CSIR NET · Life Sciences
June
2019
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125 questions
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Q21
mcq
The site of the division plane during cytokinesis of animal cells is determined
a.
by position of nucleus
b.
by the central spindle
Correct Answer
c.
by the pre-prophase band
d.
randomly
Step-by-Step AI Explanation
Verified Method
In animal cells, the position of the division plane during cytokinesis is determined by the mitotic spindle apparatus, particularly signals from the astral microtubules and the central spindle (spindle midzone). The pre-prophase band determines the division plane in plant cells, not animal cells.
Q22
mcq
To prepare individual tissue cells from a primary culture, the cell-cell and cell-martix interaction must be broken. To achieve this, one would NOT use :
a.
EDTA
b.
Trypsin
c.
Collagenase
d.
Separase
Correct Answer
Step-by-Step AI Explanation
Verified Method
To dissociate cells from tissues or culture dishes, proteolytic enzymes like trypsin and collagenase, alongside chelating agents like EDTA (which disrupts $\text{Ca}^{2+}$-dependent cell-cell adhesion mediated by cadherins), are commonly used. Separase, on the other hand, is an intracellular endopeptidase that cleaves cohesin during the metaphase-to-anaphase transition of the cell cycle and is not used for tissue dissociation.
Q23
mcq
Which one of the following statements is NOT true about nucleosomal organization of core particle ?
a.
The typical structure of DNA is altered in the middle of the core particle
b.
In core particle, DNA is organized as flat super helix with 1.65 turns around the histone octamer
c.
While forming 30 nm fibers, generally 6 nucleosides per turn organize into a two-start helix
d.
The N-terminal histone tails in a core particle are strictly ordered and exit from the nucleosomes between turns of the DNA
Correct Answer
Step-by-Step AI Explanation
Verified Method
The N-terminal tails of core histones are intrinsically disordered and highly flexible; they are not strictly ordered in the crystal structure of the nucleosome core particle. Therefore, statement D is incorrect.
Q24
mcq
During replication, RNaseH removes all of the RNA primer except the ribonucleotide directly linked to the DNA end. This is because
a.
it can degrade RNA and DNA from their 5' end
b.
it can only cleave bonds between two ribonucleotides
Correct Answer
c.
it can degrade RNA and DNA from their 3' end
d.
activity of RNaseH is inhibited by the presence of duplex containing both strands as DNA
Step-by-Step AI Explanation
Verified Method
RNase H is a ribonuclease that specifically cleaves the phosphodiester bonds between two adjacent ribonucleotides within an RNA:DNA hybrid. It cannot cleave the phosphodiester bond between the final ribonucleotide and the first deoxyribonucleotide of the DNA chain, which must instead be removed by a 5' to 3' exonuclease (such as FEN1/DNA polymerase I).
Q25
mcq
Which one of the statements on protein conformation, detailed below is INCORRECT?
a.
L-amino acids can occur in Type $\text{I},\beta-\text{turns}$ where $\phi, \psi$ are both positive
b.
A peptide rich in proline is unlikely to adopt $\alpha-\text{helical}$ structure
c.
Proline residues have high propensity to occur in $\beta-\text{turns}$
d.
The dihedral angle $\phi,\psi$ of amino acids in unfolded proteins are exclusively positive
Correct Answer
Step-by-Step AI Explanation
Verified Method
In unfolded (denatured) proteins, the polypeptide chain samples a wide range of conformationally allowed regions in the Ramachandran plot, where most allowed combinations of $\phi$ and $\psi$ actually have negative $\phi$ values (such as the $\beta$-sheet and $\alpha$-helical regions). They are certainly not 'exclusively positive'.
Q26
mcq
Choose the INCORRECT statements from the following statements made for an enzyme-catalyzed reaction
a.
The kinetic properties of allosteric enzymes do not diverge from Michaelis-Menten behaviour
Correct Answer
b.
In feedback inhibition, the product of a pathway inhibits an enzyme of the pathway
c.
An antibody that binds tightly to the analog of the transition state intermediate of the reaction $\text{S} \rightarrow \text{P}$, would promote formation of P when the analog is added to the reaction
d.
An enzyme with $Kcat = 1.4 \times 10^4\text{ s}^{-1}$ and $Km = 9 \times 10^{-5}\text{ M}$ has activity close to the diffusion controlled limit
Step-by-Step AI Explanation
Verified Method
Statement A is incorrect because allosteric enzymes exhibit sigmoidal (cooperative) kinetics, which clearly diverge from classical hyperbolic Michaelis-Menten kinetics. (Note: Statement C could also be poorly phrased in the original exam, but A is directly false by definition).
Q27
mcq
On sequence analysis of a double stranded DNA, the results showed the content of cytosine, C was 20%. What is the amount of A and T put together ?
a.
20%
b.
30%
c.
50%
d.
60%
Correct Answer
Step-by-Step AI Explanation
Verified Method
According to Chargaff's rules for double-stranded DNA, the percentage of cytosine (C) equals guanine (G). If $\text{C} = 20\%$, then $\text{G} = 20\%$, meaning $\text{G} + \text{C} = 40\%$. Therefore, the remaining fraction is $\text{A} + \text{T} = 100\% - 40\% = 60\%$.
Q28
mcq
The first step in glycogen breakdown releases glucose units as
a.
glucose 6-phosphate
b.
glucose 1-phosphate
Correct Answer
c.
glucose
d.
glucose and glucose 6-phosphate
Step-by-Step AI Explanation
Verified Method
Glycogen phosphorylase catalyzes the phosphorolysis of $\alpha(1\rightarrow 4)$ glycosidic bonds in glycogen, releasing glucose units in the form of glucose 1-phosphate.
Q29
mcq
The $Na^+ / K^+$ ATPase pump is found on the plasma membrane of most animal cells, A mutation in the intrinsic phosphorylation site of the pump is most likely to affect.
a.
the outward movement of $Na^+$ only
b.
inward movement of $K^+$ only
c.
both the inward and outward movement of $K^+$ and $Na^+$
Correct Answer
d.
has no effect on pump activity but affects its stability
Step-by-Step AI Explanation
Verified Method
The $\text{Na}^+/\text{K}^+$ ATPase operates via a cyclical mechanism involving phosphorylation and dephosphorylation of a conserved aspartate residue. Phosphorylation drives the conformational change from the $E_1$ state (high affinity for $\text{Na}^+$) to the $E_2$ state (releasing $\text{Na}^+$ extracellularly and binding $\text{K}^+$). If the intrinsic phosphorylation site is mutated, the pump cannot complete this catalytic cycle, thereby preventing both the outward transport of $\text{Na}^+$ and the inward transport of $\text{K}^+$.
Q30
mcq
Fruit bats are known to harbour and spread several viruses that can infect other animals and human. Which one of the following viruses is NOT reported to spread by fruit bats ?
a.
Ebola
b.
Nipah
c.
SARS
d.
HIV
Correct Answer
Step-by-Step AI Explanation
Verified Method
Fruit bats are natural reservoirs for many zoonotic viruses, including Ebola virus (Filoviridae), Nipah virus (Henipavirus), and SARS-like coronaviruses. Human Immunodeficiency Virus (HIV) originated from simian immunodeficiency viruses (SIV) transmitted to humans from non-human primates (chimpanzees and sooty mangabeys) and is not spread by bats.
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Q31
mcq
In a type I hypersensitivity-mediated asthmatic response, which one of the following is thought to contribute significantly to the prolonged bronchospasm and build-up of mucous seen in asthmatics ?
a.
Thromboxane
b.
Leukotriene
c.
TGF$\beta$
d.
Chondroitin
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Q32
mcq
In a human cell line, a large fraction of double-strand DNA breaks are repaired by non-homologous end joining (NHEJ). An inhibitor of FLAP endonuclease will affect
a.
recruitment of DNA-dependent kinase
b.
gap trimming
c.
DNA unwinding
d.
pairing of micro-homology regions
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Q33
mcq
Sugar puckering in double stranded nucleic acids is exclusively
a.
C-$2'$ endo in double stranded DNA
b.
C-$3'$ endo in double stranded DNA
c.
C-$2'$ endo in double stranded RNA
d.
C-$3'$ endo in hybrid duplex with one strand as DNA and the other as RNA
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Q34
mcq
Eukarotic mRNAs are modified to possess a $5'$ cap structure. Which one of the following is an INCORRECT statement about the function of $5'$ cap structure ?
a.
It protects the mRNA from $5' \rightarrow 3'$ exoribonucleases attack
b.
It facilitates splicing of the nascent transcripts
c.
It protects the transcript from degradation by RNAse III family enzymes
d.
It facilitates attachment to 40S subunit of ribosome
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Q35
mcq
Which one of the following does NOT belong to human antimicrobial proteins and peptides at epithelial surface forming part of innate immunity ?
a.
Lactoferrin
b.
Defensin
c.
Calprotectin
d.
Vimentin
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Q36
mcq
Which one of the following best describes death-upon-detachment ?
a.
Necroptosis
b.
Anoikis
c.
Extravasation
d.
Metastasis
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Q37
mcq
Out of several gibberllins identified in plants, which one of the following is NOT bioactive ?
a.
$\text{GA}_1$
b.
$\text{GA}_3$
c.
$\text{GA}_4$
d.
$\text{GA}_5$
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Q38
mcq
Nitrogenase, a complex metal containing enzyme is involved in conversion of $\text{N}_2$ to $\text{NH}_3$. Which one of the following metals is NOT involved in the activity of nitrogenase ?
a.
Molybdenum (Mo)
b.
Iron (Fe)
c.
Vanadium (V)
d.
Cobalt (Co)
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Q39
mcq
Which one of the following agents cause relaxation of mesangial cells ?
a.
Histamine
b.
Thrombaxane $\text{A}_2$
c.
Norepinephrine
d.
Dopamine
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Q40
mcq
A patient comes to the hospital complaining of vomiting and diarrhoea. The doctor suggested that the patient take glucose and electrolyte solution orally. Which one of following membrane proteins is likely to be involved in rehydrating the patient ?
a.
Cystic fibrosis transmembrane regulator (CFTR)
b.
Sodium glucose transporter protein I (SGLT1)
c.
Insulin receptor protein (IRP)
d.
Sucrase-isomaltase protein (SIP)
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Q41
mcq
In certain plants, the mechanism where timing of anther dehiscence and stigma receptivity do not coincide to avoid self - pollination is called
a.
dichogamy
b.
herkogamy
c.
monoecy
d.
dioecy
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Q42
mcq
In \textit{Xenopus} embryos, $\beta$-catenin plays an important role the Doral/Ventral axis development. What would you expect if the endogenous glycogen synthase kinase 3 (GSK3) is knocked out by a dominant-negative form of GSK3 in the ventral cells of the early embryo ?
a.
Blocking of GSK3 on the ventral side has no effect. A normal embryo will form
b.
The resulting embryo will only have ventral sides
c.
A second axis will form
d.
The dorsal fate is suppressed
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Q43
mcq
Homeobox transcription factors (Hox proteins), play important roles in specifying whether a particular mesenchymal cell will become stylopod, zeugopod or autopod. Based on the expression patterns of these genes, a model was proposed wherein these Hox genes specify the identity of a limb region. What would be the observed phenotype for human homozygous for a \textit{HOXD13} mutation ?
a.
No zeugopod formation
b.
Abnormalities of the hands and feet wherein the digits fuse
c.
Deformities in stylopods
d.
No femur or patella formation
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Q44
mcq
Which one of the following describes the function of silicon in plants ?
a.
Constituent of amino acids
b.
Contributes to cell wall rigidity and elasticity
c.
Constituent of the photosynthesis reaction centre
d.
Maintenance of cell turgor and electro-neutrality
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Q45
mcq
Most of the plant disease resistance (R) gene products contain :
a.
G-Box domains
b.
Transcription repression domains
c.
Leucine-rich repeats
d.
Enzymatic activities
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Q46
mcq
Which one of the following DNA markers can be used to distinguish between a homozygote and a heterozygote ?
a.
RAPD
b.
AFLP
c.
RFLP
d.
ISSR
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Q47
mcq
Which one of the following is a fungal disease of plants ?
a.
Cucumber mosaic
b.
Fire blight of pear
c.
Crown gall
d.
Apple scab
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Q48
mcq
Which one of the following influenza A virus subtypes caused severe avian flu and was responsible for disease outbreak in the year 1997 in Hong Kong ?
a.
H1N1
b.
H7N7
c.
H3N2
d.
H5N1
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Q49
mcq
Which one is required for vitamin $\text{B}_{12}$ absorption in small intestine?
a.
Cobalophilin
b.
Hephaestin
c.
Hepcidin
d.
$\text{Na}^+$-cotransporter
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Q50
mcq
Which one is the correct sequence of events that takes place during phototransduction when light falls onto the retina ?
a.
Closure of $\text{Na}^+$ channels $\rightarrow$ activation of transducin $\rightarrow$ decreased release of glutamate $\rightarrow$ decrease in intracellular cGMP $\rightarrow$ structural changes in rhodopsin
b.
Decreased release of glutamate $\rightarrow$ structural changes in rhodophisn $\rightarrow$ activation of transducin $\rightarrow$ decrease in intracellular cGMP $\rightarrow$ closure of $\text{Na}^+$ channels
c.
Structural changes in rhodopsin $\rightarrow$ activation of transducin $\rightarrow$ decrease in intracellular cGMP $\rightarrow$ closure of $\text{Na}^+$ channels $\rightarrow$ decreased release of glutamate
d.
Decrease in intracellular cGMP $\rightarrow$ activation of transducin $\rightarrow$ decreased release of glutamate $\rightarrow$ structural changes in rhodopsin $\rightarrow$ closure of $\text{Na}^+$ channels
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Q51
mcq
A Lod score of 3 represents a Recombination Frequency (RF) that is
a.
3 times as likely as the hypothesis of no linkage
b.
30 times as likely as the hypothesis of no linkage
c.
100 times as likely as the hypothesis of no linkage
d.
1000 times as likely as the hypothesis of no linkage
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Q52
mcq
Assuming that the $A$, $B$, $C$ and $D$ genes are not linked, the probability of a progeny being $AaBbCcDd$ from a cross between $AABbCcDd$ and $aaBbCcDD$ parents will be
a.
$4/32$
b.
$3/16$
c.
$1/4$
d.
$3/32$
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Q53
mcq
The new born baby of a mother having blood group $\text{AB}, \text{Rh}^+$ and father having blood group $\text{O}, \text{Rh}^-$, got mixed with other babies in the hospital. The baby with which of the following blood groups is expected to be of the said couple ?
a.
$\text{O}, \text{Rh}^+$
b.
$\text{O}, \text{Rh}^-$
c.
$\text{AB}, \text{Rh}^-$
d.
$\text{B}, \text{Rh}^+$
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Q54
mcq
Which one of the following does NOT contribute to microevolutionary change ?
a.
Mutation
b.
Random drift
c.
Genetic drift
d.
Natural selection
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Q55
mcq
According to Hamilton's rule, altruistic behaviour can evolve when $\text{rb} > \text{c}$, where $\text{b}$ is the extra benefit gained by the recipient as a result of the altruistic act, $\text{c}$ is the cost to the actor arising from performing the altruistc act and $\text{r}$ is the relatedness between the :
a.
individual performing the altruistic act and the offspring of the recipient
b.
individual performing the altruistic act and the recipient
c.
recipient and the offspring of the individual performing the altruistic act
d.
individual performing the altruistic act and the members of its population
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Q56
mcq
Analyses of nucleotide sequences of ribosomal RNA (rRNA) are particularly useful for evolutionary studies of living organisms because of the following reasons EXCEPT
a.
rRNA is evolutionarily ancient
b.
no free-living organism lacks rRNA
c.
rRNA, since critical for translation, can undergo lateral transfer amongst distant species
d.
rRNA has evolved slowly over geological time
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Q57
mcq
Which one of the following is the most appropriate definition of 'Gene Pyramiding' in plants ?
a.
Introducing different genes for resistance to a specific pest in different genotypes
b.
Introducing a single gene for resistance to a particular pest in different genotypes
c.
Introducing different genes for resistance to a single pest in a single genotype
d.
Introducing a single gene for resistance to multiple pests in different genotypes
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Q58
mcq
Depicted below is a phylogenetic tree of selected taxa :
Based on the above, which one of the following statements is correct ?
a.
Group X is monophyletic and Group Y is polyphyletic
b.
Group X is paraphyletic and Group Y is monophyletic
c.
Both Group X and Y are monophyletic
d.
Group X is monophyletic and Group Y is paraphyletic
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Q59
mcq
Which of the following describes the identification features of non-poisonous snakes ?
a.
Cylindrical tail and small belly scales
b.
Cylindrical tail, broad transverse belly scales and 4th infralabial scale is the largest
c.
Flat tail, broad transverse scales and 3rd supralabial scale touches eye and nose
d.
Cylindrical tail, broad transverse belly scales and a loreal pit between eye and nostril
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Q60
mcq
A road is constructed through a wet tropical forest, following which the population of a species of forest butterfly declines. Which of the following is NOT a possible explanation for the road causing a decline in the forest butterfly population ?
a.
Road facilitates immigration of gap-loving species which compete with the forest species
b.
Road facilitates increased movement of the forest butterfly within the forest, which reduces genetic diversity
c.
Road internally fragments the habitat and negatively affects important micro-habitat conditions for the forest butterfly.
d.
Road facilitates invasion by non-native plants that displace native host and nectar plants of the forest butterfly.
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Q61
mcq
Which one of the following statements regarding normal distribution is NOT correct ?
a.
It is symmetric around the mean
b.
It is symmetric around the median
c.
It is symmetric around the variance
d.
It is symmetric around the mode
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Q62
mcq
Tropical regions may have more species diversity because of the following possible reasons, EXCEPT
a.
tropical regions have had more time to diversify under relatively stable climatic conditions than temperate regions
b.
tropical regions have high spatial heterogeneity
c.
greater biological competition in the tropics lead to narrower niche
d.
lower biological intensity in the tropics allows survival of more prey species
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Q63
mcq
Which one of the following statements is correct ?
a.
Ectomycorrhizal associations predominantly reduce phosphorus limitation, and endo-mycorrhizal associations reduce both nitrogen and phosphorus limitation
b.
Endomycorrhizal associations predominantly reduce phosphorus limitation, and ectomycorrhizal associations reduce both nitrogen and phosphours limitation
c.
Ecto-and endo-mycorrhizal associations do not reduce nitrogen and phosphours limitation
d.
Ecto-and endo-mycorrhizal associations are able to reduce only phosphorus limitation
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Q64
mcq
Which one of the following statements is correct for the process of speciation ?
a.
Allopatric speciation occurs between adjacent populations
b.
Parapartic speciation may occur between geographically separated populations
c.
Sympatric speciation occurs within one continuously distributed population
d.
Sympatric speciation occurs when continuously distributed populations are fragmented
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Q65
mcq
Orientation of a cloned DNA fragment (gene) in a plasmid vector can be checked by
a.
PCR using two gene-specific primers
b.
Restriction digestion with an enzyme that has a single restriction site within the cloned gene and none in the vector
c.
PCR using a combination of one gene-specific primer and one vector-specific primer
d.
Restriction digestion with an enzyme that has two restriction sites within the vector sequence and none in the cloned gene
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Q66
mcq
The emission maximum of tryptophan fluorescence in a protein is $\sim 335\text{ nm}$. This suggests that tryptophan
a.
is in a hydrophobic environment
b.
occurs in a helical segment
c.
has proximal cysteine residues
d.
is oxidized
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Q67
mcq
To test the impact of cAMP on protein kinase A conformation in cells, an investigator made FRET biosensor by fusing two fluorescent proteins at the N-and C-terminus of protein kinase A. In the absence of cAMP in the cellular milieu, no FRET signal was detected. However, upon cAMP addition, a strong emission at 530 nm was observed. What could be the best configuration of fluorophores that were used by the investigator ?
a.
Green fluorescent protein (GFP) and Red fluorescent protein (RFP)
b.
CYAN fluorescent protein (CFP) and Yellow fluorescent protein (YFP)
c.
Yellow fluorescent protein (YFP) and Red fluorescent protein (RFP)
d.
Red fluorescent protein (RFP) and CYAN fluorescent protein (CFP)
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Q68
mcq
In bioremediation by microorganisms detailed below, choose the INCORRECT option?
a.
The organic contaminants provide a source of carbon
b.
The bacteria do not get net energy by degrading contaminants
c.
Bacteria can produce oxidized or reduced species that can cause metals to precipitate
d.
Bacteria act on contaminants by aerobic and anaerobic respiration
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Q69
mcq
A multimeric protein when run on an SDS gel showed 2 bands at 20 kDa and 40 kDa. However, when the protein was run on a native gel, it showed a single band at 120 kDa. The native form of the protein would be
a.
homotrimer
b.
heterotctramer
c.
heterodimer
d.
heterotrimer
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Q70
mcq
A solution contains NADH and NAD+, both at 0.1 mM concentration. If NADH has a molar extinction coefficient of 6220 and that of NAD+ is negligible, the optical density measured in a cuvette of 5 mm path length will be
a.
0.62
b.
0.062
c.
0.31
d.
0.031
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Q71
mcq
In an experiment, the student has infected mammalian host cell with cytoplasmic RNA virus. The virus growth was monitored by measuring the intracellular viral RNA at different time intervals. It was observed that viral RNA titre progressively went down with time, particularly 12 hours post infection. Following are few possibilities which can explain this observation.
A. The virus infection triggered upregulation of miRNAs that might have downregulated the host factor critical for viral RNA replication.
B. The virus might encode miRNAs that regulate (inhibits) its own replication.
C. One of the viral proteins inhibits replication of the viral RNA to restrict rapid proliferation.
D. Viral RNA goes to nucleus with time and thus not detectable in the cytoplasm 12 hour post infection.
Which one of the following options has all correct statements ?
a.
A, B and C
b.
A, C and D
c.
A, B and D
d.
B, C and D
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Q72
mcq
Irrespective of the chromosomal configuration, a single X-chromosome remains active in all diploid human somatic cell lines. Which one of the following mechanisms best accounts for the above phenomenon ?
a.
A maternally inherited X-chromosome is developmentally programmed to remain active by avoiding DNA methylation.
b.
Chromosome specific expression and binding of rox1 to one of the X-chromosomes protects it from Xist mediated silencing.
c.
The $T\text{-}six$ gene produces just enough of the Xist antisense RNA to block one Xic locus.
d.
A cell produces just enough of the blocking factor to block one Xic locus.
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Q73
mcq
In eukaryotic cells, replication initiation from a replication origin occurs only once per cell cycle and S-phase CDKs play a vital role in the regulation of DNA replication. In budding yeast a protein complex known as the origin recognition complex (ORC) is associated with DNA replication origin during $\text{G}_1$ : however, origins fire only once at the beginning of S-phase. DNA replication does not start in $\text{G}_1$ because :
A. MCM helicases are inactive in $\text{G}_1$.
B. Spindle checkpoint is active in $\text{G}_1$.
C. DNA polymerase is not recruited in $\text{G}_1$.
D. ORC and initiation factors Cdc6 and Cdt1 do not recruit MCM helices to the site of replication initiation in $\text{G}_1$. Which of the above statements are correct ?
a.
A and B
b.
A and C
c.
B and C
d.
B and D
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Q74
mcq
Measurements of the rate of actin treadmilling *in vivo* show that it can be several times higher than can be achieved with pure actin *in vitro*. The treadmilling in vitro can be enhanced by providing.
A. profilin that binds G-actin on the site opposite the nucleotide binding cleft.
B. cofilin binds specifically to the ADP containing F-actin and destabilizes the actin filament.
C. buffer with ATP and low levels of cations.
D. buffer with ADP and low levels of cations.
Which of the above statements are correct ?
a.
A and D
b.
A and C
c.
C and D
d.
A and B
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Q75
mcq
Equal volumes of pH 4.0 and pH 10.0 solutions are mixed. What will be the approximate pH of the final solution ?
a.
7.0
b.
5.0
c.
6.0
d.
4.0
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Q76
mcq
The inborn error of amino acid metabolism, alkaptonuria, is due to the lack of one of the following enzymes :
a.
Fumaryl acetoacetate hydrolase
b.
$\alpha$ - ketoacid decarboxylase
c.
Homogentisate oxidase
d.
p-hydroxyphenylpyruvate dehydroxylase
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Q77
mcq
The structure of a protein with 100 residues was determined by X-ray analysis at atomic resolution and NMR spectroscopy. The following observations are possible.
A. The dihedral angles determined from the X-ray structure and NMR will be identical.
B. The dihedral angles determined from the X-ray structure will be more accurate.
C. $\beta$ - turns can be determined only by NMR.
D. $\beta$ - sheets can be more accurately determined from the X-ray structure.
Indicate the combination with ALL correct ansers
a.
A and C
b.
B and D
c.
B and C
d.
A and D
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Q78
mcq
The different arms in the tRNA structure are shown in Column A. The specific signatures associated with the different arms are shown in Column B.
\begin{tabular}{|l|l|l|l|}
\hline
& Column - A & & Column - B \\
\hline
A. & Acceptor arm & (i) & Dihydrouridine \\
\hline
B. & Anticodon arm & (ii) & 7 bp stem and CCA sequence \\
\hline
C. & $\text{T}\psi\text{C}$ arm & (iii) & 5 bp stem \\
\hline
D. & D - arm & (iv) & Pseudouridine \\
\hline
\end{tabular}
Choose the correct matches from the following :
a.
A - (ii), B - (iv), C - (i), D - (iii)
b.
A - (i), B - (iii), C - (iv), D - (ii)
c.
A - (iv), B - (i), C - (ii), D - (iii)
d.
A - (ii), B - (iii), C - (iv), D - (i)
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Q79
mcq
Some coenzymes that serve as transient carriers of specific chemical group are shown below :
\begin{tabular}{|l|l|l|l|}
\hline
& Coenzyme & & Chemical group transferred \\
\hline
A. & Coenzyme A & (i) & Electrons \\
\hline
B. & Flavin adenine dinucleotide & (ii) & Acyl groups \\
\hline
C. & Pyridoxal phosphate & (iii) & Hydride ions \\
\hline
D. & Nicotinamide adenine dinucleotide & (iv) & Amino groups \\
\hline
\end{tabular}
Choose the combination with all correct matches
a.
A - (i), B - (ii), C - (iii), D - (iv)
b.
A - (ii), B - (i), C - (iv), D - (iii)
c.
A - (iii), B - (iv), C - (ii), D - (i)
d.
A - (iv), B - (iii), C - (i), D - (ii)
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Q80
mcq
Thermodynamics of protein folding is depicted as a free energy funnel below :
Given below are regions in the diagram (Colum X) and their representation (Column Y)
Choose the option that shows all correct matches
a.
A - (ii), B - (iii), C - (iv), D - (i)
b.
A - (i), B - (ii), C - (iii), D - (iv)
c.
A - (iii), B - (iv), C - (ii), D - (i)
d.
A - (iv), B - (i), C - (ii), D - (iii)
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Q81
mcq
Table below shows the list of organelles (Colum A) and the signals (Colum B) that target proteins to the organelle.
Choose the option that shown all correct matches
a.
A - (ii), B - (iii), C - (iv), D - (i)
b.
A - (ii), B - (iv), C - (iii), D - (i)
c.
A - (iv), B - (iii), C - (i), D - (ii)
d.
A - (iv), B - (iii), C - (ii), D - (i)
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Q82
mcq
Following statements are made about chromatin remodelling in human cells :
A. Local chromatin conformation may play more important role than the local DNA sequence of the promoter.
B. Histones in nucleosome can undergo many different covalent modification, which in turn, alter the chromatin architecture locally.
C. Chromatin remodelling is a developmentally regulated passive process which does not required ATP.
D. Several histone variants exist, which replace the standard histones in specific types of chromatin.
Select the option that has the combination of all correct answer.
a.
A, C, D
b.
A, B, C
c.
A, B, D
d.
B, C, D
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Q83
mcq
The extracellular matrix contains a number of non-collagen proteins that typically have multiple domains, each with specific binding sites for other matrix molecules and cell surface receptors. These proteins therefore contribute to both organizing the matrix and helping cells attach to it. The most well characterized matrix protein of this kind is fibronectin. Which one of the following characteristics is NOT TRUE for fibronectin ?
a.
It is a large glycoprotein found in all vertebrates and important for many cell-matrix interactions.
b.
It is composed of three polypeptides that are disulfide bonded into a crosslink structure.
c.
In human genome, there is only one fibronectin gene containing about 50 exons, but the transcripts can be spliced in different ways to produce many different fibronectin isoforms.
d.
Fibronectin binds to integrin through an RGD motif. Even very short peptide containing RGD sequence can inhibit attachment of cells to fibronectin matrix.
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Q84
mcq
Following are the list of some cellular receptors (Column X) and with possible functional characteristics (Column Y) :
\begin{tabular}{|l|l|}
\hline
Column X & Column Y \\
\hline
A. Asialoglycoprotein receptor & (i) Intracellular high affinity receptor which upon binding with ligand acts as transcription factor and binds to DNA. \\
\hline
B. Transferrin receptor & (ii) Extracellular receptor which upon binding with ligand is subjected to endocytosis. Receptor - ligand complex accumulates in acidic endosomes / CURL (compartment of uncoupling of receptor and ligand), delivers the cargo, receptor - ligand complex recycles back to cell surface and the ligand disassociates. \\
\hline
C. Steroid receptor & (iii) Extracellular receptor which upon binding with ligand is subjected to endocytosis. Receptor - ligand complex accumulates in acidic endosomes / CURL, ligand gets dissociated, transfers to lysosomes and the receptor recycles back to cell surface. \\
\hline
\end{tabular}
Which one of the following is the correct match ?
a.
A - (i), B - (ii), C - (iii)
b.
A - (ii), B - (iii), C - (i)
c.
A - (iii), B - (ii), C - (i)
d.
A - (i), B - (iii), C - (ii)
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Q85
mcq
In a laboratory experiment it was observed that both 'Virus A' and 'Virus B' could infect a mammalian host cells, when infected individually. Interestingly, if the cells were first infected with 'Virus A' (with large MOI), Virus B (with large MOI) is added first followed by Virus A, both the virus can infect the cells. However, infection with 'Virus A' was found to be in lesser extent. Considering X and Y are the receptors/co-receptors which may be involved for the virus entry, following are few possibilities that can explain the observation.
A. 'Virus A' uses 'X' as receptor and Y as co-receptor.
B. 'Virus B' uses exclusively 'Y' as receptor for entry.
C. Both 'Virus A' and 'Virus B' need X as receptor.
Choose the option with all correct statements.
a.
A, B and C
b.
A and B
c.
B and C
d.
A and C
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Q86
mcq
While testing the effect of several potent anti-cancer compounds on cycling human oral cancer cells, a student observed that a percentage of cells showed dose-dependent cell death after 12 hours of drug treatment. However, the remaining cells repopulated the culture dish once the compounds were removed and the cells were cultured in complete medium. The student made the following assumptions :
A. Not all cells were equally affected by the compounds as they were not synchronized before treatment.
B. The compound selectively killed cells which were in $\text{G}_0$ phase.
C. The cancer stem cells were impervious to the effects of the compounds and thereforerepopulated the culture.
D. The cancer cells differentiated into a mesenchymal phenotype and grew in fresh culture medium containing inhibitors of epithelial-to-mesenchymal transition (EMT).
Which one of following combination of assumptions would best justify the results ?
a.
B and C
b.
A and C
c.
B and D
d.
A and B
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Q87
mcq
When 8-cell embryo of tunicates is separated into 4 blastomere pairs and allowed to grow independently in culture medium, then each blastomere pair can form most of the cell types; however, cells for nervous system are not developed. The following statements are formed from the above observations :
A. Nervous system development demonstrated autonomous specification.
B. The other tissue types are formed due to conditional specification.
C. All the tissue types, except nervous tissues that developed, demonstrated autonomous specification.
D. Nervous system development demonstrated conditional specification.
The correct combination of statements that explains the above result is :
a.
A and B
b.
B and C
c.
C and D
d.
A and D
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Q88
mcq
In a strain of *E.coli*, a fusion between the *lac* and *trp* operon took place and the new locus structure is shown below. The strain lacks the wild-type *trp* operon.
Given below are some of the potential scenarios :
A. Tryptophan will be synthesized in a medium containing lactose and tryptophan.
B. Tryptophan synthesis will be repressed in a medium containing glucose.
C. Tryptophan synthesis will take place only in the absence of sufficient tryptophan in the medium.
Choose the option that correctly describes the behaviours of the fusion operon.
a.
A and B
b.
A and C
c.
C only
d.
B and C
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Q89
mcq
Following statements have been made about removal of supercoiling produced by DNA unwinding at the replication fork :
A. Accumulation of supercoils is the result of DNA helicase activity during unwinding of DNA.
B. Problem of DNA supercoiling is valid only for circular chromosomes of bacteria and not for the linear chromosomes.
C. Supercoiling of DNA is removed by topoisomerases by breaking either one or both strands of DNA on the unreplicated DNA in front of replication fork.
D. Both topoisomerase I and topoisomerase II can remove positive supercoiling during replication.
Which one of the following options has all correct statements ?
a.
A, B, C
b.
A, B, D
c.
A, C, D
d.
B, C, D
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Q90
mcq
Phosphorylation of the $\alpha-$subunit of eIF2 at Ser51 position in *Saccharomyces cerevisiae* leads to sequestration of eIF2B, a guanosine exchange factor. This phenomenon is
a.
known to activate translation of the capped mRNAs in the cytosol
b.
known to activate translation of many key mRNAs possessing short ORFs (uORFs) in the mRNA sequence that precedes the main ORF
c.
an essential requirement for translation of IRES containing mRNAs
d.
an essential requirement for the transport of mature mRNAs out of the nucleus.
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Q91
mcq
*E.coli* mutants isolated from a genetic screen showed following classes of mutations.
A. Point mutations in *lacI*.
B. Deletions immediately downstream of the transcription start site of the *lacZYA* mRNA.
C. Duplications of part or whole of *lacY*.
D. Duplications of part or whole of *lacA*.
Choose the option which is likely to result in constitutive expression of the *lac* operon?
a.
Both A and B
b.
Both B and C
c.
Both C and D
d.
only A
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Q92
mcq
For *Escherichia coli* chromosomal DNA replication, which one of the following statements is true ?
a.
DNA polymerase I is the main polymerase required for DNA replication
b.
DNA polymerase I though identified originally by Kornberg as the one responsible for replication, in not important for the DNA replication process
c.
Requirement of DNA polymerase I is in the context of removal of RNA primer needed for DNA synthesis, and then fill in the same will DNA equivalent
d.
DNA polymerase I is the primary enzyme for error prone DNA synthesis in response to SOS
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Q93
mcq
Following observations were made about variations among genomes of eukaryotic organisms :
A. Single nucleotide polymorphisms are the numerically most abundant type of genetic variants.
B. Both, interspersed and tandem repeated sequences can show polymorphic variation.
C. Mitotic recombination between mispaired repeats causes change in copy number and generates minisatellite diversity in population.
D. Smaller variable segments in the genome can be identified by paired end mapping technique.
Select the option with all correct statements.
a.
A, B, C
b.
A, C, D
c.
B, C, D
d.
A, B, D
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Q94
mcq
There are number of specific T cell surface molecules involved in various functions of adaptive immune response. Column X represents a list T cell surface molecules and Column Y with the possible functional characteristics.
\begin{tabular}{|l|l|}
\hline
Column X & Column Y \\
\hline
A. T cell receptor & (i) binds to CD40 on B cells and APCs and \\
& triggers activation of APCs and activation / \\
& differentiation of B cells. \\
\hline
B. CD28 & (ii) binds to MHC class I molecules and \\
& restricts T cytotoxic cells to recognizing \\
& only peptide presented on MHC class I. \\
\hline
C. CD8 & (iii) binds to $\text{B7}-1$, $2$ or $\text{CD80}/86$ on B \\
& cells and APCs, which triggers T cell \\
& activation. \\
\hline
D. CD154 & (iv) consists of two polypeptide chains $\alpha$ and \\
& $\beta$ and some consists of polypeptide chains \\
& $\gamma$ and $\delta$. \\
\hline
\end{tabular}
Which of the following option has all correct matches ?
a.
A - (i), B - (ii), C - (iii), D - (iv)
b.
A - (iv), B - (i), C - (ii), D - (iii)
c.
A - (iii), B - (iv), C - (i), D - (ii)
d.
A - (iv), B - (iii), C - (ii), D - (i)
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Q95
mcq
In an experiment it was observed that a protein was unregulated in the cancer tissues (compared to control tissues) that showed correlation with disease progression. Following are a few possibilities which can explain the above observation.
A. A mutation could be located in the 3'UTR of the corresponding mRNA at a miRNA binding site.
B. A mutation changes the conformation of the protein, resulting in its better stability.
C. A mutation in the corresponding mRNA promotes ribosome read-through of the termination codon resulting in increased synthesis of the protein.
D. A mutation in the corresponding mRNA increased the stability of the RNA due to change in secondary structure.
Which one of the following combinations represents the most likely explanations ?
a.
A, B and C
b.
B, C and D
c.
C, D and A
d.
A, B and D
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Q96
mcq
Following are certain statements with regard to plant respiration :
A. Metabolism of glucose into pyruvate through glycolysis generates NADH and not NADPH.
B. Metabolism of glucose through oxidative pentose phosphate cycle does not produce NADPH.
C. Cyanide forms a complex with haem iron of cytochrome oxidase leading to prevention of change in valency, which in turn stops electron transport in the respiratory chain.
D. Alternative oxidase is insensitive to cyanide and has higher Km than that of cytochrome oxidase.
Which one of the following combinations is correct ?
a.
A, B and C
b.
B, C and D
c.
B and D
d.
A, C and D
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Q97
mcq
Blue light receptor cry1 binds to COP1 and SPA1 complex by interacting with C-terminal region of cry1 (CCT) in a light dependent manner and regulates photomorphogenesis via transcription factor HY5. Read the following statements :
A. cry1 binds to COP1 and SPA1 complex leading to degradation of HY5.
B. cry1 binds to COP1 and SPA1 complex and prevents degradation of HY5.
C. CCT is overexpressed and the plants are kept in dark.
D. CCT is overexpressed and the plants are kept in light.
Which of the following combination of above statements will result in photo-morphogenesis ?
a.
Only A
b.
Only B
c.
A, B and C
d.
B, C and D
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Q98
mcq
After absorbing light, chlorophyll molecules in green plants exist in singlet and triplet states. Following are certain statements on singlet and triplet states of chlorophyll molecules :
A. Singlet state is short lived compared to triplet state.
B. Singlet state is long lived compared to triplet state.
C. Singlet state contains electrons with anti-parallel spins while triplet state has electrons with parallel spins.
D. Singlet state contains electrons with parallel spins while triplet state has electrons with anti-parallel spins.
Which one of the following combinations is correct ?
a.
A and B
b.
B and C
c.
A and C
d.
B and D
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Q99
mcq
Only members of the plant kingdom and many bacteria have capability of biological nitrogen reduction. In this regard, following statements are given :
A. Nitrogen is normally taken by the plant in their fully oxidized form but needs to be reduced before incorporation in organic molecules.
B. Conversion of oxidized nitrogen into reduced nitrogen needs energy in the form of NAD(P).
C. The metal associated with the enzyme nitrate reductase is Magnesium.
D. Nitrate reduction takes place in the cytoplasm, whereas nitrite reduction takes place in chloroplast matrix.
Which one of the following combinations of the above statements is correct ?
a.
A and C
b.
A, B and C
c.
B and D
d.
A and D
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Q100
mcq
During interaction with host, phytopathogens are known to deliver effector proteins directly into the host cells. The following statements were made regarding the role of these effector protein.
A. May promote pathogen virulence.
B. May elicit a virulence response.
C. May suppress defense response.
D. May promote plant growth.
Which one of the following combinations of the above statements is correct ?
a.
A, B and D
b.
A, C and D
c.
A, B and C
d.
B, C and D
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Q101
mcq
During wing development in chick, if Apical Ectodermal Ridge (AER) is removed, the limb development ceases, on the other hand placing leg mesenchyme directly beneath the wing AER, distal hindimb structures develop at the end of the wing, and if limb mesenchyme is replaced by non-limb mesenchyme beneath AER, the AER regresses. This may demonstrate that :
A. the limb mesenchyme cells induce and sustain AER.
B. the mesenchyme cells specify the type : wing or limb. C. the AER is responsible for specifying the type : wing or limb.
D. the AER is responsible for sustained outgrowth and development of the limb.
E. the AER does not specify the type : wing or limb.
Which combination of above statements is demonstrated by the experiment ?
a.
A, B, C and D only
b.
A, B, D and E only
c.
C, D and E only
d.
A and E only
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Q102
mcq
The following statements regarding the generation of dorsal/ventral axis in Drosophila was made:
A. Gurken protein moves along with the oocyte nucleus and signals follicle cells to adopt the ventral fate.
B. Maternal deficiencies of either the gurken or torpedo gene cause ventralization of the embryo.
C. Gurken is active only in the oocyte and Tropedo is active only in the somatic follicle cells.
D. The Pipe protein is made in the dorsal follicle cells.
E. The highest concentration of Dorsal is in the dorsal cell nuclei, which becomes the mesoderm.
Which one of the following combination of the above statements is true?
a.
A and E
b.
C and D
c.
B and C
d.
B and E
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Q103
mcq
A specialized area of teratogenesis involves the misregulation of the endocrine system. Which one of the following statements regarding endocrine disruptors is true ?
a.
They can act as antagonist and inhibit the binding of a hormone to its receptors or block the synthesis of a hormone.
b.
They do not affect the synthesis, elimination or transportation of a hormone in the body.
c.
They do not mimic the effect of natural hormones.
d.
Low does exposure to endocrine disruptors is not sufficient to produce significant disabilities later in life.
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Q104
mcq
Given below are statements related to different aspects of plant growth and development.
A. Leaf longevity is increased in ethylene-insensitive mutants etr1-1 and ein2 of Arabidopsis.
B. Programmed cell death (PCD) is responsible for the formation of prickles, thorns and spines in plants.
C. Senescence and PCD occur only in the development of vegetative tissues and does not occur in reproductive tissues.
D. Redifferentiation of organelles is an integral component during initial stages of senescence in plants.
Which one of following represents the combination of all correct statements ?
a.
A, C and D
b.
B and C
c.
A, B and D
d.
C and A
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Q105
mcq
The following demonstrates proposed functions of different genes which determine the decision to become either trophoblast or inner cell mass (ICM) blastomere during early mammalian development :
Based on the above figure, which one of the following assumptions is correct ?
a.
The interplay between Cdx2 and Oct4 can influence the formation of ICM
b.
The ICM would form even if expression of Oct4 was inhibited
c.
YAP and TEAD4 are upstream components of Cdx2 and can be inhibited by Nanog
d.
The expression of Stat3 is optional for maintaining pluripotency of the ICM
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Q106
mcq
Jasmonate is known to inhibit root growth while auxin facilitates root growth. Upon infection with pathogenic bacteria that produce coronatine, one may expect the following in plants:
A. Upregulation of COI-1 gene and inhibition of root growth.
B. Upregulation of Auxl-1 gene and inhibition of root growth.
C. Inhibition of Auxl-1 gene and promotion of root growth.
D. Inhibition of COI-1 gene and promotion of root growth.
Which one of the following is correct ?
a.
A, B and C
b.
Only A
c.
Only B
d.
Only C
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Q107
mcq
A family was examined for a given trait which is represented in the pedigree shown below. Further, the degree of expression of the trait is highly variable among members of the family; some are only slightly affected while others developed severe symptoms at an early age.
The following statement are made to explain the pattern of inheritance shown in the pedigree :
A. X-linked dominant mutation.
B. X-linked recessive mutation.
C. Mitochondrial inheritance.
D. Variable expression can be due to heteroplasty.
The best possible explanation for this inheritance is
a.
A and D
b.
C and D
c.
B only
d.
A only
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Q108
mcq
The location of six deletions (shown as solid line underneath the chromosome) has been mapped to the *Drosophila* chromosome as shown in the diagram given below :
Recessive mutations a, b, c, d, e, f and g are known to be located in the region of deletions, but the order of mutations on the chromosome is not known. When flies homozygous for the recessive mutations are crossed with flies homozygous for the deletion, the following results were obtained, where the letter 'm' represents a mutant phenotype and '+' represents the wild type. The relative order of the seven mutant genes on chromosome is :
a.
b c e a f g d
b.
b c d f g e a
c.
b c d e a f g
d.
c d e a g f b
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Q109
mcq
In the following pedigree, individuals with shaded circle or shaded square show presence of a recessive autosomal trait.
The calculated risk of occurrence of this trait for III-1 is
a.
1/2
b.
1/4
c.
1/8
d.
1/3
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Q110
mcq
During the course of vertebrate evolution, the jaw bones got modified into three ear ossicles in mammals. Which one of the following is a correct match of ear ossicle and its ancestral jaw bone ?
a.
Stapes - Articular, Incus - Hyomandibular, Malleus - Quadrate
b.
Stapes - Quadrate, Incus - Articular, Malleus - Hyomandibular
c.
Stapes - Quadrate, Incus - Hyomandibular, Malleus - Articular
d.
Stapes - Hyomandibular, Incus - Quadrate, Malleus - Articular
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Q111
mcq
The $\text{CO}_2$ dissociation curves of oxygenated and deoxygenated blood are given along with dissolved $\text{CO}_2$ below :
Following are the statements deduced from the curves above and/or based on the knowledge about $\text{CO}_2$ transport, which may or may not be correct :
A. The deoxygenated haemoglobin has greater affinity for $\text{CO}_2$ than oxygenated haemoglobin.
B. The deoxygenated haemoglobin does not bind with free $\text{H}^+$ ions released during the formation of $\text{HCO}_3^-$ from $\text{CO}_2$. C. The haemoglobin saturation with $\text{O}_2$ has no effect on $\text{CO}_2$ dissociation curve.
D. $\text{O}_2$ and $\text{CO}_2$ bind to haemoglobin at different sites.
Which of the following options represents a combination of all correct statements ?
a.
A and B
b.
B and C
c.
C and D
d.
A and D
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Q112
mcq
Given below are the different intervals/durations of electrocardiogram of a human subject (column A) and the events in heart during the process (column B).
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{COLUMN A} & \multicolumn{2}{|c|}{COLUMN B} \\
\hline
A. & PR interval & (i) & Ventricular action potential \\
\hline
B. & QRS duration & (ii) & Atrioventricular conduction \\
\hline
C. & QT interval & (iii) & Ventricular depolarization \\
\hline
D. & ST interval & (iv) & Plateau portion of the ventricular action potential \\
\hline
\end{tabular}
Which one of the following options is a correct match of entries in columns A and B ?
a.
A - (i), B - (iv), C - (ii), D - (iii)
b.
A - (ii), B - (iii), C - (i), D - (iv)
c.
A - (iv), B - (ii), C - (iii), D - (i)
d.
A - (iii), B - (i), C - (iv), D - (ii)
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Q113
mcq
The pathway of synthesis of aldosterone in zona glomerulosa along with the intracellular locations is shown below :
The enzymes below are required for different steps of synthesis of aldosterone :
\begin{tabular}{|l|l|}
\hline
i & 21-Hydroxylase \\
\hline
ii & P450 side chain cleavage enzyme \\
\hline
iii & $3\beta$-Hydroxy steroid dehydrogenase \\
\hline
\end{tabular}
Which one of the following options represents correct matches for A, B and C ?
a.
A - i, B - ii, C - iii
b.
A - iii, B - i, C - ii
c.
A - ii, B - iii, C - i
d.
A - ii, B - i, C - iii
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Q114
mcq
Given below is a figure of pro-opiomelanocortin (POMC) polypeptide and its cleavage products (marked as A, B, C, D) which have different hormonal activities. The names of the cleaved products obtained from POMC are shown in the table below the diagram.
\begin{tabular}{|l|l|}
\hline
i & Adrenocorticotropic hormone \\
\hline
ii & $\beta$-lipotropin \\
\hline
iii & $\alpha$-melanocyte-stimulating hormone \\
\hline
iv & $\beta$-endotropin \\
\hline
\end{tabular}
Which one of the following options represents A, B, C and D correctly ?
a.
A - (i), B - (ii), C - (iii), D - (iv)
b.
A - (ii), B - (iii), C - (i), D - (iv)
c.
A - (i), B - (iv), C - (iii), D - (ii)
d.
A - (iii), B - (ii), C - (iv), D - (i)
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Q115
mcq
During prolonged illumination, rhodopsin is desensitized which leads to the termination of visual response. The associated proteins (column A) and their effects (column B) are given below :
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{Column A} & \multicolumn{2}{c|}{Column B} \\
\hline
A. & Phosphorylated opsin & (i) & Phosphorylates opsin \\
\hline
B. & Rhodopsin kinase & (ii) & Binds to phosphorylated opsin \\
\hline
C. & Arrestin & (iii) & Decreases activation of transducin \\
\hline
D. & Phosphatase & (iv) & Reverses the termination process \\
\hline
\end{tabular}
Which one of the matched combinations is correct ?
a.
A - (iv), B - (ii), C - (i), D - (iii)
b.
A - (ii), B - (iii), C - (iv), D - (i)
c.
A - (iii), B - (i), C - (ii), D - (iv)
d.
A - (ii), B - (iv), C - (iii), D - (i)
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Q116
mcq
Estrus cycle in rats is controlled by pituitary and gonadal hormones. While treating a set of rats with vitamin D, a student accidentally injected the rats with an inhibitor of $17\alpha$-hydroxypregnenolone and checked vaginal smear for 10 consecutive days.
Which one of the following observations is correct ?
a.
The smears showed well formed nucleated epithelial cells throughout the period
b.
The smears initially showed normal estrus stage but eventually entered a prolonged diestrus stage
c.
The smears showed leukocytes and few epithelial cells
d.
The cells showed metestrus for 3 days and then returned to the proestrus stage
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Q117
mcq
Centromere positions can be mapped in linear tetrads in some fungi, A cross was made between two strains $a\ b$ and $a\ b$ and 100 linear tetraads were analysed. The genes $a$ and $b$ are located on two arms of the chromosome. The tetrads were divided into 5 classes as shown below.
\begin{tabular}{|l|l|l|l|l|l|}
\hline
Class & 1 & 2 & 3 & 4 & 5 \\
\hline
& $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ \\
\hline
& $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ \\
\hline
& $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ \\
\hline
& $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ & $a\ b$ \\
\hline
Linear tetrads & 15 & 29 & 52 & 2 & 2 \\
\hline
\end{tabular}
Based on the above observation, the following conclusions were drawn :
A. Class 1 is a result of a cross over between ‘a’ and the centromere.
B. Class 2 is a result of a double crossover involving 3 strands between ‘a’ and the centromere.
C. Class 5 is a result of a double crossover between ‘a’ - centromere, and ‘b’ involving three strands.
D. Class 4 is a result of a double crossover involving all the 4 strands
Which one of the following options represents all correct statements ?
a.
A and B
b.
A and C
c.
B and D
d.
C and D
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Q118
mcq
Two yellow mice with straight hair were crossed and the following progeny was obtained :
$1/2$ yellow, straight hair
$1/6$ yellow, fuzzy hair
$1/4$ gray, straight hair
$1/12$ gray, fuzzy hair
In order to provide genetic explanation for the results and assign genotypes to the parents and progeny of this cross, the following statements were given :
A. The $6 : 2 : 3 : 1$ ratio obtained here indicates recessive epistasis.
B. The cross concerns two independent characteristics - body colour and type of hair.
C. The deviation of dihybrid ratio from $9 : 3 : 3 : 1$ to $6 : 2 : 3 : 1$ may be due to one of the genes being a recessive lethal.
D. The lethal allele is associated with straight hair. The most appropriate combination of statements of provide genetic explanation for this result is :
a.
B and C
b.
A only
c.
B, C and D
d.
A, C and D
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Q119
mcq
Birds in a population show two foraging phenotypes, A and B. Birds of phenotype A search, attack and capture prey while birds of phenotype B steal prey from birds of phenotype A. A and B are maintained in the population through negative frequency-dependent selection. The graph below shows the fitness of A (broken line) and B (solid line) at different relative frequencies of A (frequency of B = $1$ - frequency of A).
Which of the following statements does the graph support ?
a.
A outcompetes B; at equilibrium, A goes to fixation
b.
B outcompetes A; at equilibrium, B goes to fixation
c.
A and B are both maintained in the population, the equilibrium frequencies are A = 0.6, B = 0.4
d.
A and B are both maintained in the population, the equilibrium frequencies A = 0.9, B = 0.1
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Q120
mcq
Antelopes are proposed to form groups to reduce the risk of predation. A researcher measured the predation of individuals in groups of different sizes. She found that per capita mortality risk decreased with increasing group size for males (solid line) but remained unchanged for females (dashed line). Furthermore, males in all groups experienced greater per capita mortality risk than females.
Identity the graph below that best depicts the above findings :
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q121
mcq
The prominent mammal species found in four different protected areas are listed below :
Area A : Tiger, Wild dog, Leopard, Elephant.
Area B : Common langur, Barking deer, Wild dog, Elephant.
Area C : Tiger, Indian rhinoceros, Pygmy hog, Wild pig.
Area D : Blackbuck, Indian gazelle, Hyena, Indian wolf.
The area with the greatest phylogenetic diversity is
a.
A
b.
B
c.
C
d.
D
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Q122
mcq
The Hardy-Weinberg principle states that allele frequencies in a population will remain constant over generations if certain assumptions are met.
A. Random mating.
B. Mate choice.
C. Small population size.
D. Large population size.
E. Lack of mutations.
F. Directional selection.
Which of the above factors will cause changes in allele frequencies over generations?
a.
A, D and F
b.
B, D and F
c.
A, C and E
d.
B, C and F
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Q123
mcq
Given below are few traits and related functions :
| Trait | Function |
| :--- | :--- |
| (i) Aposematism | A. Acquiring food |
| (ii) Basking | B. Avoiding predation |
| (iii) Cooperative hunting | C. Territory defence |
| (iv) Song | D. Thermoregulation |
Match the above given traits to their most likely functions.
a.
i - C, ii - D, iii - B, iv - A
b.
i - D, ii - B, iii - A, iv - C
c.
i - B, ii - D, iii - A, iv - C
d.
i - C, ii - A, iii - D, iv - B
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Q124
mcq
Following is a diagrammatic representation of human evolutionary tree.
In the above diagram A, B, C and D respectively represent :
a.
Denisovan, *Homo habilis*, *Homo erectus*, *Homo neanderthalensis*
b.
*Homo habilis*, *Homo erectus*, *Homo neanderthalensis*, Denisovan
c.
*Homo erectus*, *Homo habilis*, *Homo neanderthalensis*, Denisovan
d.
*Homo erectus*, Denisovan, *Homo neanderthalensis*, *Homo habilis*
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Q125
mcq
Given below are names of the animals in column X and the accessory respiratory organs in teleost fishes (column Y).
| Column X | Column Y |
| :--- | :--- |
| A. *Anabas* | (i) Labyrinthine organ |
| B. *Clarias* | (ii) Air sacs |
| C. *Amphipnous* | (iii) Supra branchial cavity |
| D. *Channa* | (iv) Arborescent organ |
The correct match of the animals with the accessory respiratory organs they have are :
a.
A - (iv), B - (iii), C - (ii), D - (i)
b.
A - (iii), B - (iv), C - (i), D - (ii)
c.
A - (i), B - (iv), C - (ii), D - (iii)
d.
A - (ii), B - (i), C - (iii), D - (iv)
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Q126
mcq
The terms expressing some of the developmental events or specific body structures are given in column X and the names of animals that are associated with them in column Y.
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{Column X} & \multicolumn{2}{c|}{Column Y} \\
\hline
A. & Torsion & (i) & Star fish \\
\hline
B. & Metaganesis & (ii) & \textit{Obelia} \\
\hline
C. & Apolysis & (iii) & \textit{Taenia} \\
\hline
D. & Pedicellaria & (iv) & Apple snail \\
\hline
\end{tabular}
The correct match of the terms in column X with the name of animals in column Y is :
a.
A - (i), B - (ii), C - (iii), D - (iv)
b.
A - (iv), B - (ii), C - (iii), D - (i)
c.
A - (iii), B - (i), C - (ii), D - (iv)
d.
A - (ii), B - (iv), C - (i), D - (iii)
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Q127
mcq
The table lists characteristic anatomical features and names of plants.
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{Anatomical features} & \multicolumn{2}{c|}{Plants} \\
\hline
(i) & Protostele, xylem core surrounded by phloem & A. & \textit{Lycopodium} \\
\hline
(ii) & Siphonostele, centre pith present or medulated protostele & B. & \textit{Marsilea rhizome} \\
\hline
(iii) & Eustele, conjoint vasculature on edges of the pith & C. & \textit{Selaginella species} \\
\hline
& & D. & \textit{Equisetum} \\
\hline
\end{tabular}
Choose the option that correctly matches plant with their characteristic features.
a.
i - C, ii - B, iii - D
b.
i - A, ii - C, iii - D
c.
i - C, ii - A, iii - B
d.
i - A, ii - B, iii - D
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Q128
mcq
The table given below provides a list of female gametophyte features and plant genera
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{Female Gametophyte} & \multicolumn{2}{c|}{Plant Genera} \\
\hline
(i) & Monosporic, 8 nucleate & A. & \textit{Allium} \\
\hline
(ii) & Monosporic, 4 nucleate & B. & \textit{Oenothera} \\
\hline
(iii) & Bisporic, 8 nucleate & C. & \textit{Peperomia} \\
\hline
(iv) & Tetrasporic, 16 nucleate & D. & \textit{Polygonum} \\
\hline
\end{tabular}
Which one of the following options correctly matches the plant genera to female gametophyte features ?
a.
i - D, ii - C, iii - A, iv - B
b.
i - D, ii - B, iii - A, iv - C
c.
i - A, ii - B, iii - D, iv - C
d.
i - D, ii - B, iii - C, iv - A
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Q129
mcq
Following are some generalizations related to wood anatomy of higher plants :
A. The axial system of conifer woods consist mainly or entirely of tracheids.
B. The rays of conifers typically contain only parenchyma cells.
C. The rays of angiosperms typically contain both sclerenchyma cells and tracheids.
D. Angiosperm wood may be either diffuse-porous or ring-porous.
Which one of the following options represents all correct statements ?
a.
A and B only
b.
A and D only
c.
B and C only
d.
C and D only
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Q130
mcq
A field ecologist gathers following data (abundance values) in order to study diversity of species in four plant communities.
Based on the above observations, the ecologist draws following conclusions :
A. Plant communities $\text{C}_1$ and $\text{C}_4$ show strong similarity with each other.
B. Plant communities $\text{C}_1$ and $\text{C}_4$ as well as communities $\text{C}_2$ and $\text{C}_3$ show strong similarity with each other.
C. Plant community $\text{C}_1$ is most diverse.
D. Plant community $\text{C}_4$ is most diverse.
Which of the following statements is correct regarding above conclusions ?
a.
All the conclusions are correct
b.
Only conclusions A and D are correct
c.
Only conclusions A and C are correct
d.
Only conclusions B and D are correct
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Q131
mcq
The table given below lists types of plant communities and types of growth forms.
Which of the following is the best match for the plant communities with most dominant growth form generally present in that community ?
a.
i - D, ii - A, iii - B, iv - C
b.
i - C, ii - A, iii - B, iv - D
c.
i - B, ii - C, iii - D, iv - C
d.
i - C, ii - A, iii - D, iv - C
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Q132
mcq
Following are some of the generalizations regarding energy flow in an ecosystem :
A. Assimilation efficiency of carnivores is higher than herbivores.
B. Consumption efficiency of aquatic herbivores is higher than terrestrial herbivores.
C. Vertebrates have higher production efficiencies than invertebrates.
D. Trophic-level transfer efficiency is higher in terrestrial food chains than in marine.
Based on the above, select the correct option.
a.
Only A and C
b.
Only A and B
c.
A, B and C
d.
A, C and D
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Q133
mcq
In an experiment to show that biogeochemical cycles interact, nitrogen fixing vines (\textit{Galactia} sp.) were grown in plots under normal levels of $\text{CO}_2$ (Control) and under artificially elevated atmospheric $\text{CO}_2$ (Experimental). Effect of elevated $\text{CO}_2$ levels on nitrogen fixation was measured over a period of 7 years (Plot A) and the concentrations of iron and molybdenum in the leaves of these plants were quantified at the end of the study (Plot B). Which one of the following inferences CANNOT be made from the above experiment ?
a.
Decreasing rate of N-fixation correlated with decreases levels of leaf iron and molybdenum, two micronutrients essential for N-fixation
b.
An initial exposure to elevated $\text{CO}_2$ increased N-fixation by these plants
c.
There is a continuous decrease in N-fixation due to elevated $\text{CO}_2$ treatment.
d.
Plants exposed to continuous elevated levels of $\text{CO}_2$ had lower levels of iron and molybdenum in their leaves
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Q134
mcq
Match the following invasive plants to the likely habitats in which they are expected to occur :
| | Invasive plant | | Habitat (s) that they invade |
|---|---|---|---|
| A. | *Eichhornia crassipes* | (i) | Arid and semi – arid habitats |
| B. | *Lantana camara* | (ii) | Dry and moist tropical forests |
| C. | *Prosopis juliflora* | (iii) | Wetlands |
a.
A - (ii), B - (i), C - (iii)
b.
A - (i), B - (iii), C - (ii)
c.
A - (iii), B - (ii), C - (i)
d.
A - (iii), B - (i), C - (ii)
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Q135
mcq
Incorporating additional ecological factors into the Lotka-Voltera predator-prey model can change the predator-prey model can change the predator isocline. Given below are three state-space graphs (A-C) representing modification of predator isocline due to the ecological factors listed below (i-iii)
(i) Victim abundance acting as predator carrying capacity.
(ii) Availability of alternate prey (victim) population.
(iii) Predator carrying capacity determined by factor other than victim abundance.
Which one of the following options represents all correct matches of state-space graphs with their ecological factor ?
a.
A - (ii), B - (iii), C - (i)
b.
A - (ii), B - (i), C - (iii)
c.
A - (iii), B - (ii), C - (i)
d.
A - (i), B - (ii), C - (iii)
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Q136
mcq
Following statements were given regarding factors influencing variation in expression levels of transgene in transgenic plants :
A. Difference in restriction enzyme sites within the T-DNA.
B. Difference in copy number of the transgene.
C. Variation in site of integration of the T-DNA within the plant genome.
D. Presence of multiple promoters within the T-DNA region.
Which one of the following options represents a combination of statements that would NOT lead to variations in transgene expression levels in transgenic plants generated using the same T-DNA binary vector ?
a.
A and C only
b.
B only
c.
C and D only
d.
A and D only
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Q137
mcq
The above figure show the fluorescence emission spectra of three different proteins. Protein (X), Protein (Y), and Protein (Z) excited at 280 nm.
Which one of the following statements gives the correct interpretation.
a.
Proteins (Y) and (Z) have tryptophan while protein (X) has only phenylalanine
b.
Proteins (X) has only tyrosine and protein (Y) has tryptophan on the surface while protein (Z) has tryptophan buried inside
c.
Protein (X) has tryptophan buried inside while proteins (Y) and (Z) have tryptophan on the surface
d.
Protein (X) has only tyrosine and protein (Y) has tryptophan buried and protein (Z) has tryptophan on the surface
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Q138
mcq
Specimens for light microscopy are commonly fixed with a solution containing chemicals that crosslink/ denature cellular constituents. Commonly used fixatives such as formaldehyde and methanol could act in various ways as described below :
A. Formaldehyde crosslinks amino groups on adjacent molecules and stabilizes protein-protein and protein-nucleic acid interactions.
B. Methanol acts as a denaturing fixative and acts by reducing the solubility of protein molecules by disrupting hydrophobic interactions.
C. Formaldehyde crosslinks lipid tails in biological membranes.
D. Methanol acts on nucleic acids, crosslinks nucleic acids with proteins and thus stabilizes protein-nucleic acid interactions.
Which one the following combinations represents all correct statements ?
a.
A and C
b.
B and C
c.
B and D
d.
A and B
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Q139
mcq
Rum off transcription assays were performed to establish the specificity of three novel sigma factors for their promoters. Results of the experiments are shown below :
Following inferences were made from these results :
A. $\sigma^A$ initiates transcription from $P_2$ and $\sigma^B$ from $P_1$.
B. $\sigma^C$ can initiate transcription from both promoters.
C. $\sigma^B$ prevents initiation of transcription from $P_2$.
D. $\sigma^A$ initiates transcription from $P_1$.
Choose the option that correctly intersects the results.
a.
A, B and C only
b.
A and B only
c.
C and D only
d.
B, C and D only
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Q140
mcq
Based upon phenotypic observation, it was concluded that an unknown gene responsible for an agronomically important trait is present in a particular plant. In order to identify the gene, a researcher propose to use the following strategies :
A. PCR amplification of the gene.
B. Map based cloning of the gene.
C. Subtractive DNA hybridization.
D. Genome sequencing.
E. Develop molecular markers linked to the trait.
Which one of the following options is most suitable for identifying the unknown gene ?
a.
A and C
b.
B and E
c.
C only
d.
A and D
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Q141
mcq
A $\text{T}_0$ transgenic plant contains two unlinked copies of the T-DNA of which, one is functional and the other is silenced. Segregation of the transgenic to non-transgenic phenotype would occur in a ....(i).... ratio in progeny obtained by backcrossing and in a ....(ii).... ratio in F1 progeny obtained by self-pollination.
Fill in the blanks with the correct combination of (i) and (ii) from the options given below:
a.
(i) - 3 : 1 and (ii) - 15 : 1
b.
(i) - 1 : 1 and (ii) - 3 : 1
c.
(i) - 3 : 1 and (ii) - 3 : 1
d.
(i) - 1 : 1 and (ii) - 15 : 1
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Q142
mcq
Column X lists two diseases and column Y lists name of proteins which are commonly used for routine clinical diagnosis of these diseases
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{Column X} & \multicolumn{2}{c|}{Column Y} \\
\hline
A. & Myocardial Infarction & (i) & Amylase \\
\hline
B. & Pancreatitis & (ii) & Creatine kinase \\
\hline
& & (iii) & Lipase \\
\hline
& & (iv) & Troponin \\
\hline
\end{tabular}
Find out the correct combination
a.
A - (ii), B - (i) ; A - (iv), B - (iii)
b.
A - (iii), B - (iv) ; A - (ii), B - (i)
c.
A - (i), B - (ii) ; A - (iii), B - (iv)
d.
A - (iv), B - (iii) ; A - (i), B - (ii)
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Q143
mcq
Given blow are the steps to assess the population size of grasshoppers in a given area:
A. 'n' individuals are collected randomly from the study area in a defined period of time.
B. The captured individuals are counted marked and released at the site of collection. Next day, individuals are captured from the same site for same length of time. Number of marked ($n_m$) and unmarked ($n_u$) individuals are separated and counted.
A. 'n' individuals are collected randomly from the study area in a defined period of time.
B. The captured individuals are counted marked and released at the site of collection. Next day, individuals are captured from the same site for same length of time. Number of marked ($n_m$) and unmarked ($n_u$) individuals are separated and counted.
C. This capture-release and recapture is continued till one gets 100% marked individuals.
D. The size of the population (N) is estimated as follows :
$$\frac{N}{n} = \frac{m_m + n_u}{n_m}$$
E. The size of population (N) is estimated as follows :
$$\frac{N}{n} = \frac{n_u}{n_m}$$
The most appropriate combination of steps for estimating population size using mark-recapture method is :
a.
A, B and D
b.
A, B and E
c.
A, B, C and D
d.
A, B, C and E
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Q144
mcq
A neurophysiologist was interested in using the patch-clamp technique. Following statements are related to this technique :
A. Intracellular movement of ion channels.
B. Post-translational modification of the ion channel protein.
C. Ligand that controls the opening or closing of ion channels.
D. Change in current flow in a single ion channel.
Which one the following combinations will be achievable using the patch-clamp technique ?
a.
A and B
b.
B and C
c.
C and D
d.
D and A
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Q145
mcq
The blood plasma proteins (albumin and globulins) from a healthy person were separated by electrophoresis as shown above. The diagnosis of acute inflammation can be done based on one of the following observations :
a.
Increase in both $\alpha 1$ and $\alpha 2$, decrease in albumin.
b.
Increase in albumin, decrease in $\alpha 1$, $\alpha 2$ and $\beta$
c.
Increase in albumin and decrease in $\gamma$-globulin
d.
Only decrease in albumin
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