Two steroid hormone receptors X and Y both contain a ligand binding domain and a DNA binding domain. Using recombinant DNA technology, a modified hybrid receptor H is prepared such that it contains the ligand binding domain of X and DNA binding domain of Y. Three sets of cells over-expressing receptors X, Y and H were then treated separately either with hormone X or with hormone Y. Asuming that there is no cross-reactivity, which one of the following graphs best represent the receptor-ligand binding in each case?Cells ever expressing receptor

A protein X is kept inactive state in cytosol as complexed with protein Y. Under certain stress stimuli, Y gets phosphorylated resulting in its proteasomal degradation. X becomes free, translocates to the nucleus and results in the transcription of a gene which causes cell death by apoptosis. Stress stimuli were given to the following four different cases :
Case A : Protein Y has a mutation such that phosphorylation leading to proteasomal degradation does not occur.
Case B : Cells are transfected with a gene which encodes for a protein L that inhibits the translocation of protein Y to the nucleus. 
Case C : Cells are transfected only with empty vector used to transfect the gene for protein L
Case D : Cells are treated with Z-VAD-FMK, a broad spectrum caspase inhibitor
Which of the following graphs best describes the apoptotic state of the cells in the above cases? Y-axis represents % apoptotic cells.

In animals, four separates families of cell-cell adhesion proteins are listed in Column A and their functional characteristics are given in Colun
.
Which one of the following is the correct combination?

A student treated cancer cells with an anticancer drug and performed western blot analysis. Which one of the following blots is the best representation of untreated control (C) and treated (T) samples?

Which one of the following statements regarding B cell receptor (BCR)
and T cell receptor (TCR) is NOT true?

In case of amphibians, the dorsal cells and their derivatives are called as “Spemann-Mangold. organizer”. Following statements related to the “organizer” were made:
1. It induces the host’s ventral tissues to change their fates to form a neural tube and dorsal mesodermal tissues.
2. It cannot organize the host and donor tissues into a secondary embryo.
3. It does not have the ability to self-differentiate into dorsal mesoderm
4. It has the ability to initiate the movements of gastrulation.
5. Both b-catenin & Chordin are produced by the organizer.
 Which of the above statements are correct?  

Driesch performed the famous “pressure plate” experiments involving intricate recombination with an 8-celled sea urchin embryo. This procedure reshuffled the nuclei that normally would have been in the region destined to form endoderm into the presumptive ectoderm region. If segregation of nuclear determinants had occurred, resulting embryo should have been disordered. However, Driesch obtained normal larvae form these embryos. The possible interpretations regarding the 8-celled sea urchinembryo are:
1. The prospective potency of an isolated blastomere is greater than its actual prospective fate.
2. The prospective potency and prospective fate of blastomere were identical.
3. Sea-urchin embryo is a “harmoniously equipotential system” because all of its potentially independent parts interacted together to form single embryo.
4. Regulative development occurs where location of a cell in the embryo determines its fate.
Which of the above interpretation(s) is/are true?

Consider the following events which occur during fertilization of sea urchin eggs.
1. Resact/Speract are peptides released from the egg jelly and help in sperm attraction.
2. Bindin, an acrosomal protein interacts in a species-specific manner, with eggs.
3. A “respiratory burst” occurs during cross-linking of the fertilization envelope, where a calcium-dependent increase in oxygen level is observed.
4. IP3, which is formed at the site of sperm entry, sequesters calcium leading to cortical granule exocytosis.
Which of the above statement(s) is NOT true?

Following statements were given regarding the decisions taken during the development of mammalian embryos :
1. The pluripotency of the inner cell mass (ICM) is maintained by a core of three transcription factors, Oct 4, Sox 2 and Nanog.
2. Prior to blastocyst formation each blastomere expresses both Cdx 2 and the Oct 4 transcription factors and appears to be capable of becoming either ICM or
trophoblast.
3. Both ICM and trophoblast cells-synthesize transcription factors Cdx 2.
4. Oct 4 activates Cdx 2 expression enabling some cells to become trophoblast and other cells to become ICM.
Which of the above statement are true?

Apoptosis during early development is essential for proper formation of different structures. In C. elegans, apoptosis is accentuated by ced-3 and ced-4 genes, which in turn are negatively regulated by ced-9 and eventually EGL-1. When compared to mammals, functionally similar homologues has been identified. Accordingly, which one of the following statements is NOT correct?

Individual and overlapping expression of homoeotic genes in adjacent whorls of a flower determine the pattern of floral organ development. In an Arabidopsis mutant, floral organs are distributed as follows:
 Whorl 1 (outer most) - carpel
Whorl 2 - stamens
Whorl 3 - stamens
Whorl 4 (inner most) - carpel
Loss of function mutation in which one of the following genes would have caused the above pattern of floral organ development? 

Phytochrome-mediated control of photo-morphogenesis is linked to many other gene functions. The following statements are made on the mechanism of phytochrome action:
1. Phytochrome function requires COP1, an E3 ubiquitin ligase that brings about protein degradation.
2. COP1 is slowly exported from the nucleus to the cytoplasm in the presence of light.
3. HY5 is targeted by COP1 for degradation in the presence of light.
4. HY5 is a transcription factor involved in photomorphogenetic response.
Which one of the following combinations is correct?

The C4 carbon cycle is a CO2 concentrating mechanism evolved to reduce photorespiration. The following are stated as important features of the C4 pathway :
1. The leaves of C4 plants have Kranz anatomy that distinguishes mesophyll and bundle sheath cells.
2. In the peripheral mesophyll cells, atmospheric CO2, is fixed by phos-phoenol pyruvate carboxylase yielding a four-carbon acid
3. In the inner layer of mesophyll, NAD-malic enzyme decarboxylates four-carbon acid and releases CO2.
4. CO2, is again re-fixed though Calvin cycle in the bundle sheath cells.
Which one of the following combinations is correct?

Read the following statements related to plant pathogen interaction :
1. Systemic acquired resistance is observed following infection by compatible pathogen.
2. Induce systemic resistance is activated following infection by
compatible pathogen.
3. A bacterial infection can induce effector triggered immunity (ETI) leading to hypersensitive response locally.
4. NPR1 monomers that are released in cytosol due to salicylic acid accumulation is rapidly translocated to nucleus.
Which combination of above statements is correct?

Given below are statements describing various features of solute transport and photo-assimilate translocation in plants:
1. Apoplastic phloem loading of sucrose happens between cells with no plasmo-desmatal connections.
2. Growing vegetative sinks (e.g., young leaves and roots) usually undergo symplastic phloem unloading.
3. Movement of water between the phloem and xylem occurs only at the source and sink regions.
4. Symplastic loading of sugars into the phloem occurs in the absences of plasmodesmatal connections.
Select the option that gives combination of correct statements :

Given below are names’of phytohormones in column I and their associated features/ effects/ function in column II
.
Select the correct set of combinations from the options given below :

If in a blood transfusion, type A donor blood is given to a recipient having type B blood, the red blood cells (RBCs) of donor blood would agglutinate but the recipients RBCs would be least affected. These observations can be explained in the following statements :
1. Agglutinins in recipient’s plasma caused agglutination by binding with type A agglutinogens.
2. The agglutinins of donor blood was diluted in recipient’s plasma resulting in low agglutination.
3. Low titre of anti-A agglutinins is the cause of low agglutinations of recipient’s RBCs.
4. High agglutination of donor RBCs is the outcome of high titre of anti-B agglutinins
Which of the above statement(s) is/are INCORRECT?

The arterial pressure usually rises and falls 4 to 6 mm Hg in a wave like manner causing “respiratory waves”. The probable mechanism of these waves has beenproposed in the following statements:
1. The more negative intrathoracic pressure during inspiration reduces the quantity of blood returning to the left side of the heart causing decreased cardiac output.
2. The changes of intrathoracic pressure during respiration can excite vascular and atrial stretch receptors which affect heart and blood vessels.
3. The activity of medullary respiratory centers can influence the vasomotor center.
4. The “respiratory waves” are outcome of the oscillation of the central nervous system ischemic pressure control mechanism.
Which of the above statement(s) is/are NOT appropriate?

The uptake of nitrous oxide (N₂O) and carbon monoxide (CO) in the blood of lung alveolar capillary relative to their partial pressure and the transit time of red blood cell in capillary is shown in the figure below :

The reasons for difference in the pattern of alveolar gas exchange of N₂O and CO have been proposed in the following statements :
1. N₂O does not chemically combine with proteins in blood but equilibrate rapidly between alveolar gas and blood.
2. CO has high solubility in blood
3. CO has high solubility in the alveolar capillary membrane
4. The dispersion of N2O between alveolar gas and blood is considered as diffusion limited.
Which of the above statement(s) is/are INCORRECT?

External pressure given on a mixed nerve causes loss of touch sensation while pain sensation remains relatively intact. On the other hand, application of local anaesthetics on the same nerve, induces loss of pain sensation keeping touch sensation least affected. These observations can be explained by the following statements :
1. External pressure causes loss of conduction of impulses in small diameter sensory nerve fibres.
2. Local anaesthetics depress the conduction of impulses in large diameter sensory nerve fibres.
3. Touch-induced impulses are carried by fibre Type A
4. Fibre type C is responsible for pain sensation
Which of the above statement(s) is/are INCORRECT?

The probable effects of lesion of left optic tract on the vision of a human subject are given below. Identify the correct statement. 

The following diagram represents steroidogenic pathway in the Zona Glomerulosa of the adrenal cortex :

What do A, B and C represent, respectively? 

Inversions are considered as cross-over suppressors because :

A pair of alleles govern seed size in a crop plant. ‘B’ allele responsible for bold seed is dominant over ‘b’ allele controlling small seed. An experiment was carried out to test if an identified dominant DNA marker (5kb band) is linked to alleles controlling seed size. A plant heterozygous for the marker and the alleles was crossed to a small seeded plant lacking the 5kb band. 100 progeny obtained from the cross were analysed for the presence and absence of the DNA marker. The result are tabulated below :

Based on the above observations which one of the following conclusions is correct?

Three met– E. coli mutant strains were isolated. To study the nature of mutation these mutant strains were treated with mutagens EMS or proflavins and scored for revertants. The results obtained are summarized below :
  
(+ stands for revertants of the original mutants and – stands for no revertants obtained).Based on the above and the typical mutagenic effects of EMS and proflavin, what was the nature of the original mutation in each strain?

The following scheme represents deletions (1-4) in the rll locus of phage T4 from common reference point :
Deletion 1    _______
Deletion 2    ___________
Deletion 3     ________________
Deletion 4    ______________________
(The bars represent the extent of deletion in each case)
Four point mutations (a) to (d) are tested against four deletions for their ability (+) or inability (–) to give wild type (rII+) recombinants. The results are summarized below :

Based on the above the predicted order of the point mutations is :

The following pedigree shows the inheritance pattern of a trait.

From the following select the possible mode of inheritance and the probability that the daughter in generation III will show the trait.

Interrupted mating experiments were performed using three different Hfr strains (1-3). The three strains have different combinations ofselectable markers. The time of entry for markers for each strain is shown is shown in the table below.

Peripatus is an interesting living animal having unjointed legs,nephridia, haemocoel, trachea, dorsal tubular heart, claws, jaws, continuous
muscle layers in body wall.This is considered as a connecting link between : 

The following schematic diagram represents secondary growth in angiosperms.

Based on above scheme which of the following options represent the correct identity of the cambia labelled as A, B, C and D.

The table below lists the major fungal groups and their characteristics :

Which one of the following options represents the appropriate match between the fungal group and their characteristics?

As a biologist, you want to classify three taxa, A, B and C. You have the information on three traits, p, q and r The trait that is ancestral is counted ‘0’ and the trait that is derived is counted as ‘1’. The distribution of traits found in three taxa is given below :

Based on the above table, the following cladograms were drawn :

Based on trait distribution and the principle of parsimony select the correct option :

Given below are statements pertaining to organisms belonging to three domains of life. Identify the INCORRECT statement.

You observed that two species of barnacles, species 1 and species 2, occupy upper and lower strata of intertidal rocks, respectively. Only when species 2 was removed by you from the lower strata, species 1 could occupy both the upper and lower strata. From the choices given below, what would be your inference from these observations?

In a natural system, a species producing large numbers of offsprings, with little or no parental care, generally exhibits which one of the following kind of survivorship curves?

Match the correct local names of temperate grasslands with their geographical range.
 Geographical         Local name of 
   range                   the grassland
1. Asia                   (a) Pampas
2. North America     (b) Prairies
3. South America    (c) Steppes
4. South Africa         (d) Veldt 

Following is a the hypothetical life table for a species.

Which one of the following is the correct net reproductive rate (R0)?

Which one of the following statements is true for the trends ofDissolved Oxygen (DO) and Biological Oxygen Demand (BOD) in a water stream receiving pollutants from point source?

Following are the graphical representations of various hypotheses proposed for explaining the possible relationships between species richness (X-axis) and community services (Y-axis).

Which of the following options is the correct match between the
graphical representations and the hypotheses?

Following are the plots representing biological rhythms at different time points depicted as; SR = Sunrise; N = Noon; SS = Sunset; MN = Midnight

Which of the plot(s) represent the ultradian biological rhythm(s)?

A Population of non-poisonous butterflies have the same colour pattern as some highly poisonous butterflies. Assume that the population of non-poisonous butterflies is higher than the population of poisonous butterflies. Given this, what will be the impact of this mimicry on the fitness of the population of the poisonous butterflies in the presence of the predator?

Given below is a graphical representation of changes imorphological features over a period of geological time scale, where population A accumulates heritable morphological changes and give rise to distinct species B. Population B splits into a distinct species B2.

Which of the above lineages represents the pattern of speciation by cladogenesis?

Red hair is a recessive trait in humans. In a randomly mating population in Hardy-Weinberg equilibrium, approximately 9% of individuals are red-haired. What is the frequency of the heterozygotes?

The frequency of M-N blood types in a population of 6129 individuals is as follows
Blood type    Genotype    Number of individuals
M    lmlm        1787
MN    lmlN      3039
 N    lNlN        1303
The frequency of LN allele in this population is

Mayfair genes (hypothetical) consist of a super family oftranscription factors. They are found in 4 clusters in mammals; in 2 clusters in insects; and in a single cluster in an ancestor to insects. These data consistent with all of the following explanations EXCEPT :.

Fluorescence recovery after photobleaching (FRAP) is a method to estimate the diffusion of molecules in a membrane. Fluorescently labelled molecules such as
1. a receptor tagged with Green Fluorescent Protein (GFP).
2. a receptor labelled with GFP which interacts with cytoskeleton.
3. a labelled lipid.
4. a labelled protein that binds to the membrane surface are photobleached and the recovery profiles (a-d) were obtained to estimate their diffusion coefficients.The following data were obtained :

Which one of the combinations is correct?

Agrobacterium Ti plasmid vectors are used to generate transgenic plants. The following are examples of vir gene-encoded proteins that are important for the transfer of T-DNA into plants:
1. Vir E, a single-stranded DNA binding protein.
2. Vir D2 that generates T-strands.
3. Vir A that senses plant phenolic compounds.
 4. Vir F which directs T-complex proteins for destruction in proteasomes.
Which one of the following combinations of proteins functions inside the plant cells?

A researcher is investigating structural changes in a protein by
following tryptophan fluorescence and by circular dichroism (CD). Fluorescence and CD spectra of a pure protein were obtained in the absence of any treatment (a), in the presence of 0.5 molar urea (b), upon adding acrylarhide, a quencher of tryptophan (c) and upon heating (d). The data are shown below :

Which one of the following statements is correct?

Polynucleotide kinase (PNK) is frequently used for radio-labelling DNA or RNA by phosphorylating 5'-end of non-phos-phorylated polynucleotide chains. Which of the following statements about PNK is NOT true? A. PNK catalyzes the transfer of a-phosphate from ATP to 5'-end of
polynucleotide chains (DNA or RNA).

A gene encoding for protein X was cloned in an expression vector under the T7 RNA polymerase promoter and lac operator. Cells were induced by the addition of 1 mM IPTG at 37°C for 6 h. Cells were lysed and fractionated into insoluble bodies and cell-free superantant by
centrifugation. Protein X is present in the in soluble bodies.Which one of the following strategies would you use to express protein X in the soluble fraction (cell free supernatant)?