Previous Year Questions

QUESTION ID:2

Cholera toxin activates the chloride channel in the epithelial cells of intestine leading to loss of Cl^-, and consequent loss of water leading to dehydration. Successful oral rehydration therapy involves supplementing water with glucose and salt and not just salt. This is 

QUESTION ID:3

Given below are a few statements about vesicular transport. 

A. Clathrin-mediated endocytosis requires the recruitment of adaptors to the cytosolic face of the plasma membrane.

B. The low-pH environment of early endosomes leads to the dissociation of cargo from its receptor, allowing for the recycling of receptors to the plasma membrane.

C. The late endosomes, which mature into the lysosomes, are directly involved in the recycling of synaptic vesicle proteins in neurons.

D. The multivesicular body pathway involves the formation of intraluminal vesicles, which sort cargo for degradation in the lysosomes.

Which one of the following options has all correct statements about endocytosis? 

QUESTION ID:4

Given below are a few statements. 

A. Codominant molecular markers ______(i)______ be used for identification of heterozygotes.

B. Genome wide association studies (GWAS) ______(ii)______ be performed on germplasm with high genetic diversity.

C. An F2 mapping population ______(iii)______ be used as an immortal population for genetic mapping studies in plants.

D. Bulk segregant analysis (BSA) ______(iv)______ be used for mapping of monogenic qualitative traits.

Which one of the following options represents the correct sequence of terms to fill in the blanks in the above statements so that all the statements are true?

QUESTION ID:5

In a typical experiment, 15 mL of an aqueous solution containing an unknown quantity of acetylcholine had a pH of 7.65. When the solution is incubated with acetylcholinesterase, the pH of the solution decreased to 6.87. Assuming that there was no buffer in the reaction mixture, determine the number of moles of acetylcholine in the 15 mL solution.

QUESTION ID:6

Given below are four metabolic intermediates (i-iv) listed against amino acids (A-E):

A. i - serine, glycine, cysteine

B. iv - alanine, valine, leucine

C. iii - glutamate, glutamine, proline

D. ii - methionine, threonine, lysine

E. i - histidine

Which one of the following options correctly pairs the metabolic intermediates with their corresponding amino acid end product(s)?

QUESTION ID:7

Following statements are made with respect to polar auxin transport in plants.

A. It proceeds via symplast.

B. Its velocity is faster than the phloem translocation rates.

C. It is specific for active auxins, both natural and synthetic.

D.    It is mediated by protein carriers on the plasma membrane.

Which one of the following options represents the combination of all correct statements? 

QUESTION ID:8

The phylogeny given below depicts the evolutionary relationships and branch lengths of species found in three spider communities, X, Y, and Z, along with a table showing their absence (0) and presence (1) in these communities.

Which one of the following options gives the correct values of phylogenetic diversity for these communities?

QUESTION ID:9

In an experiment, while screening for loss-of-function mutants, a student found a mutation in the gene encoding caspase-9 in the intrinsic pathway of apoptosis. The following are the possible consequences for this mutant cell: 

A. Loss of mitochondrial membrane potential and release of cytochrome C.

B. Reduced formation of the apoptosome and defective initiation of apoptosis.

C. Inability to activate the death receptors.

D. Become resistant to UV irradiation-induced cell death.

Which one of the following options represents all correct statements?

QUESTION ID:10

Populations of two species (A and B) follow logistic growth. The parameter values for the logistic growth equation are given in the table below. 

Select the option that correctly gives the population growth rate at N = 100 for both species.

QUESTION ID:11

QUESTION ID:12

Angiotensin converting enzyme (ACE) converts angiotensin I into angiotensin II. ACE inhibitors should not be given to a person with severe loss of blood because:

A. these will increase renal tubular K⁺ excretion.

B. these will relax smooth muscles in the arteries.

C. these will reduce aldosterone secretion and thereby prevent water retention.

D. these will decrease renal tubular NaCl and water excretion.

Which one of the following options represents the combination of correct reasons?

QUESTION ID:13

Consider a predator that can forage on two prey types, where Prey₁ is the more profitable prey and Prey₂ is the less profitable prey. While searching for Prey₁, if it encounters Prey₂, the decision to capture Prey₂ or ignore it and continue to search for Prey₁ is given by the predictions of the Optimal Foraging Theory (OFT). The table below gives various parameters that may be used as per OFT by the predator in making this foraging decision. 

Which one of the following statements predicts correctly when the predator should eat Prey₂, given the conditions above?

QUESTION ID:14

QUESTION ID:15

QUESTION ID:16

QUESTION ID:17

QUESTION ID:18

QUESTION ID:19

Match the insects (Column X) to the insect orders (Column Y)

Select the option that correctly matches column X with column Y.

QUESTION ID:20

The following statements are made regarding root-knot nematode infection in plants.

A. Chemical signals released by the plant roots can induce hatching of the juvenile nematodes.

B. Mitosis coupled with cytokinesis and DNA endoreduplication is induced during root-knot nematode infection.

C. Nematodes form syncytial feeding structures by recruiting plant cells.

D. Nematode infections suppress cortical cell growth in plants.

Which one of the following options represents the combination of all correct statements?

QUESTION ID:21

Wnt/β-catenin signaling plays essential roles during development. The following statements are made about the Wnt/β-catenin signaling pathway:

A. In the absence of Wnt ligands, β-catenin is phosphorylated by the APC/Axin/GSK-3β complex, leading to its degradation.

B. The β-catenin/TCF complex acts as a repressor of gene expression upon activation of Wnt signaling.

C. The Wnt/β-catenin pathway is initiated by binding of Wnt ligands to receptor tyrosine kinases (RTKs).

D. β-catenin is involved in both cell-to-cell adhesion and transcriptional regulation.

Which one of the following options represents all correct statements?

QUESTION ID:22

The figure below shows the genes (a, b, c, d, f, I, m, n) that are expressed in cell types 1, 2, and 3 because of the concentration of morphogen signaling received by these cells.

Which one of the following statements is correct about the pattern of gene expression induced by the morphogen? The transcription factor activated by the morphogen has: 

QUESTION ID:23

To study different DNA double-strand break (DSB) repair pathways, a construct is developed that contains a neomycin selectable marker gene flanked by two inactive GFP genes: the first one is inactivated by the insertion of an I-Scel recognition sequence, and the other one has a 99 bp deletion at the 5 end of the gene. The induction of the I-Scel endonuclease will create a DSB in the first GFP sequence.

The following expected outcomes have been proposed:

A. If the DSB is repaired by the gene conversion (GC) pathway, cells will be GFP-positive and neomycin-resistant.

B. If the DSB is repaired by the GC pathway, cells will be GFP-positive but neomycin-sensitive.

C. If the DSB is repaired by the single-strand annealing (SSA) pathway, cells will be GFP-positive and neomycin resistant.

D. If the DSB is repaired by the non-homologous end joining (NHEJ) pathway, cells will be GFP-negative and neomycin resistant.

Which one of the following options represents the combination of all correct statements? 

QUESTION ID:24

The circular dichroism spectra for near-UV and far-UV regions of a polypeptide chain are given below.

Which one of the following options represents a correct inference about the polypeptide fold based on the above data? 

QUESTION ID:25

ΔG^o of a reaction shows the following temperature dependence.

What is the expected dependence of K_eq of the reaction on the temperature, where C is a temperature-independent constant?

QUESTION ID:26

Which one of the following scenarios is likely to produce the highest beta diversity for tree species in a forested landscape? 

QUESTION ID:27

A student performed an ELISA to detect anti-ovalbumin IgG in a serum sample. The experiment involved the following sequential steps: coating plates with ovalbumin, blocking with BSA, adding serum sample, adding anti-mouse-lgG-HRP, adding H₂O₂ + o-Phenylenediamine dihydrochloride (OPD), and adding H₂SO₄. The student made the following statements:

A. If the plates are not blocked with BSA, the specificity of the assay decreases.

B. If the plates are not washed between addition of serum sample and addition of anti-mouse IgG-HRP, the sensitivity of the assay decreases.

C. If the plates are not washed between addition of anti-mouse IgG-HRP and addition of H₂O₂ + OPD, the specificity of the assay decreases.

D. OPD is the substrate for the enzyme.

E. Without H₂SO₄, no colour is developed.

Which one of the following options represents the combination of all correct statements? 

QUESTION ID:28

Match the following ribose sugar pucker in nucleic acids (labeled A, B, C, D) with their corresponding conformational states. The black circle denotes the base of the nucleotide.

QUESTION ID:29

T cell precursors that exit the bone marrow undergo positive and negative selection in the thymus before emerging as mature T cells. These processes are controlled by cellular interactions of the thymocyte with stromal cells in the thymus. The following statements are made regarding the selection process:

A. The selection process involves negative selection of auto-reactive cells in the cortex followed by their migration to the medulla.

B. The selection process relies on the transcription factor 'Aire'.

C. The selection process can lead to the generation of CD4 cells that can interact with dendritic cells (DCs) as well as B cells.

D. The selection process can lead to the generation of regulatory CD4 T cells.

Which one of the following options represents the combination of all correct answers?

QUESTION ID:30

Some of the following statements describe nomenclature rules in the International Code of Zoological Nomenclature (ICZN).

A. If the generic name is of masculine gender, the species name should be of feminine gender.

B. A name is to be rejected if it is a tautonym or inappropriately describes a taxon's character.

C. The name of an animal taxon cannot be rejected because it is identical with the name of another taxon which is not an animal.

D. Even if the taxon concerned is no longer classified as an animal, its name remains available.

Select the option that includes all statements representing currently accepted nomenclature rules of the ICZN. 

QUESTION ID:31

The following statements suggest the physiological characteristics of the dead space in respiratory system, alveolar ventilation (the amount of air reaching alveoli per minute) and respiratory minute volume (RMV) in healthy individuals.

A. The alveolar ventilation is less than RMV.

B. The anatomic dead space can be estimated by the body weight of the individual.

C. At rest, the anatomic dead space and physiological dead space are identical.

D. The alveolar ventilation is higher in rapid shallow breathing than that of the slow deep breathing at the same RMV.

Which one of the following options represents the combination of correct statements?

QUESTION ID:32

The descending phase of the nerve action potential is caused by:

A. delayed opening of voltage-gated K⁺ ion channels.

B. rapid opening of voltage-gated Na⁺ ion channels.

C. closing of voltage-gated Na⁺ ion channels.

D. leaky K⁺ ion channels. 

Which one of the following options represents the combination of correct statements?

QUESTION ID:33

The table below lists the food reserves (Column X) found in different algal groups (Column Y).

Select the option that correctly matches column X with column Y. 

QUESTION ID:34

A purified 150 kDa species obtained from a gel filtration column was run on a 2- dimensional SDS-PAGE as shown below:

What is the likely form of the 150 kDa species from this observation?

QUESTION ID:35

After synchronizing mammalian cells in culture with a double thymidine block (cell cycle duration of 24h), cells are released into fresh medium. After 6h, cells are split into 4 sets and each is treated with a) nothing, b) proteasome inhibitor, c) myosin II inhibitor, d) nocodazole.

From the options given below, choose the one that has the most likely outcome of the experiment.

QUESTION ID:36

The following table shows a list of migratory birds coming to India (Column X) and the region from where they migrate (Column Y).

Which one of the following options represents all correct matches between Column X and Column Y?

QUESTION ID:37

Based on homology, a protein, CG2024, functions as a homotetramer. The function of each unit within the tetramer is essential for its catalytic activity. CG2024 protein has three domains. Domain 'a' is essential for tetramerization, domain 'b' is essential for catalytic activity and domain 'c' does not contribute to CG2024 function at all. Three mutations, a*, b* and c* in the 'a', 'b' and 'c' domains of CG2024, respectively, have been identified. The a* and b* disrupt the function of their respective domains.

Based on this information, which one of the following options correctly describes the nature of mutations a*, b* and c* (in the same order)?

QUESTION ID:38

The following statements are made about the involvement of the type III protein secretion system (T3SS) during bacterial pathogenesis in plants and animals.

A. It involves a protein complex that spans both the inner and outer bacterial membranes.

B. T3SS mostly secretes Avr effector proteins directly into plant apoplast.

C. The genes encoding conserved components of the T3SS of plant and animal pathogenic bacteria are referred to as Hrp (hypersensitive response and pathogenicity cluster).

D. Once Avr effectors are delivered inside the plant cell, Hrp proteins are not needed for the activation of the defence response.

Which one of the following options represents the combination of all correct statements? 

QUESTION ID:39

The interconversion of fructose 6-phosphate to fructose 1,6-bisphosphate is a critical step in central metabolism in plants. Followings are certain statements regarding this interconversion.

A. Phosphofructokinase catalyzes the C6 phosphorylation of fructose 6- phosphate.

B. Plastid phosphofructokinase is activated by Pi while cytosolic phosphofructokinase is activated by phosphenolpyruvate.

C. Cytosolic fructose1,6-bisphosphatase is strongly inhibited by fructose 2,6- bisphosphate.

D. Pyrophosphate-dependent phosphofructokinase catalyzes a reversible reaction of interconversion of fructose 6-phosphate to fructose 1,6- bisphosphate.

Which one of the following options is a combination of all correct statements?

QUESTION ID:40

The lipid composition of the two monolayers of the plasma membrane is quite different. This lipid asymmetry is functionally relevant, especially in converting extracellular signals into intracellular ones. Given below are a few membrane lipids:

A. Phosphatidylserine

B. Phosphatidylinositol 4-phosphate

C. Phosphatidylcholine

D. Sphingomyelin

Choose the option that correctly defines all the lipids involved in signaling and are restricted to the cytosolic face of the plasma membrane.

QUESTION ID:41

Breast cancer stem cells may be identified by analyzing the CD24/CD44 phenotype of a breast tumor. CD24/CD44 stained cells were analyzed by flow cytometry and the analysis is shown below.

Further analyses of the sorted cells from different quadrants (Q1 to Q4) by immunoblotting revealed the following results. The dotted lines represent lanes with negligible signal.

Based on the above results, which phenotype is associated with the maximum number of breast cancer stem cells?

QUESTION ID:42

A mutation in a plant gene is female gametophyte lethal. This mutant allele can be normally transmitted through pollen. However, when transmitted through egg, the embryos abort, resulting in inviable seeds irrespective of the male allele. A student harvested the seeds from a heterozygous mutant plant and grew a total of 100 plants. What is the expected number of homozygous plants in this population?

QUESTION ID:43

Normal yeast cells grow at 42°C. Five yeast haploid strains, with independent alleles of YFG1 having impaired cell growth at 42°C, were isolated and labeled as yfg1ts1 to yfg1ts5. A haploid (yfg1ts1) carrying a spontaneously generated mutation (sup1) at an independent locus was isolated, which can grow at 42°C. Using pairwise crossing, sup1 was introduced into strains carrying yfg1ts2 to yfg1ts5 alleles. All these haploids grew at 42°C.

Based on this data, the following statements were made to describe the Sup1-Yfg1 molecular/genetic interaction.

A. Sup1 codes for a protein which, when over-expressed, stabilized mutant yfg1ts proteins.

B.  Sup1 codes for a protein that physically interacts with Yfg1 protein.

C. Sup1 protein upregulates an alternate pathway.

D. Sup1 is a nonsense suppressor that restores protein translation in cells carrying yfg1ts allele.

Which one of the following options represents the combination of all correct statements?

QUESTION ID:44

A molecule absorbs light at 'X' nm wavelength and emits light as fluorescence at 'Y nm wavelength. Typically, there is a shift in the wavelength (Y>X). E is the energy transferred to the solvent during reorganization of the excited state, 'h' is the Planck's constant, and 'c' is the speed of light.

E is equal to:

QUESTION ID:45

Consider the following statements on patterns in globalbiogeography. 

A. The endemicity of terrestrial mammal families in biogeographic realms is greater than plant families.

B. There are fewer mammalian fruit eaters, omnivores, and carnivore species in Australia compared to other biogeographic realms.

C. Major diversification of modern mammals started only 65-55 million years ago.

D. On an average, plant species have dispersed much better than mammalian species across biogeographic realms.

Which one of the options given below contains the correct set of True/False statements, based on well-established patterns in global biogeography?

QUESTION ID:46

In sesame, the seed coat color is of two types: white or brown. True breeding whiteand brown-seeded plants were reciprocally crossed and the results are given below.

Which one of the following types of inheritance explains the depicted transmission of seed color in sesame?

QUESTION ID:47

The figure below depicts the allosteric regulation in the biosynthesis of three aromatic amino acids- Phe, Tyr and Trp, acting at four major steps catalyzed by enzymes, CM, AS, ADT and ADH. The feedback regulation and relaxation of enzyme activities by the end-product amino acids are marked.

Following assumptions are made regarding the pool of aromatic amino acids in the feedback-insensitive mutants of these allosteric enzymes.

A. The feedback-insensitive mutant of CM will show higher pool of Phe and Tyr.

B. The feedback-insensitive mutant of AS will increase only Trp pool.

C. The feedback-insensitive mutant of AS will show higher pool of Trp, Phe and Tyr.

D. In feedback-insensitive mutant of ADH, only Tyr pool is decreased.

E. In feedback-insensitive mutant of ADH, both Tyr and Phe pools are increased transiently.

Which one of the following options represents a combination of all correct assumptions?

QUESTION ID:48

In the classical metapopulation model articulated by Richard Levins (1969, 1970), the metapopulation is considered to be a collection of subpopulations occupying different patches. In this model, we consider the following conditions:

A. Individual subpopulations have realistic chances of both extinction and recolonization.

B. The dynamics of the various subpopulations should be largely independent.

C. Recolonization of a patch after extinction is mainly through dispersal from the mainland patch.

D. Population dynamics in the patches of a metapopulation should be highly synchronous.

Which one of the options given below includes conditions that should be met for a population to be considered a metapopulation? 

QUESTION ID:49

The graph below shows the plot of 1/v vs 1/[S] for an enzymatic reaction, with the solid and dashed lines representing the reactions without and with an inhibitor, respectively. The concentration of the inhibitor is 1 µM.

Which one of the following will be the K_l of the inhibitor?

QUESTION ID:50

The following statements were made about the alternative pathway of Complement activation in the immune system:

A. The pathway is initiated when antibodies bind to pathogen.

B. The pathway is initiated by spontaneous hydrolysis of serum Complement.

C. The pathway uses the same C3- and C5-convertases as the lectin pathway.

D. The pathway can be initiated by properdin and thrombin.

Which one of the following options represents the combination of all correct statements? 

QUESTION ID:51

An ecologist calculates the Shannon-Wiener diversity index for an ecosystem with high species diversity. Which one of the following statements about this diversity index is INCORRECT?

QUESTION ID:52

Presence of E-cadherin activates the Hippo pathway in the inner cell mass (ICM). Experimentally eliminating E-cadherin disrupts both apicobasal polarity and specification of the ICM and trophoectoderm lineages. Which one of the following schemes leads to pluripotency?

QUESTION ID:53

With reference to the origin of multicellularity in different life forms, which one of the following statements is INCORRECT?

QUESTION ID:54

A researcher studying the mating systems in birds (operational sex ratio 1:1) uses the number of successful matings as a measure of male reproductive fitness and female reproductive fitness, as depicted in the figure below.

Which one of the following options correctly matches P and Q with the correct sex for different mating systems? 

QUESTION ID:55

The mechanisms of action of calcitropic hormones are important for understanding the molecular basis of disease states related to calcium homeostasis.

A. Calcium binding (transport) protein (CaBP) enhances the movement of calcium from the brush border into the cytoplasm.

B. Receptors for calcitonin are present in the osteoclasts where they increase CAMP production.

C. Parathormone essentially works independently to mobilize bone mineral, and never in concert with vitamin D.

D. The major calcitropic hormone, calcitriol, regulates intestinal calcium absorption.

Which one of the following options is INCORRECT in maintaining calcium homeostasis?