Previous Year Questions

QUESTION ID:2

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:3

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:4

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:5

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:6

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:7

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:8

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:9

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:10

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:11

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:12

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:13

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

QUESTION ID:14

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:15

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?