in a minimal medium supplemented with ONE OF THE COMPOUNDS, A TO
D. The results obtained are summarized below:

‘+’ = Growth on medium ‘0’ = No growth

Which of the following equation represents the biosynthetic pathway of A?

QUESTION ID:29

A cell undergoing meiosis produces four daughter cells, two of which are aneuploids, while two are haploid. This can occur due to:

QUESTION ID:30

When two independent pure lines of pea with white flowers are crossed, the F1 progeny has purple flowers. The F2 progeny obtained on selfing shows both pruple and white flower in a ratio of 9:7. The following conclusions were made
A. Two different genes are involved, mutation in which lead to formation of white flower.
B. These two genes show independent assortment
C. This is an example of complementary gene action
D. The is an example of duplicate genes
Which of the following conclusions are correct?

QUESTION ID:31

Following are four modes of inheritance

A. X-linked recessive

B. X-linked dominant

C. Autosomal recessive

D. Autosomal dominant
Which of the above modes of inheritance can explain the pedigree shown below? Which of the following modes can be represented by pedigree chart above?

QUESTION ID:32

Four different mutant lines showing similar phenotype were identified from a genetic screen. When genetic crosses amont these mutants were carried out, the first mutant was found to complement the second, third and fourth mutant lines. However, no other complementation groups do the four mutant lines belongs to?

QUESTION ID:33

Why lysogenic cycle is more beneficial to a virus than lytic cycle under certain circumstances?

QUESTION ID:34

Two auxotrophic strains of E. coli: A (met- bio- thr+ leu+ thi+) and B (met+ bio+ thr- leu- thi+) were incubated together for 18 hours in liquid medium and then ~108 cells were plated on minimal medium. Prototrophs were observed at frequency of 1 X 10-7 cells. This may have happened by process of genetic
recombination between two strains or by mutation of strains. Which of the following control experiment would help rule out the possibility of mutation?

QUESTION ID:35

According to fossil record, the earliest fossils of liverworts are found in late Devonian, of mosses in early cretaceous, and vascular plants in the later Silurian/early Devonian. Anthoceros (hornworts) fossils have not been recovered. Reading fossil recores we would say that vascular plants appeared first and then liverworts.

However phylogenetic relationship (shown in figure) suggest otherwise. It may be that
(A) evolutionary history can be read directly from fossil record
(B) The moss lineage goes back to at least early Silurian/early Devonian
(C) Fossil can only set a maximum age for a lineage
(D) Fossil can only sets a minimum age for a lineage
(E) the divergence between liverworts and rest of land plants goes back to at least early Ordovician
Which of the following statements is correct?
 

QUESTION ID:36

Which of the following hypothesis best explains the occurrence of Himalayan floral element in Western Ghats of  India ?

QUESTION ID:37

In which of the following classes of vertebrates there are group of animals without limbs?

QUESTION ID:38

 Identify ‘a’, ‘b’ and ‘c’ in the figure
 

QUESTION ID:39

The schematic section given below of an animal indicates that the animal is

Based on above diagram the organism is
 

QUESTION ID:40

A researcher collected information from four forest using sensors to assess their green cover. Observed average spectral values from each of the forest are given in the table below:
The forest cover in the order of highest to lowest is

QUESTION ID:41

In Lotka and Voltera’s two species competition model:

Where N represents population size, r growth rate and K maximum carrying capacity for species 1 and 2. The interspecific competition coefficient α12 <1will mean:
 

QUESTION ID:42

While studying the diversity of 3 communities, 5 species and 50 individuals were recorded from each community. The number of individuals under each species was listed as mentioned in the following Table. In which of the following community Pielou’s Evenness index (e) will be 1?

QUESTION ID:43

At a given time, the age class distribution of a population was as shown in figure: Which of the following can be inferred from the figure?
 

QUESTION ID:44

Average annual precipitation and temperature are two important determinants of world’s major biomes. Which of the following combinations are correct?

QUESTION ID:45

Which of the following is a prediction of neutral theory of molecular evolution that is supported by data?

QUESTION ID:46

During line-transect sampling of two solitary species of ground mammals the following observations were made:

Which of the following can be inferred from the data?
 

QUESTION ID:47

In hymenoptera insects, males are haploid and females are diploid. All fertilized eggs give rise to female and unfertilized eggs give rise to males. As a result, if a female mates with a single male, the females in progeny are related to 75 %. But if the mother had mated with males, the mean genetic relatedness of female progeny is correctly represented by

QUESTION ID:48

There are ‘n’ numbers of alleles at a given locus in a diploid population. The proportion of all homozygotes in the population
(A) All alleles are equal abundant
(B) All alleles are not in equal abundant

QUESTION ID:49

A species has the following population characteristics:
A. reduction in population size > 90 % over last 10 years or 3 generations
B. Geographical range: Extent of occurrence <100 Km2 and Area of occupancy: <10km2
C. Population size less than 50 mature individuals
D. Probability of extinction in wild at least 50 % within the next 10 years or 3 generations
To which of the following categories the species will be assigned according to IUCN categorization of threatened species (version 3.1)?

QUESTION ID:50

Biologist randomly sampled about 300 insects from a newly found island. The distribution of their abundance in the sample was un the figure given below.
Which of the following can be correctly inferred from the graph?
 

QUESTION ID:51

Northern elephant seal had been reduced to about 20 in 1800s. Biologist studied variation in protein in the species. They found no genetic differences in the protein among individuals. This lack of variation is due to

QUESTION ID:52

Which of the following curve correctly represents the antibiotic production by Streptomyces species?

QUESTION ID:53

Stem cells are widely used for their regenerative property and capacity to differentiate into different lineages. A person with a damaged liver approaches a stem cell therapist. Which of the following therapeutic strategy would be safest?

QUESTION ID:54

The Scatter plot of growth rate and growth yield for 100 random environment isolates of bacteria is shown below

Which of the following can be inferred from data ?
 

QUESTION ID:55

In Radio Immuno Assay (RIA) for glucocorticoid hormone, glucocorticoid (tritiated) is added to RIA cocktail. When the amount of bound hormone was measured no radioactive counts were observed. The following possible explanation(s) were proposed:
A. The radioactive hormone was insufficient
B. The radioactive tag to the hormone completely dissociated during storage
C. Antibody was not added to the cocktail
D. The specific activity of tritiumwas low
Choose the correct options(s):

QUESTION ID:56

Four different receptors viz, A, B, C and D bind to same ligand ‘X’. In order to determine when receptors has the highest ligand binding affinity following experiment was carried out. Cells were transfected with green fluorescent protein (GFP)-tagged receptors (A, B, C and D) individually, then incubated with red fluorescent protein (RFP) tagged ligand ‘X’ and subjected to FACS. Following are the results
Which receptor has highest binding affinity for ligand ‘X’?
 

QUESTION ID:57

If one wishes to design a microarray chip for whole genome expression analysis of an eukaryotic system, which region of the gene should be preferred for selection of unique target sequences?

QUESTION ID:58

For the generation of transgenic plant in crop improvement, one important regulatory gene ‘X’ was overexpressed in a crop plant. Out of 30 transgenic rice plants generated, 22 showed high levels of gene ‘X’ expression. However, rest 8 lines displayed low level of expression. One explanation of such observation may be:

QUESTION ID:59

QUESTION ID:60

 A protein contains 2 Trp and 4 Tyr residues. The molecular mass of the protein is 17000 D and that of Trp and Tyr are 204 and 180 D respectively. Values of E1%1cm, the absorption coefficient of 1% (g/v) solutions of Trp and Tyr in 1-cm cell at 280 nm, are 269.60 and 83.33, respectively. The absorption of 1 mg/ml protein solution in 1 cm-cell at 280 nm will be:

QUESTION ID:61

Double stranded DNA replicates in a semi –conservative manner. In an in vitro DNA synthesis reaction , dideoxy CTP and , dideoxy CMP were individually added in excess (in separate reaction tubes) in addition to dNTPs and other necessary reagents. Rate of DNA Synthesis was measured by
incorporation of 3H-thymidine. The four graphs drawn below represent the rate of DNA synthesis in two separate reaction tubes.
Which of the following graphs represents the expected data?