Free CSIR NET JRF Life Science Online Mock Test 3

If gypsy moth egg density is 160 at time t and 200 at t + 1, what will be its value at time t + 3, assuming that egg density continues to increase at a constant rate?

To achieve the best resolution using a fluorescence microscope, what combination of the wavelength of emitted light (λ), refractive index and the angle (2 ) by which light enters into the microscope would be the best choice for the user:

Molecular polymorphic markers are already known with respect to tobacco mosaic virus (TMV) resistance in tobacco. Among these, which marker system you will select that will be simple, economic and less time consuming:

In an effort to produce gene knockout mice, gene-targeted homologous recombination was tried, with the exogenous. DNA containing neor gene (confer G-4l8 resistance) and tkHsv gene (confers sensitivity to the cytotoxic nucleotide analog ganciclovir). If the neor gene was inserted within the target gene in the exogenous DNA and considering that both homologous and non-homologous recombination (random integration) is taking place, which one of the following statements is NOT correct about the possible outcome of the experiment?

Poplar is a dioecious plant. A wild plant with genes AABBCC was crossed with a triple recessive mutant aabbcc. The F1 male hybrid (AaBbCc) was then back crossed with the triple mutant and the phenotypes recorded are as follows:

AaBbCc       300
aaBbCc        100
aaBbcc         16
AabbCc       14
AaBbcc       65
aabbCc      75
aabbcc      310
Aabbcc     120

The distance in map unit (mu) between A to B and B to C is …

If you remove a set of cells from an early embryo, you observe that the adult organism lacks the structure that would have been produced from those cells. Therefore, the organism seems to have undergone:

For two species A and B in competition, the carrying capacities and competition coefficients are
KA = 150 KB = 200
α= 1 β = 1.3

According to the Lotka-Volterra model of interspecific competition, the outcome of competition will be:

Two interacting genes (independently assorting) were involved in the same pathway. The absence of the function of either gene leads to the absence of the end product of the pathway. A dihybrid cross involving the two genes is carried out. What fraction of the F 2 progeny will show the presence of the end product?

The sequence of the peptide KGLITRTGLIKR can be unequivocally determined by:

Consider an autosomal locus with two alleles A1 and A2 at frequencies of 0.6 and 0.4 respectively. In each generation, A1 mutates to A2 at a rate of μ = 1 x 10-5 while A2 mutates to A1 at a rate of υ = 2 x 10-5. Assume that the population is infinitely large and no other evolutionary force is acting. . The equilibrium frequency of allele A1 is …

A person showed the symptoms of diarrhea, gas and pain whenever milk was consumed. The doctor advised the person to take curd instead of milk and subsequently the symptoms mostly disappeared due to this change of dairy product. The following statements are proposed to explain this observation:
A. The person has a deficiency in the intestinal sucrase-maltase
B. Curd is not deficient in sucrose and maltose
C. The person has a deficiency in the intestinal lactase
D. The bacteria in curd contain lactase

Which one of the following is true?

In a typical gene cloning experiment, by mistake a researcher introduced the DNA of interest within ampicillin resistant gene instead of lac Z gene. The competent cells were allowed to take up the plasmid and then plated in the media containing ampicillin, X-gal and IPTG and subjected to bluewhite screening. Considering all plasmids were recombinant which one of the following statements correctly describes the outcome of the experiment?

Constitutive photomorphogenesis (COP 1) protein, an E3
ubiquitin ligase, regulates the turnover of proteins required for
photomorphogenic development. Following are certain
independent statements related to the function of COP 1
protein:
A. In light, COP1 along with SPA1 adds ubiquitin tags to a subset of nuclear proteins.
B. The proteins ubiquinated by COP1 and SPA1 are targeted for degradation by the 26S proteasome.
C. In dark COPI is slowly exported to the cytosol from nucleus.
D. The absence of COP 1 in the nucleus permits the accumulation of transcriptional activators necessary for photomorphogenic development.

Which one of the following combinations is correct?

Fruit colour of wild Solanum nigrum is controlled by two alleles of a gene (A and a). The frequency of A, p=0.8 and a, q=0.2. In a neighbouring field a tetraploid genotype of S. nigrum was found. After critical examination five distinct genotypes found; which are AAAA, AAAa, AAaa, Aaaa and aaaa.

Following Hardy Weinberg principle and assuming the same allelic frequency as that of diploid population the numbers of phenotypes calculated within a population of 1000 plants are close to one of the following:

AAAA : AAAa : AAaa : Aaaa ; aaaa

From statements on protein structure and interactions detailed below, indicate the correct statement:

A researcher wants to obtain complete chemical information, i.e., head groups and fatty acids of phospholipids from liver tissues. Phospholipids have fatty acids of different lengths and unsaturation and also the head groups are of different chemistries. Which of the following combination of techniques would provide a complete chemical description of phospholipids?

The standard free energy change (∆Go) per mole for reaction A → B at 30°C in an open system is – 1000 cal/mole.
What is the approximate free energy change (∆G) when the concentrations of A and B are 100 micromolar and 100 millimolar, respectively?

Cancer is often believed to arise from stem cells rather than fully differentiated cells. Following are certain views related to the above statement. Which one of the following is NOT correct?

A male mouse cell line has a large translocation from X chromosome into chromosome 1. When a GFP containing transgene is inserted in this chromosome I with translocation, it is often silenced. However when inserted in the other homologue of chromosome 1 that does not contain the translocation, it is almost always expressed. Which of the following phenomenon best describes this effect?

Diagnosis of influenza virus infections can be done using some of the following techniques:

A. Western blot and Southern blot
B. Northern blot and western blot
C. ELISA and RT-PCR
D. PCR and electron microscopy
Choose the combination of techniques that correctly lists the detection methods:

The approximate P:B (Net Primary Production: Biomass) ratios in four different ecosystems (A, B, C, D) are A – 0.29; B – 0.042, C – 16.48; D – 8.2. The four ecosystems are

What would happen as a result of a transplantation experiment in a chick embryo where the leg mesenchyme is placed directly beneath the wing apical ectodermal ridge (AER)?

During the course of evolution, the jawbones got modified into three ear ossicles in mammals. Which one of the following is a correct match of all three ear ossicles and their jawbones?

One hundred independent populations of Drosophila are established with 10 individuals in each population, of which, one individual is of Aa genotype and the other nine are of AA genotype. If random genetic drift is the only mechanism acting on these populations, then, after a large number of generations, the expected number of populations fixed for the “a” allele is …

Orchids of the genus Cryptostylis are known to maintain reproductive isolation because their flowers look and smell like females of the wasps of genus Lissopimpla. When the male wasp visits and attempts to mate with the flower, the shape of anther and stigma allows correct placement and transfer of pollen to the wasp, which then transfers the pollen to a species-specific flower that it next attempts to mate with. This prezygotic barrier that prevents inter-species cross-pollination in Cryptostylis is best explained by:

Euphorbiaceae generally represents milky sap bearing plants but there are also some non-milky sap bearing plants that belong to this family. Identify the correct combination of the following given plants which belong to family Euphorbiaceae.

Some of the following transgenic approaches could be used for functional characterization of endogenous genes in plants:
A. Transformation using a binary vector containing a strong
enhancer element and lacking the right border of T-DNA
B. Transformation using a binary vector containing a promoter-less
reporter gene sequence and a selection maker gene cassette within
the T-DNA.
C. Transformation using a binary vector containing only a strong
enhancer element and a selection marker gene cassette within the
T-DNA.
D. Transformation using a binary vector lacking a reporter gene as
well as both the left and right borders of T-DNA.
Which one of the following combinations can be used?

It is hypothesized that the mean (μ0) dry weight of a female in a Drosophila population is 4.5 mg. In a sample of 16 females with ̅ = 4.8 mg and s = 0.8 mg, what dry weight values would lead to rejection of the null hypothesis at p = 0.05 level? (take t0.05=2.1)

From the following statements:
(A) Coloured images can be obtained by transmission electron microscopy by fluorescent labelling of the specimen
(B) Scanning electron microscopy requires sectioning of the sample
(C) Confocal microscopy uses optical methods to obtain images from a specific focal plane and excludes light from other planes
(D) Differential-interference microscopy relies on interference between polarized light due to differences in the refractive index of
the object and surrounding medium
(E) Visualization in epifluorescence microscopy requires staining by heavy metal atoms
Choose the combination with two correct and one incorrect statement:

The following statements are made to describe auxin signal transduction pathway, from receptor binding to the physiological response:
A. Auxin response factors (ARFs) are nuclear proteins that bind to auxin response elements (Aux REs) to activate or repress gene transcription.
B. AUX/IAA proteins are secondary regulators of auxin-induced gene expression. Binding of AUX/lAA proteins to the ARF protein blocks its transcription regulation. .
C. Auxin binding to TIRI/AFB promotes ubiquitin-mediated degradation and removal of AUX/lAA proteins.
D. Auxin binding to auxin response factors (ARFs) causes their destruction by the 26S proteasome pathway.

Which one of the following combinations of above statements is correct?

Given below are statements on key characteristics of two fungal lineages.

(A) Microsporidia do not have true mitochondria
(B) Most chytrids produce flagellated gametes
(C) Microsporidia are usually free-living
(D) Chytrids reproduce sexually without a dikaryon stage
Choose the combination with statements

Given are certain facts which define ‘determination’ of a developing embryo.
A. Cells have made a commitment to a differentiation program.
B. A phase where specific biochemical actions occur in\ embryonic cells.
C. The cell cannot respond to differentiation signals.
D. A phase where inductive signals trigger cell differentiation.
Which of the above statements best define determination?

A majority of humans with normal colour vision was found to be more sensitive to red light in the Rayleigh match, where the subject mixed a variable amount of red and green light to match monochromatic orange. Which one of the following statements is NOT true to explain the observation?

If a metabolically active cell is challenged with the 55Fe radioisotope label, which of the following proteins CANNOT be detected by autoradiography?

Given below are larval stages and phylum to which they belong. Select the INCORRECT combination.