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Previous Year Questions

TLS Online TPP Program

QUESTION ID:1

In a lac operon, a nonsense mutation in the gene encoding beta-galactosidase was found to interfere with the expression of downstream permease and transacetylase genes. Which one of the following may explain this observation most appropriately?

QUESTION ID:2

Which one of the following curves correctly depicts the relationship of the NPP/GPP ratio with latitude?

QUESTION ID:3

Which one of the following options best represents the sequence of events leading to the phenomenon of introgression?

QUESTION ID:4

Which one of the following conditions associated with chromosome 15 may cause Prader-Willi syndrome?

QUESTION ID:5

In a cooperatively breeding species, under which condition is a helper more likely to exhibit philopatry?

QUESTION ID:6

Which one of the following is NOT a characteristic feature of platelets present in human blood :

QUESTION ID:7

To examine the in vivo co-localization pattern of two different proteins using fluorescently labeled antibodies, which one of the following combinations of fluorochromes will be appropriate?

QUESTION ID:8

Which one of the following statements is correct?

QUESTION ID:9

The two phylogenetic trees given below represent evolutionary patterns in species or population. The differently colored or dashed lines represent a single species or gene genealogy.
Select the option that correctly identifies the type of evolutionary process that these two figures represent.

QUESTION ID:10

Parathyroid hormone (PTH) regulates calcium homeos tasis in humans. The following statements are made regarding PTH:
A. It is a 108 amino acid (aa) residue long honnone whose 1-42 aa exhibits full biological activity.
B. It is an 84 aa hormone whose 1-34 aa exhibits full biological activity.
C. An acute decrease of Ca++ results in a marked increase of PTH mRNA, followed by increased rate of PTH synthesis.
D. Rate of degradation of pro-PTH increases when Ca ++concentrations are low.
E. Cathepsin B cleaves PTH into two fragments.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:11

Shown below is the proton coupled carbon-13 NMR spectrum of sodium trimethylsilylpropanesulfonate (DSS), a common internal chemical shift standard used in NMR spectroscopic studies of proteins and peptides. Also shown on the spectrum is the structure of DSS in which the different carbon atoms have been labeled a-f. The peaks in the NMR have been
labeled 1-4. 
Which of the following represents the correct assignments for the carbons in DSS? (Hint - The nuclear spin quantum numbers of 1H and 13C are I = 1/2)

QUESTION ID:12

Given below are the list of plant derived alkaloids and their uses in modern medicine.

Which one of the following options represents all correct matches?

QUESTION ID:13

Given below are the list of some of the most rare species on our planet (Column X) and the regions of the world where they occur (Column Y).

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

QUESTION ID:14

When budding yeast (a facultative anaerobe) is grown for a few days in medium containing high glucose it shows a growth pattern with two lag phases (see figure below).
Which one of the following statements best explains this growth pattern?

QUESTION ID:15

The following statements are made regarding cytokinin (CK) biosynthesis in plants:
A. Trans-zeatin (tZ) and iso-peptenyladenile (iP) are common active forms of isoprenoid CKs.
B. CKs are present as nucleoside and glycosidic conjugates but not as nucleotide conjugates.
C. Dephosphorylation and deribosylation steps are involved in two-step pathway for active CK formation.
D. Lonely Guy (LOG) enzyme is involved in CK metabolism
Which one of the following options represents the combination of all correct statements?

QUESTION ID:16

Two mutations were isolated in bacteriophage, one causing clear plaque (c) and the other causing minute plaque (m). The genes responsible for these two mutations are 9 cM apart. The plaques with genotype c+ m- and c-m+ were mixed to infect bacterial cells. The progeny plaques were collected, cultured and plated on bacteria.
The expected number of the different types of plaques are shown below:
A. c+ m+ 455, c+ m- 45, c- m+ 45, c- m- 455
B. c+ m+ 455, c+ m- 455, c-m+ 45, c- m- 45
C. c+ m+ 45, c+ m- 455, c- m+ 455, c- m- 45
D. c+ m+ 65, c+ m- 680, c- m+ 685, c- m- 70
Which one of the following options represents the combination of all correct statements?

QUESTION ID:17

A researcher isolated a mutant of an ER resident protein-folding enzyme (PFE) that has lost its KDEL sequence (ER retention sequence). Potential consequences of such a mutation are given below.
A. PFE is found in the extracellular space
B. PFE is degraded in the ER
C. Unfolded proteins increase in the ER
D. PFE is transported to the cytosol
Which one of the following options represents the combination of all correct statements?

QUESTION ID:18

Column X lists various plant types and Column Y lists key features of these plants.

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

QUESTION ID:19

Given below are the approximate lengths of DNA fragments obtained on agarose gel electrophoresis following restriction digestion of a 3kb circular plasmid with different restriction
enzymes:
BamHI : 0.5kb, 2.5kb
HincII : 3 kb
EcoRI : 3 kb
EcoRI + BamHI : 0.5kb, Ikb, 1.5kb
EcoRI + HincII : 1.3kb, 1.7kb
BamHI + HincII : 0.2kb, 0.3kb, 2.5kb
Based on the above information, which one of the following statements is INCORRECT?

QUESTION ID:20

The enzyme-catalysed reaction shown below follows Michaelis-.Menten kinetics.

From the information given above, calculate Km and Ks.

QUESTION ID:21

Following statements are made about the chemical properties and distributions of the respiratory pigments found in animals:
A. Hemoglobins are the most common and widespread respiratory pigments in vertebrates and invertebrates and are always present in blood cells.
B. The heme structure in hemoglobins is an iron (ferrous) porphyrin which varies widely among species, and also varies among the different molecular forms of hemoglobin within any single species. The globin, however is exactly identical.
C. Hemocyanin contains copper and tums bright blue when oxygenated and it is always dissolved in the plasma.
D. Chlorocruorins are similar to hemocyanin, but have a lower affinity for oxygen binding than hemocyanin present in blood cells of some marine annelid worms.
E. Hemerythrins are non-heme, iron-containing respiratory pigment that have a limited and scattered distribution.
Which one of the following options represents the combination of all INCORRECT statements?

QUESTION ID:22

The following experiment was designed to establish the synergy of Bc12 with genes like Myc in leading to B-cell lymphomas.

Identify the figure that correctly represents conditions under which mice succumbed to lymphomas.

QUESTION ID:23

You are sampling birds in a forest community to determine species diversity of birds in this region. How would you assess the sampling effort to ensure that you have obtained a reasonable estimate of the diversity in the region?

QUESTION ID:24

Given below are a few statements on mapping populations and marker-assisted selection (MAS):
A. MAS can be used to eliminate undesirable genotypes early in the breeding program by screening plants at the seedling stage.
B. In backcross breeding programs, breeders use molecular markers to select against the donor genome to accelerate recovery of the recurrent parent genome.
C. Among different types of mapping populations, F2 and F2:3 populations are immortal populations.
D. Near Isogenic Lines (NILs) can be produced by repeated self-pollination of F1. 
Which one of the following options represents the combination of all correct statements?

QUESTION ID:25

Cytoskeleton-dependent motor proteins are critical for the movement of cellular organelles in animal cells. In the fertilized egg of C. elegans, once the polarity has been established, the maternal nucleus migrates towards the paternal nucleus, which eventually leads to fusion of the two pronuclei (see below).
What molecular motor is likely to be directly involved in nuclear migration?

QUESTION ID:26

The figure below represents the data from immunoblots (IB) of co-immunoprecipitation (IP) experiments with antibodies as indicated, after HeLa cells were treated with arsenic (β-cat refers to β-catenin; and E-cad refers to E-cadherin).
The following assumptions were made:
A. Arsenic activates the non-canonical β-catenin pathway.
B. Arsenic leads to cellular prolife.ration.
C. Arsenic leads to proteasomal degradation of β-catenin.
D. Arsenic induces apoptosis in the HeLa cells.
Which one of the following options represents the combination of all correct assumptions?

QUESTION ID:27

The following are some statements made regarding mutations:
A. Change of DNA sequence fromAGC to ATC in non-coding strand can have a major impact on the protein production.
B. Suppressor mutation restores the original phenotype, only when a second mutation occurs at the original site of the m11tation.
C. Mutation rates remain the same in all organisms.
D. Strand slippage during replication is a consequence of loop formation in one strand of DNA
E. Hydroxylamine adds a hydroxyl group only on cytosine.
Which one of the following options represents the combination of all INCORRECT statements?

QUESTION ID:28

Behavioral and cognitive responses in organisms are finely tuned to environmental cues. Given below is a list of specific hormone/chemical signals (Column X) and biological functions (Column Y).
Select the option that represents all correct matches between Column X and Column Y.

QUESTION ID:29

An investigator identified a nuclear localization signal (NLS; Pro-Lys-Lys-Lys-Arg-Lys) at the C-terminus of the protein X (50 kDa). To analyse the localization of protein X, the investigator fused protein X with GFP at the C-terminus. The fusion protein was detected in the cytosol. When the nuclear localization signal was fused with GFP at the N-terminus, the NLS-tagged GFP extensively localized in the nucleus. Based on this observation, the investigator made a few hypotheses:
A. The basic amino-acid stretch in the protein X-GFP chimeric construct is masked by the GFP sequence and thus not capable of directing entry of protein X-GFP into the nucleus.
B. The X-protein in the full-length X-GFP chimeric protein is post-translationally modified that impacts its import into the nucleus.
C. Fusion with GFP makes the protein X too bulky to enter the nucleus through the nuclear pore complex.
D. The GFP is post-translationally modified that impacts the import of protein X-GFP into the nucleus.
Which one of the following options gives the combination of all possible hypotheses that best explain Protein-X's trafficking mechanisms?

QUESTION ID:30

In wild type C. elegans hermaphrodites, two adjacent cells, Z1.ppp and Z4.aaa, have the potential to become the anchor cell. They interact in a manner that causes one of them to become the anchor cell, while the other one becomes the precursor of the uterine tissue. The following statements are given to describe the interaction of the two cells:
A. The cell secreting LAG-2 becomes the anchor cell.
B. The cell secreting LIN-12 remains as the precursor of the uterine tissue.
C. The LIN-12 secreting cell takes the fate of anchor cell while the LAG-2 secreting cell takes the fate of uterine precursor cell.
D. The Hippo kinase signaling pathway brings lateral inhibition so that one cell is inhibited and the other cell is promoted to become the anchor cell.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:31

Columns X and Y of the following table list some treatment methods, reagents, and events that are related to human lymphocyte culture, and banding/ karyotyping of human chromosomes.

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

QUESTION ID:32

The plot below has two curves (A, B) that show the fractional occupancy of hemoglobin and myoglobin by oxygen as a function of the amount of oxygen.

YO2 is the fraction of oxygen-binding sites occupied by oxygen. pO2 is partial pressure of oxygen. From the options given below, select the option with the right curve (A, B), reaction (i, ii) and equation/s (I, II, III, IV) that describe oxygen binding to hemoglobin and myoglobin.

QUESTION ID:33

Following figure shows the early interactions between the Apical Ectodermal Ridge (AER) and the limb bud mesenchyme. The red lines with block head indicate repression while the black lines indicate activation.
The following statements were made regarding the development of a tetrapod limb:
A. When the limb bud grows Sh.h creates a new signalling centre that induces the posterioranterior polarity.
B. When the concentration ofFGFs rises, it can inhibit Gremlin thus allowing BMPs to begin repressing the AER-FGFs.
C. FGFs 4, 9 and 17 from the AER inhibit Shh to stabilize the ZPA.
D. Repression of Gremlin synthesis helps maintain the AER.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:34

The following statements were made about Laser Scanning Confocal Microscopy (LSCM).
A. LSCM is a wide field technique with Kohler illumination system.
B. Spatial resolution higher than that achieved in wide field imaging could be obtained if only the central portion of an Aity Disk is used to form an image.
C. Scanning mirrors sweep the excitation beam over the sample point-by-point to build the image.
D. An altered pinhole size does not make any impact on the resolution of the image.
E. A photomultiplier tube (PMT) in LSCM helps in generating real colour of fluorophores.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:35

The number of individuals of different species in two communities P and Q is given below.

Based on the given data, select the correct statement?

QUESTION ID:36

Pyruvate generated by glycolysis, is converted to acetyl-coenzyme A, which is metabolized by the citric acid cycle generating energy-rich molecules. From the choices given below, select the right combination of these molecules produced from one molecule of acetyl-CoA.

QUESTION ID:37

Column X lists evolutionary ideas and scientists who proposed them, and Column Y lists the description of these ideas.

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

QUESTION ID:38

The following statements are made regarding male reproductive system, particularly with reference to spermatogenesis and sperm production:
A. The membranes of spermatozoa contain germinal angiotensin-converting enzyme (gACE).
B. Mature spermatozoa are released from Leydig cells.
C. Sertoli cells secrete Mullerian inhibiting substance (MIS).
D. Sertoli cells synthesize androgens.
E. Rete testis has high content of estrogen and alpha estrogen receptors (ERa).
Which one of the following options represents the combination of all correct statements?

QUESTION ID:39

A mutant DNA polymerase was found to have higher error rate and synthesized only short DNA fragments. In the statements below, potential explanations are given.
A. The 5' to 3' exonuclease activity is compromised.
B. The 3' to 5' exonuclease activity is compromised.
C. The polymerase tends to frequently dissociate from the template.
D. The polymerase is unable to unwind the DNA template during replication.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:40

The following statements refer to the observations made by a student, upon using 2,6-dichloroisonicotinic acid (INA) to induce systemic acquired resistance (SAR) in tobacco. INA treatment,
A. enhances salicylic acid concentration in plants.
B. does not enhance salicylic acid concentration in plants.
C. fails to activate SAR in nahG-expressing plants.
D. activates SAR in nahG-expressing plants.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:41

Column X lists proteins that play a role in mediating DNA recombination processes and Column Y lists the possible functions of these proteins.

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

QUESTION ID:42

The two columns given below lists various organisms and their dispersal and distribution status in India.

Which one of the following options represents all correct matches between the above two columns?

QUESTION ID:43

How long should it take the polypeptide backbone of a 6-residue, 10-residue, 15-residue and 20-residue folding nucleus to explore all its possible conformations? Assume that the polypeptide backbone randomly reorients every 10-13 seconds (s).

QUESTION ID:44

In Drosophila, a cross was set between a male homozygous for alleles s +Is+ (phenotype A) and a female homozygous of sis (phenotype B) ('s+' being a dominant allele and 's' a recessive allele). All of the Fl individuals thus obtained had the phenotype B. When F 1 individuals were crossed among themselves, all progeny obtained were of phenotype A in F2.
The following explanations were proposed for the results obtained:
A. This is an example of cytoplasmic inheritance.
B. This is exhibiting genetic maternal etlect.
C. This is a quantitative trait influenced by the environment.
D. This is exhibiting gene interaction with epistasis.
E. The trait is showing position effect variegation.
Which one of the following option is correct?

QUESTION ID:45

Which of the following plots best depicts growth as per the logistic equation?

QUESTION ID:46

Two protein kinases, K1 and K2, regulate an intracellular pathway in response to the extracellular signal. The following observations were made regarding the pathway.
i. Response is observed even in the absence of an extracellular signal when a mutation permanently activates K1.
ii. Response is observed even in the absence of an extracellular signal when Kl contains an activating mutation and K2 has an inactivating mutation.
iii. No response is observed even in the presence of an extracellular signal when K2 is inactivated by mutations.
iv. Response is observed even in the absence of an extracellular signal when both kinases are activated by mutations.
Which one of the following statements is correct?

QUESTION ID:47

To obtain recombinant products during meiosis, a double-strand break in the DNA yields crossovers needed for chiasmata formation. The progression of the non-crossover and crossover pathways begins with the formation of D loop, however, it may not result in the production of recombinant gametes.
Following statements are made regarding recombination:
A. Expansion of D-loop takes place in non-crossover pathway, but not in the crossover pathway.
B. Expansion of D-loop takes place in crossover pathway, but not in the non-crossover pathway.
C. Ejection of elongating strand takes place in the non-crossover pathway, but not in the crossover pathway.
D. Ejection of elongating strand takes place in the crossover pathway, but not in the non-crossover pathway.
Which one of the following options represents the correct combination of statements that explain the formation of recombinant gametes?

QUESTION ID:48

The following statements are made with regard to the optical activity of amino acids derived from natural proteins:
A. All alpha-amino acids have the D stereochemical configuration.
B. All L-amino acids have the (S) absolute configuration except cysteine, which has the (R) absolute configuration.
C. All D-amino acids have the (S) absolute configuration except cysteine, which has the (R) stereochemical configuration.
D. In the absolute configuration system, L-threonine and L-isoleucine are (2S, 3R)-threonine and (2S, 3S) -isoleucine diastereomers, respectively.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:49

The following statements are made about post-transcriptional processing:
A. RNA editing can occur via the deamination of cytosine residues, .leading to formation of uracil and thus a change in coding sequence.
B. The major spliceosomal complex mediates the removal of Group II introns.
C. Trans-splicing events seen in trypanosomes allow the formation of multiple gene products by bringing together ditTerent combinations of exons of three or more genes.
D. Capping of eukaryotic mRNAs occurs exclusively in the nucleus of the cell.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:50

Bacteriophage A proteins, CI and Cro are crucial reguliaiors of the lysogeny and lytic cycles of the bacteriophage. These proteins bind to the rightward operator region consisting of OR1, OR2, and OR3 (shown below).
Which one of the following statements about the regulation by CI and Cro proteins is CORRECT?

QUESTION ID:51

Given below is the list of viruses in Column X and their receptors in human host cells in Column Y.

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

QUESTION ID:52

Given below are some statements that are associated with transgenic plants. Each statement has a blank space indicated by '_______'.
A. A transgenic plant with two functional copies of a transgene can segregate in a _____ ratio for the transgenic phenotype on self-pollination if the two genes are linked.
B. The ____ system can be used for removal of marker genes from transgenic plants.
C. The endogenous plant gene, ________ , can be used to engineer resistance to imidazolinone herbicides.
D . Variations in transgene expression levels between five independent transgenic lines generated  using the same T-DNA construct can be due to _______ .
Which one of the following options has the correct sequence of terms that can be used to fill in the blanks in the above statements (from A to D) such that all statements become true?

QUESTION ID:53

The figure below represents the fundamental and realised niche of two species.

Which one of the following options correctly identifies the fundamental niche and realised niche of any one of the species?

QUESTION ID:54

The following statements are potential explanations for the continued existence of genes that control eye development in eyeless cavefish.
A. They have inherited these genes from their ancestors and this remains even though they no longer have eyes.
B. In case of a possibility tl1at they return to tlle smface environment retention of vision would be advantageous, so evolution retains this trait.
C. Evolution can only lead to gain of a trait, not loss of a trait.
D. These genes are retained because of combined role of these genes with other sensory mechanisms.
Which one of the following options represents the combination of correct statements?

QUESTION ID:55

Males of a species of grasshopper produce loud calls to attract females. Most energy of these calls lie in the species-specific frequency, while other frequencies have much less energy. This is depicted in a power spectrum (plots with solid line in the figures below). Females find males by listening to and recognizing the species-specific call, and they are most sensitive to the species specific frequency. This is depicted using hearing threshold curves (plots in dashed lines in the figures below). This allows females to find even the softest calling males of their own species and ignore even the loud callers of other species, resulting in reproductive isolation.
Which one of the following figures represents the correct option for the hearing threshold (dashed lines) of females, given the power spectrum (solid lines) of male calls of this grasshopper species?

QUESTION ID:56

The following statements are made regarding materials transported through the phloem of a plant.
A. Only reducing sugars are translocated.
B. Non-reducing sugars are generally translocated.
C. Sucrose and raffinose are generally translocated.
D. Only D-glucose and D-fructose are translocated.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:57

The following is the life table of a natural population of a small annual succulent where 'x' is its life phase, 'lx' is its survivorship till that stage and 'dx' is its age specific mortality.
Which of the following options from the above life phases show the lowest age specific mortality rate?

QUESTION ID:58

Two batches of antibodies (Q and R) were generated for an antigen and affinities of both the antibodies were assayed using pure antigen. Given below are Scatchard plots obtained for the antibody-antigen binding assays and the inferences drawn upon Scatchard analysis.
A. Antibody Q is possibly a monoclonal while R is polyclonal
B. The curved nature of Scatchard plot for R indicates that it cross-reacts with the blocking reagent
C. The average affinity of R is more than affinity of Q to the antigen
D. Antibody Q is possibly IgA and R is IgG
E. The valency of the antibodies cannot be inferred from the Scatchard plots.
Select the option that groups all the correct inferences .

QUESTION ID:59

The figure below depicts the evolutionary tree of organisms based on characteristics that are depicted as numbers (i-iv).

Choose the option that correctly matches the characteristics to the numbers:

QUESTION ID:60

The theory of island biogeography has synthesized into theory the following concepts, except :

QUESTION ID:61

Following statements are made about fertilization occuring in sea urchins:
A. Chemoattraction of the sperm to the egg is mediated by sperm activating peptides like bindin.
B. Exocytosis of the sperm acrosomal vesicles and release of enzymes occur.
C. The capacitated sperm undergoes acrosome reaction.
D. The acrosome protein mediating the critical species-specific binding event is resact.
E. The slow block to polyspermy is accomplished by the cortical granule reaction.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:62

The diagram below depicts the relationship of land plants with some of the major apomorphies indicated.

Below is a list of apomorphies that have not been labeled on the tree above.

i. Intercalary growth of sporophyte

ii. Oil bodies

iii. Archegonium

iv. Leptoids

Which one of the following options correctly matches the apomorphies with their positions on the tree?

QUESTION ID:63

Following statements with respect to development in sea urchin were put forth:
A. The cell fates are determined both by autonomous and conditional modes of specification.
B. Large micromeres are conditionally specified.
C. Large micromeres produce paracrine and juxtacrine factors that specify the fates of their neighbours.
D. β-catenin is not required for the specification of the micromeres.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:64

Shown below are the CD spectra of a protein recorded under two different conditions.

From the options given below, select the one that is the best interpretation of the spectra.

QUESTION ID:65

Given below are some statements with blank spaces indicated by ' ___'.
A. A plasmid cloning vector digested with an enzyme (with a single restriction site in the plasmid) that generates 3' overhangs can be made blunt-ended using ______
B. DNA with a nucleotide composition of 30% A, 35% G, 20% C and 15% Tis most likely _________ .
C. Production of only truncated molecules of trans gene-derived mRNA in transgenic plants generated using a transgene from a prokaryotic source is most likely due to ____
D. ______ is a method for identifying the positions where  individual DNA-binding proteins attach to a genome.
Which one of the following options has the correct sequence of terms that can be used to complete the above statements (from A to D) such that all statements become true?

QUESTION ID:66

In an experiment, immunophenotyping of human blood cells was done to analyse the relative number of CD8+ T cells and CD4+ T cells. The following antibody-fluorochrome conjugates for staining different blood cells were available:
i. CD19-FITC forB lymphocytes
ii. CD8-CY7 PE for T lymphocytes
iii. CD4-Cy7 PE for T lymphocytes
iv. CD3-PE for T lymphocytes
v. DAPI for nucleus
Which one of the following options gives the correct sequence of antibody-fluorochrome conjugates, to be used to sort the relative abundance of CD8+ and CD4+ cells in the given blood sample by FACS?

QUESTION ID:67

Many species of birds call at dawn in temperate regions. The phenomenon is referred to as "Dawn Chorus". Several explanations have been proposed for this. Which one of the options is NOT a correct explanation for the occurrence of "Dawn Chorus"?

QUESTION ID:68

The following statements are made regarding the characteristic features of body temperature in humans:
A. The core body temperature varies least with the changes of environmenta l temperature.
B. During severe muscular exercise the rectal temperature may rise up to 40°C.
C. The oral temperature is relatively higher than the rectal temperature.
D. The core body temperature is highest at 6:00AM and lowest in the evening in humans who sleep at night and remain awake during day time.
E. The temperature of scrotum is regulated at 3 7°C.
F. In women, a rise of basal body temperature occurs immediately after ovulation.
Which one of the following options represents the INCORRECT combination of the statements?

QUESTION ID:69

In a tissue, cells are bound together by physical attachment between cell to cell or between cell to the extracellular matrix. The following are some of the characteristics of cell junctions:
A. Tight junctions are cell-cell junctions connecting the intermediate filament in one cell with that in the adjacent cell.
B. Desmosomes are cell-matrix anchoring junctions connecting actin filament in one cell to the extracellular matrix.
C. Gap junctions are channel-formingjunctions allowing the passage of small water-soluble molecules ±rom cell to cell.
D. Tight junctions are occluding junctions that seal the gap between two cells.
E. Hemidesmosomes are cell-matrix anchoring junctions connecting intermediate filaments in one cell to the extracellular matrix.
Which one of the following options represents the combination of ALL INCORRECT statements?

QUESTION ID:70

During water stress, ABA increases dramatically in leaves causing stomatal closure. Given below are the various events involved in this process.
A. Opening of plasma membrane Ca2+ permeable ion channels and elevation of cytosolic Ca2+
B. Activation of plasma membrane anion channels, efflux of anions and potassium ions.
C. Binding of ABA to cytosolic ABA receptor and inhibition of activity of Type 2C protein phosphatases (PP2Cs).
D. Phosphoqlation and activation of NADPH oxidases (RBOH) and formation of apoplastic ROS.
Which one of the following options represents the correct sequence of events involved?

QUESTION ID:71

Given below are the five experiments (A-E) showing effects of duration of the light and dark periods on flowering of the short-day plants (SDP) and long-day plants (LDP).

Which one of the following options represents the combination of all correct flowering responses?

QUESTION ID:72

Following statements are made regarding amphibian development:
A. Fibronectin plays an important role in enabling the mesodermal cells to migrate into the embryo.
B. Organizer secrete proteins that block the BMP signal, which allows the ectodermal cells to become epidermis.
C. Wnt signalling causes a gradient of β-catenin along the anterior-posterior axis of the neural plate, which appears to specify the regionalization of the neural tube.
D. The more ventral blastomeres in the endoderm have high expression of nodal-related proteins.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:73

The following represents selected AFLP bands (I to V) observed in parents (P1 and P2), F1 progeny and 20 doubled haploid (DH) progeny developed from the F1. DH are created through chromosome doubling of pollen grains in anther culture.
The following statements were made about the above AFLP bands:
A. Bands I and IV are allelic.
B. Bands II and V assort independently.
C. Band III is uninformative.
Which one of the following options represents a combination of all correct statements?

QUESTION ID:74

Following statements are made about the bacterial ribosomes and their functions:
A. Association of23S rRNA with 16S rRNA is essential to catalyze in vitro peptide bond formation using model substrates.
B. The 23S rRNA is necessary and sutiicient to catalyze in vitro peptide bond formation using model substrates.
C. Ribosome carries a polymerization activity.
D. The 16S rRNA is necessary and sufficient to catalyze in vitro peptide bond formation using model substrates.
Which one of the following options represents the combination of both correct statements?

QUESTION ID:75

The following statements were made about X-chromosome inactivation in humans:
A. Maternally-derive d X-chromosome has a greater chance of becoming inactivated in any given cell.
B. Both X-chromosomes are activated dming the process of oogenesis.
C. The XIST gene encodes for a single, long non-coding transcript, which binds with the X-chromosome and helps in its inactivation.
D. The XIST gene expression is required to initiate inactivation of X- chromosome, and also to maintain inactivation from one cell generation to the next.
E. Tsix transcription affects the abundance of Xist RNA in cis.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:76

Select the rare or endangered species which also have exceptionally low genetic variability, as documented by multi-locus molecular methods.

QUESTION ID:77

The aminoacyl-tRNA synthetases (AARSs) in an organism have evolved to catalyze aminoacylation of their cognate tRNAs

QUESTION ID:78

A founder population has an Aa heterozygous genotype with a frequency of 1, and no individual with either AA or aa genotypes. With repeated self-fertilization, the frequency of AA. Aa and aa after three generations will be :

QUESTION ID:79

Below are some of the proposed roles of reactive oxygen species (ROS) in plant defense.
A. H2O2 may be directly toxic to pathogens
B. In presence of iron, H2O2 gives rise to an extremely reactive hydroxyl radical.
C. H2O2 leads to induced biosynthesis of salicylic acid (SA).
D. H2O2 production is always delayed during incompatible interactions.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:80

In yeast, under anaerobic conditions, pyruvate is fermented to ethanol through two steps : decarboxylation of pyruvate to acetaldehyde and NADH-mediated reduction of acetaldehyde to ethanol. The mammalian liver also expresses alcohol dehydrogenase (Liver ADH: L-ADH). From the options given below, choose the one that best explains the physiological significance of L-ADH in the absence of fermentation in the liver.

QUESTION ID:81

The effects of stimulation of cholinergic vagal fibers on the pacemaker potential of the cells of sinoatrial (SA) node of heart and on the nodal impulse generation are suggested below:
A. The nodal cell membrane becomes depolarized.
B. The slope of the pacemaker potential is increased.
C. The K+ conductance of nodal cell membrane is decreased.
D. The depolarizing effect of 'h' current (Ih) on the membrane potential is slowed down due to the opening of G protein gated K+ channels.
E. The opening of Ca ++ cha1mels are slowed down due to the decreased cAMP level in the nodal cells.
Which one of the following options represents the combination of all correct statements?

QUESTION ID:82

Blood hemostasis is the interplay of several intrinsic and extrinsic factors. Deficiency of some of the blood clotting factors and their clinical manifestations are listed below.
Which one of the following options represents all correct matches?

QUESTION ID:83

The figure below depicts the absorption spectra of chlorophylls and carotenoid over a range of wavelengths.
Which one of the following combinations best describes A, B and C from the absorption spectra shown above?