CSIR NET · Life Sciences
December
2017
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121 questions
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Q21
mcq
Choose the correct statement from the following:
a.
Disulfide bonds in a 20-residue peptide can be formed only if the cysteines are adjacent to each other.
b.
The amino acid isoleucine has only one chiral centre.
c.
Both bases and sugar contribute to chirality of nucleic acids.
d.
The pI of aspartic acid is less than that of glutamic acid.
Correct Answer
Step-by-Step AI Explanation
Verified Method
Statement D is correct: The $\text{p}K_a$ values for aspartic acid are $\text{p}K_1 \approx 1.88$, $\text{p}K_2 \approx 9.60$, $\text{p}K_R \approx 3.65$, giving a $\text{pI} = \frac{1.88 + 3.65}{2} = 2.77$. For glutamic acid, $\text{p}K_1 \approx 2.19$, $\text{p}K_2 \approx 9.67$, $\text{p}K_R \approx 4.25$, giving a $\text{pI} = \frac{2.19 + 4.25}{2} = 3.22$. Therefore, the $\text{pI}$ of aspartic acid is less than that of glutamic acid.
- Statement A is incorrect because cysteines do not need to be adjacent; in fact, adjacent cysteines rarely form intramolecular disulfide bonds due to conformational strain.
- Statement B is incorrect because isoleucine has two chiral centers ($C_\alpha$ and $C_\beta$).
- Statement C is incorrect because nitrogenous bases are planar and achiral; only the sugar moiety contributes to chirality in nucleic acids.
Q22
mcq
Indicate the INCORRECT statement from the following:
a.
Allosteric enzymes function through reversible noncovalent binding of allosteric modulators or effectors.
b.
Monoclonal antibodies that catalyze hydrolysis of esters or carbonates can be produced.
c.
Enzymes are not inhibited irreversibly by heavy metals such as $\text{Hg}^{2+}$, $\text{Ag}^+$.
Correct Answer
d.
Acid phosphatases hydrolyze biological phosphate esters at $\sim \text{pH } 5.0$.
Step-by-Step AI Explanation
Verified Method
Statement C is the INCORRECT statement (making it the correct choice): Heavy metal ions such as $\text{Hg}^{2+}$, $\text{Pb}^{2+}$, and $\text{Ag}^{+}$ bind tightly to sulfhydryl groups ($-\text{SH}$) of cysteine residues in enzymes, often acting as potent irreversible inhibitors.
- Statement A is correct because allosteric enzymes are regulated via noncovalent, reversible binding of effectors.
- Statement B is correct because catalytic antibodies (abzymes) can be raised against transition-state analogs to catalyze ester or carbonate hydrolysis.
- Statement D is correct because acid phosphatases exhibit optimal catalytic activity at an acidic pH around 5.0.
Q23
mcq
What is the effect of sudden increase in the levels of ATP and citrate on an erythrocyte undergoing glycolysis?
a.
It inhibits glycolysis.
Correct Answer
b.
It stimulates glycolysis.
c.
The rate of glycolysis remains unaltered.
d.
The rate of glycolysis increases gradually.
Step-by-Step AI Explanation
Verified Method
Phosphofructokinase-1 (PFK-1) is the primary rate-limiting enzyme of glycolysis. High concentrations of ATP act as an allosteric inhibitor of PFK-1 by lowering its affinity for fructose 6-phosphate. In addition, citrate is also a classic allosteric inhibitor of PFK-1 that enhances the inhibitory effect of ATP. Although mature erythrocytes lack mitochondria (and thus do not produce citrate endogenously), an increase in levels of ATP and citrate directly inhibits PFK-1, thereby inhibiting glycolysis.
Q24
mcq
The $\phi$ and $\psi$ values of a $\beta$-strand composed of all D-amino acids will mainly occupy which quadrant in the Ramachandran plot?
a.
upper left
b.
upper right
c.
lower left
d.
lower right
Correct Answer
Step-by-Step AI Explanation
Verified Method
In a standard Ramachandran plot for L-amino acids, $\beta$-strands are located in the upper-left quadrant (negative $\phi$, positive $\psi$, typically around $\phi \approx -120^\circ$ to $-140^\circ$, $\psi \approx +120^\circ$ to $+140^\circ$). Because D-amino acids have inverted stereochemistry, their Ramachandran plot is centrosymmetric (inverted through the origin, i.e., $(\phi, \psi) \to (-\phi, -\psi)$) relative to that of L-amino acids. Thus, the corresponding region for a $\beta$-strand composed of D-amino acids has positive $\phi$ and negative $\psi$, which lies in the lower-right quadrant.
Q25
mcq
In a signalling event, binding of an extracellular ligand activates G-protein coupled receptor (GPCR) that eventually activates phospholipase $\text{C}-\beta$. Which one of the following statements truly reflects the function of phospholipase $\text{C}-\beta$?
a.
Phospholipase $\text{C}-\beta$ converts $\text{PI }(3, 4, 5)\text{P}_3$ to $\text{PI }(4,5)\text{P}_2$
b.
Phospholipase $\text{C}-\beta$ converts $\text{PI}(4)\text{P}$ to $\text{PI }(4,5)\text{P}_2$
c.
Phospholipase $\text{C}-\beta$ converts $\text{PI }(4,5)\text{P}_2$ to diacylglycerol and $\text{IP}_3$
Correct Answer
d.
Phospholipase $\text{C}-\beta$ converts $\text{PI }(5)\text{P}$ to $\text{PI }(4,5)\text{P}_2$
Step-by-Step AI Explanation
Verified Method
Phospholipase $\text{C}-\beta$ ($\text{PLC}-\beta$) is activated downstream of GPCRs via the $\text{G}_{\alpha q/11}$ or $\text{G}_{\beta\gamma}$ subunits. It hydrolyzes phosphatidylinositol 4,5-bisphosphate [$\text{PI}(4,5)\text{P}_2$] into two important second messengers: inositol 1,4,5-trisphosphate ($\text{IP}_3$) and diacylglycerol (DAG).
Q26
mcq
Select a cellular body which is NOT a part of the nuclear bodies:
a.
P-bodies
Correct Answer
b.
Nucleolus
c.
Cajal bodies
d.
Interchromatin granule clusters
Step-by-Step AI Explanation
Verified Method
P-bodies (processing bodies) are cytoplasmic ribonucleoprotein (RNP) granules involved in mRNA degradation, translational repression, and mRNA storage. They are located in the cytoplasm, not inside the nucleus. In contrast, the nucleolus, Cajal bodies, and interchromatin granule clusters (nuclear speckles) are well-known nuclear bodies.
Q27
mcq
Which one of the following statements about chromatin is NOT true?
a.
DNA winds approximately 1.65 times around the nucleosomes
b.
H2A-H2B bind to both the entry and exit ends of DNA in nucleosomes
Correct Answer
c.
Covalent modification of histones influence chromatin compaction
d.
Non-histone proteins are part of mitotic chromosomes
Step-by-Step AI Explanation
Verified Method
Statement B is NOT true: The histone octamer consists of a central $(\text{H3-H4})_2$ tetramer flanked by two $\text{H2A-H2B}$ dimers. The $(\text{H3-H4})_2$ tetramer organizes the central region and binds DNA near the entry and exit sites, specifically the N-terminal tails and core regions of H3 organize DNA at the entry and exit of the nucleosome core particle. Therefore, stating that H2A-H2B bind to both the entry and exit ends of DNA is incorrect.
- Statement A is correct: DNA wraps around the histone core approximately 1.65–1.67 times (about 146–147 bp).
- Statement C is correct: Histone modifications like acetylation, methylation, and phosphorylation directly dictate chromatin folding and compaction.
- Statement D is correct: Mitotic chromosomes contain substantial amounts of non-histone proteins, including condensins, topoisomerase II, and cohesins.
Q28
mcq
During eukaryotic cell division, metaphase to anaphase transition is regulated by degradation of
a.
Cyclin B1
Correct Answer
b.
CDK1
c.
Aurora A kinase
d.
Polo-like kinase
Step-by-Step AI Explanation
Verified Method
The metaphase-to-anaphase transition is triggered by the Anaphase-Promoting Complex/Cyclosome (APC/C) activated by Cdc20. The $\text{APC/C}^{\text{Cdc20}}$ targets two key proteins for ubiquitin-mediated proteasomal degradation: securin (releasing separase to cleave cohesin) and Cyclin B1 (inactivating CDK1 to allow exit from mitosis).
Q29
mcq
One of the mechanisms used by bacteria for adaptation to changed environment is altering transcription of their genes. In this regard, which one of the following responses is NOT found in bacteria?
a.
A gene with two different promoters for expression in different conditions
b.
Use of different sigma factors for transcription of genes
c.
Expression of alternate $\alpha, \beta$ and $\beta '$ subunits
Correct Answer
d.
Expression of anti-sigma factors
Step-by-Step AI Explanation
Verified Method
In bacteria, core RNA polymerase subunits ($\alpha_2\beta\beta'\omega$) are conserved and not typically replaced by alternative forms to respond to environmental changes. Instead, bacteria alter transcription through different sigma factors, anti-sigma factors, and alternative promoters recognized under different conditions.
Q30
mcq
Which one of the following $\lambda$ proteins acts both as an activator and repressor of transcription?
a.
cI protein
Correct Answer
b.
N protein
c.
cII protein
d.
Q protein
Step-by-Step AI Explanation
Verified Method
The $\lambda$ cI repressor protein acts as both a repressor and an activator. At low concentrations, it binds to $O_{R}1$ and $O_{R}2$, repressing the $P_R$ promoter (preventing lytic gene expression) while activating transcription from $P_{RM}$ (stimulating its own synthesis). At high concentrations, it binds to $O_{R}3$, repressing $P_{RM}$ as well.
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Q31
mcq
A highly specific inhibitor that targets the phosphorylation activity of TFIIH is added to an in vitro transcription reaction. Which one of the following steps is most likely to be affected?
a.
Binding of RNA polymerase to promoter sequence
b.
Promoter clearance
c.
Recruitment of TFIID
d.
Open promoter complex formation
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Q32
mcq
During eukaryotic protein synthesis, stress conditions result in activation of specific kinases leading to phosphorylation of a key translation initiation factor that inhibits protein synthesis from a large number of cellular mRNA. Which one of the following factors is the target of the kinase?
a.
eIF4E
b.
eIF4G
c.
eIF2$\alpha$
d.
Gcn4
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Q33
mcq
Proteins with cytoplasmic domains having tyrosine kinase activity do NOT act as receptors for
a.
Epidermal growth factor (EGF)
b.
Platelet-derived growth factor (PDGF)
c.
Insulin
d.
Transferrin
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Q34
mcq
Which one of the following is a group of signalling molecules that act as morphogens during development of an organism and its effects are mediated through the receptor Patched and its binding partner Smoothened?
a.
Hedgehog protein
b.
Notch protein
c.
Wnt protein
d.
$\beta$-catenin
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Q35
mcq
Junctions which tether cytoskeletal filaments inside the cell are known as
a.
anchoring junctions
b.
occluding junctions
c.
channel – forming junctions
d.
signal – relaying junctions
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Q36
mcq
Which one of the following human serum immunoglobulins takes part in classical complement fixation pathway?
a.
IgD
b.
IgE
c.
IgA
d.
IgG
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Q37
mcq
Match the following cleavage patterns with the species in which they occur.
\begin{tabular}{|l|l|l|l|}
\hline
& Species & & Cleavage Pattern \\
\hline
A. & Flatworm & i. & Meroblastic discoidal \\
\hline
B. & Frog & ii. & Meroblastic superficial \\
\hline
C. & Birds & iii. & Holoblastic displaced radial \\
\hline
D. & Insect & iv. & Holoblastic spiral \\
\hline
\end{tabular}
a.
A – iv, B – iii, C – i, D – ii
b.
A – iii, B – i, C – iv, D – ii
c.
A – ii, B – iii, C – i, D – iv
d.
A – ii, B – iv, C – iii, D – i
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Q38
mcq
Which one of the following statements regarding limb development in mice is true?
a.
The gene encoding Tbx5 is transcribed in the limb fields of the hindlimbs.
b.
The gene encoding Tbx4 is transcribed in the limb fields of the forelimbs.
c.
Genes encoding Islet 1, Tbx4 and Pitx are expressed in the presumptive hindlimb.
d.
Genes encoding Islet 1, Tbx4 and Pitx are expressed in the presumptive forelimb
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Q39
mcq
Based on ABC model during flower development, loss of class A activity results in the formation of only stamen and carpel. Which of the following floral organ identity genes controls the class A activity?
a.
\textit{APETALA 1} and \textit{APETALA 2}
b.
\textit{APETALA 3} and \textit{PISTILLATA}
c.
Only \textit{PISTILLATA}
d.
Only \textit{AGAMOUS}
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Q40
mcq
In a given experiment, transplantation of micromeres from the vegetal pole of a 16-cell sea urchin embryo onto the animal pole of a host 16-cell sea urchin embryo would initiate :
a.
the transplanted muicromeres to invaginate into the blastocoel to create a new set of skeletogenic mesenchyme cells
b.
the transplanted micromeres to ingress into the blastocoel to create a new set of skeletogenic mesenchymal cells
c.
the transplanted micromeres will mingle with the host micromeres to ingress into the blastocoel to create skeletogenic mesenchyme cells.
d.
the transplanted micromeres will form the secondary archenteron.
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Q41
mcq
Which one of the following is NOT a phenotype of dark-grown seedlings that are etiolated?
a.
Short hypocotyls
b.
An apical hook
c.
Closed cotyledons
d.
Non-photosynthetic proplastids
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Q42
mcq
Which one of the following is the correct function of JAZ (JASMONATE ZIM-DOMAIN) protein family, a key regulator of Jasmonic Acid (JA) signalling response?
a.
Binds to MYC2 and represses the JA dependent genes.
b.
Binds to MYC2 and transcribes JA dependent genes.
c.
Acts as receptor of JA signal.
d.
Involved in directly inducing JA dependent genes.
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Q43
mcq
The plant hormone, Gibberellic Acid is generally NOT associated with
a.
stem elongation
b.
parthenocarpy
c.
parthenogenesis
d.
malt production
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Q44
mcq
Which one of the following statements is NOT correct for Casparian strip?
a.
It breaks the continuity of water movement through the apoplast pathway
b.
It is formed in the growing part of the root
c.
It is formed several millimetres or several centimetres behind the root tip
d.
It is a band within the radial cell walls of the endodermis that is impregnated with lignin
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Q45
mcq
Which one of the following is NOT involved with the absorption of iron in the intestine?
a.
Divalent metal transporter
b.
Ferroportin 1
c.
Hephaestin
d.
Transferrin
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Q46
mcq
In which one of the body fluids is $\text{K}^+$ concentration higher than that of $\text{Na}^+$?
a.
Plasma
b.
Perilymph
c.
Endolymph
d.
Cerebrospinal fluid
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Q47
mcq
Mammillary bodies are present in
a.
thalamus
b.
epithalamus
c.
hypothalamus
d.
midbrain
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Q48
mcq
Reflex ovulation does NOT occur in
a.
cats
b.
rabbits
c.
mink
d.
rats
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Q49
mcq
Two mutant plants, both bearing white flowers, were crossed. All $\text{F}_1$ plants had red coloured flowers. When an $\text{F}_1$ plant was selfed it produced progeny with either red or white coloured flowers in $9 : 7$ ratio. Based on this information, which one of the following conclusions is correct?
a.
The mutations in the parents do not complement each other
b.
The mutations in the parents are allelic
c.
The mutations in the parents are non-allelic
d.
The mutations in the parents are linked
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Q50
mcq
In a linkage map, two genes A and B, are 70 cM apart. If individuals heterozygous for both the genes are test crossed number of progeny with parental phenotype will be:
a.
equal to the number of progeny with recombinant phenotype
b.
more than the number of progeny with recombinant phenotype
c.
less than the number of progeny with recombinant phenotype
d.
could be more or less than the number of progeny with recombinant phenotype depending on whether the genes are linked in *cis* or *trans*, respectively
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Q51
mcq
A researcher exposed *Drosophila* larvae to $37^\circ\text{C}$ during their growth. One of the adult flies that emerged had a crossveinless phenotype. Crossveinless is a known mutant in *Drosophila*. When this crossveinless fly was crossed to a known crossveinless mutant fly all the progeny had normal phenotype. The observed phenotype can be best explained as an example of
a.
Conditional mutant
b.
Phenocopy
c.
Penetrance
d.
Pleiotropy
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Q52
mcq
Phages are collected from an infected *E. coli* donor strain of genotype $cys^+ leu^+ thr^+$ and used to transduce a recipient of genotype $cys^- leu^- thr^-$. The treated recipient population is plated on a minimal medium supplemented with leucine and threonine. Many colonies grew. Which one of the following combination of genotypes are appropriate for the colonies that grew?
a.
$cys^+ leu^+ thr^+$, $cys^+ leu^- thr^+$, $cys^- leu^+ thr^-$
b.
$cys^- leu^+ thr^+$, $cys^+ leu^- thr^-$, $cys^+ leu^+ thr^-$
c.
$cys^- leu^- thr^-$, $cys^- leu^- thr^+$, $cys^- leu^+ thr^-$
d.
$cys^+ leu^- thr^-$, $cys^+ leu^- thr^+$, $cys^+ leu^+ thr^-$
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Q53
mcq
Given below are growth equations where $dN/dt$ is defined as
A. $rN/K$
B. $rN$
C. $rN[(K-N)/N]$
D. $rN[(K-N)/K]$
With reference to the above equations, which one of the following statements is correct?
a.
B represents exponential growth and A represents logistic growth
b.
B represents exponential growth and D represents logistic growth
c.
B represents zero growth and C represents logistic growth
d.
A represents exponential growth and D represents logistic growth
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Q54
mcq
Among the following statements, which is the correct one that refers to a Holotype?
a.
Specimens collected from different locations and designated as type specimens by the author
b.
A single specimen or illustration upon which name is based and designated as nomenclature type by the author
c.
Specimens collected from different places and designated as type specimen
d.
A single specimen designated to serve as nomenclatural type when all of the materials on which the name of the taxon was based is missing
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Q55
mcq
Which one of the following statements is true about xylem in plants?
a.
It is characterized by the presence of tracheary elements responsible for the conduction of water in vascular plants
b.
It is responsible for the transport of water and characterized by sieve elements like parenchyma cells and sclereids
c.
It is responsible for the transport of assimilates in the vascular plants and characterized by tracheary elements.
d.
It is responsible for the transport of assimilates in both vascular and non-vascular plants
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Q56
mcq
Identify the plant species from which artemisinin, an anti-malarial drug, is extracted.
a.
*Artemisia maritima*
b.
*Artemisia scoparia*
c.
*Artemisia annua*
d.
*Cinchona officinalis*
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Q57
mcq
Which of the following statements is IN-CORRECT about a keystone species?
a.
Species other than consumers can be a keystone species
b.
Keystone species has influence on a community proportionate to its abundance
c.
Removing a keystone species can reduce species richness of a community
d.
Removing a keystone species can effect successive trophic levels causing a trophic cascade
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Q58
mcq
A species whose life history strategies allow for high intrinsic rates of increase (r-strategist) will also exhibit the following EXCEPT
a.
high tolerance for both environmental instability and low quality resources.
b.
short period of exponential population growth (r)
c.
reproductive strategy that involves random mating, semelparity and little or no parental investment
d.
survivorship that show density-dependent mortality, typically exhibiting Type 1 or 2 survivorship curves.
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Q59
mcq
In the context of diversity patterns of species, which one of the following statements is INCORRECT?
a.
Alpha diversity is diversity within a single community
b.
Beta diversity is a measure of the change in species composition from one community or habitat to another
c.
Alpha diversity is the regional diversity found among range of communities in a geographical region
d.
Gamma diversity is the regional diversity found among range of communities/habitats in a geographical region
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Q60
mcq
Given below is an ecological pyramid.
The above pyramid represents:
a.
Pyramid of number of a parasitic food chain and pyramid of biomass of a pond ecosystem
b.
Pyramid of number of a pond ecosystem and pyramid of biomass of a forest ecosystem
c.
Pyramid of energy of a grassland and pyramid of biomass of an open ocean ecosystem
d.
Pyramid of biomass of a grassland and pyramid of number of a tropical forest ecosystem
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Q61
mcq
Which one of the following statements is NOT TRUE about the Neutral Theory as proposed by Motoo Kimura?
a.
Except for advantageous mutations, most alleles are under neutral selection
b.
The rate of evolution for most genes will be equal to the neutral mutation rate
c.
Advantageous mutations are exceedingly rare
d.
At the level of DNA sequences, genetic drift dominates evolution
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Q62
mcq
Which one of the following statements is NOT TRUE about homologous characters?
a.
Similar traits may not be homologous
b.
Similar traits may be a result of convergent evolution
c.
A homologous trait that is derived and shared from a common ancestor is called an autapomorphy
d.
Homologous characters may show structural similarity but functional diversity
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Q63
mcq
Which one of the following trees represents a fully resolved phylogram?
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q64
mcq
The rank/abundance plot given below illustrates three well known species abundance curves (a, b, c).
Based on the shapes of the curves select the correct option.
a.
a-exponential, b-log normal, c-geometric series
b.
a-broken stick, b-geometric series, c-log normal
c.
a-broken stick, b-log normal, c-geometric series
d.
a-exponential, b-geometric series, c-log normal
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Q65
mcq
Which one of the following microscopes would you use to visualize a protein fused to an appropriate reporter in a living cell?
a.
Fluorescence microscope
b.
Scanning electron microscope
c.
Differential interference contrast microscope
d.
Phase contrast microscope
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Q66
mcq
Which one of the following statements regarding use of hybrid nucleases for plant genome engineering is INCORRECT?
a.
For gene knock out experiments, the nuclease is expressed without a donor DNA template.
b.
Hybrid nucleases typically comprise two protein subunits that dimerize at their nuclease domain.
c.
Zinc finger nucleases (ZFNs) can efficiently target all nuclear genes with equal efficiency.
d.
Both ZFNs and TALENs are fused with cleavage domains of FokI endonuclease.
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Q67
mcq
Which one of the following statements regarding proteins is CORRECT?
a.
$n \rightarrow \sigma^*$ transition requires less energy than $n \rightarrow \pi^*$ transition and can be monitored by mass spectrometry.
b.
$n \rightarrow \sigma^*$ transition requires more energy than $\pi \rightarrow \pi^*$ transition and can be monitored by UV-Vis spectroscopy.
c.
$\pi \rightarrow \pi^*$ transition requires less energy than $n \rightarrow \sigma^*$ transition and can be monitored by CD spectroscopy.
d.
$\sigma \rightarrow \sigma^*$ transition requires less energy than $n \rightarrow \pi^*$ transition and can be monitored by CD spectroscopy
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Q68
mcq
Which of the following host system is best suited to express large amounts of glycosylated protein for structural studies ?
a.
GST fusion protein in *E. coli*
b.
His-tagged protein in E.coli
c.
Native protein baculovirus
d.
Native protein in Pseudomonas
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Q69
mcq
Which of the following statements about YACs is FALSE?
a.
YACs can carry DNA fragments of 1Mb
b.
A single yeast may contain more than one YAC
c.
Rearrangements in YACs are rare because recombination is poor in yeast
d.
YACs have to be transferred to bacteria for subsequent DNA manipulations
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Q70
mcq
In an intact cell patch-clamp experiment,
a.
two electrodes are inserted into the cytosol but at different depths.
b.
one electrode is applied to the plasma membrane in a region containing only lipids and one into the cytosol.
c.
two electrodes are applied to the plasma membrane, one in a region containing only lipids and the other in a region containing one or few ion channels.
d.
one electrode is applied to the plasma membrane containing one or few ion channels and one electrode inserted into the cytosol.
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Q71
mcq
Match the coenzymes in column I serving as transient carriers of specific atoms or functional groups in column II
| | Column I | | Column II |
|---|---|---|---|
| A. | Coenzyme A | (i) | Aldehyde groups |
| B. | Flavin adenine dinucleotide | (ii) | Amino groups |
| C. | Pyridoxal phosphate | (iii) | Hydrogen atoms |
| D. | Thiamine pyrophosphate | (iv) | Acyl groups |
Select correct combinations from the options given below:
a.
A-(iv), B-(iii), C-(ii), D-(i)
b.
A-(iii), B-(iv), C-(i), D-(ii)
c.
A-(i), B-(ii), C-(iii), D-(iv)
d.
A-(ii), B-(i), C-(iv), D-(iii)
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Q72
mcq
Out of the statements mentioned below
A. L-threonine and L-$allo$-threonine interact identically with plane polarized light.
B. van der Waals' interactions are always attractive.
C. Poly (pro) II-helix is not stabilized by intermolecular hydrogen bonds.
D. The folding of a protein is associated with an overall positive change in free energy and negative change in entropy.
E. Lysine acetylation on histone is associated with loosening of the histone complex from DNA.
Which of the following combinations is CORRECT?
a.
A and C
b.
B and D
c.
C and E
d.
D and E
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Q73
mcq
The following statements are made:
A. $\alpha$ and $\beta$ anomers of glucose are inter-convertible and the ratio of their abundance is $1 : 2$, respectively.
B. Single chain lipids ($\ge\text{C}_{14}$) form micelles and double chain lipids form bilayers in water.
C. Proline is energetically favoured at the C-termini of an $\alpha$-helix than at the N-termini.
D. Major groove of DNA readily accommodates several common structural motifs in protein than the minor groove.
E. Replacement of a canonical Watson-Crick pairing by Wobble base pairs does not change the surface properties in t-RNA.
Which one of the following combinations is INCORRECT?
a.
A and D
b.
B and E
c.
C and E
d.
B and C
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Q74
mcq
From the following statements
A. Enzymes enhance reaction rates by a factor of 2 to 10.
B. The activation energy for a reaction is lowered by enzymes.
C. The interactions between enzymes and substrates are hydrogen bonding, hydrophobic and ionic.
D. Substrate concentration does not affect the rate of enzyme catalyzed reactions.
Pick the combination with all INCORRECT statements.
a.
A, B
b.
B, C
c.
A, C
d.
A, D
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Q75
mcq
Match the chemical agents that interfere in oxidative phosphorylation process with their respective mode of action.
| Column I | Column II |
| :--- | :--- |
| A. Antimycin A | (i) Inhibits $\text{F}_0$ component of ATP synthase |
| B. Oligomycin | (ii) Disrupts inner mitochondrial membrane potential |
| C. Valinomycin | (iii) Prevent electron transport from Fe/S cluster to ubiquinone |
| D. Rotenone | (iv) Blocks electron transfer from cytochrome b to cytochrome $\text{c}_1$ |
| | (v) Inhibits adenine nucleotide translocase |
Choose the correct combination from below:
a.
A - (ii), B - (iv), C - (v), D - (iii)
b.
A - (iv), B - (i), C - (ii), D - (iii)
c.
A - (i), B - (iii), C - (ii), D - (v)
d.
A - (v), B - (ii), C - (i), D - (ii)
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Q76
mcq
A polymer is synthesized from an achiral amino acid. Conformation of the polymer can be investigated by the following techniques.
A. Fibre diffraction
B. Nuclear magnetic resonance spectroscopy
C. Circular dichroism spectroscopy
D. Differential scanning calorimetry
Choose the combination which would indicate that the polymer adopts a helical conformation
a.
A, C
b.
B, D
c.
A, B
d.
C, D
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Q77
mcq
Sphingolipids (S) and cholesterol (C) molecules of the lipid bilayer aggregate into multiple tiny rafts instead of a single large one. Considering that size of a lipid raft depends on the affinity of S and C for one another and other lipids in the membrane, choose the option that best describes this property.
a.
S and C bind to one another tightly and independent of any other lipid molecules.
b.
S and C bind to one another with same affinity as they bind to other lipid species of the membrane.
c.
S and C bind to one another with high affinity under the influence of some cytoskeletal elements.
d.
S and C have slightly higher affinity than other lipid molecules of the membrane and are in dynamic equilibrium with their free forms.
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Q78
mcq
To understand the microtubule-dependent motor activity of a freshly purified motor protein from budding yeast, a researcher set up microtubule based gliding assay. In such an assay where microtubules are fluorescently tagged at its (+) end, the researcher observed that this motor protein moves the mircotubule in the direction of its (+) end as shown bleow:
The newly identified motor protein is
a.
Dynein
b.
Myosin
c.
Kinesin-1
d.
Either Dynein or Kinesin 1
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Q79
mcq
Given below are organelles (Column A) and properties associated with the organelles (column B).
$$\begin{array}{ll}
\textbf{Column A} & \textbf{Column II} \\
\text{(A) Lysosomes} & \text{(i) Anterograde transport from ER to Golgi} \\
\text{(B) } cis\text{–Golgi} & \text{(ii) Clathrin – coated vesicles} \\
\text{(C) } trans\text{–Golgi} & \text{(iii) Cop I vesicle budding} \\
\text{(D) Cop II vesicles} & \text{(iv) Mannose-6 phosphate receptor} \\
\text{(E) Endocytic vesicles} & \text{(v) Protein aggregate for secretion}
\end{array}$$
Choose the option that matches the organelles with the most appropriate property.
a.
A – (iv); B-(iii); C – (v); D – (i); E–(ii)
b.
A – (v); B-(iv); C – (i); D – (v); E–(ii)
c.
A – (iii); B-(v); C – (i); D – (iv); E–(ii)
d.
A – (iv); B-(v); C – (ii); D – (i); E–(iii)
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Q80
mcq
Cell cycle checkpoints are surveillance mechanisms that ensure order and fidelity of events of the cell cycle. Given below are some of the checkpoint proteins and their functions.
$$\begin{array}{ll}
\text{(A) Mad2} & \text{(i) Prevention of Cdc 14 activation} \\
\text{(B) Tem1} & \text{(ii) Prevention of Cdc20 activation} \\
\text{(C) ATM, ATR} & \text{(iii) Inhibition p21}^{\text{CIP}} \\
& \text{(iv) Inhibition of separase action}
\end{array}$$
Match the checkpoint protein with its function.
a.
A – (iv); B-(i) and (ii); C – (iii)
b.
A – (ii) and (iv); B-(i); C – (iii)
c.
A – (ii); B-(i) and (iii); C – (iv)
d.
A – (ii) and (iv); B-(iii); C – (i)
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Q81
mcq
You have discovered a new transposon, TnX, and would like to identify its mode of replication. A heteroduplex of the TnX sequence is made with a few mismatches and introduced into bacteria. The newly transposed genomic loci are sequenced. You find that the sequence of the transposon matched exactly with one of its parent strands. This suggests that
a.
TnX transposes by conservative transposition mechanism.
b.
TnX transposes using a site-specific recombination mechanism.
c.
single-strands of the duplex are inserted.
d.
TnX transposes by replicative mechanism.
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Q82
mcq
To assess the impact of a newly identified drug when added to a culture of subconfluent HeLa cells, a researcher analyzes the fluorescence activated cell sorting (FACS) profile of untreated ($-$Drug) versus treated ($+$ Drug) cells.
Based on the FACS profile shown above, this drug inhibits.
a.
$\text{G}_1$ phase of the cell cycle
b.
$\text{S}$ phase of the cell cycle
c.
$\text{G}_2/\text{M}$ phase of the cell cycle
d.
$\text{G}_0$ phase of cell cycle
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Q83
mcq
Following table lists the two major forms of DNA duplexes, conformation of base attached to the sugar and the nature of major and minor grooves.
Which of the following combination correctly depicts the types of DNA duplexes and their properties (numbered within bracket)?
a.
A - (i) (iii) (vi); B - (ii) (iii) (vi)
b.
A - (i) (iii) (vi); B - (ii) (iii) (v)
c.
A - (ii) (iv) (v); B - (ii) (iii) (vi)
d.
A - (ii) (iv) (v); B - (i) (iii) (vi)
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Q84
mcq
Imagine the following RNA sequence is translated in the mammalian cytosol and mitochondria.
RNA sequence:
AUG AUA CUG UGA CUU AGG CUC UAA
Following are some sequences putative peptide
Find out the correct combination of peptides made in the cytosol and mitochondria.
a.
(a) (i)
b.
(a) (ii)
c.
(b) (i)
d.
(b) (ii)
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Q85
mcq
In all organisms, it is critical that replication initiation be tightly controlled to ensure that chromosome number and cell number remain appropriately balanced. Given below are several statements regarding regulation of replication in *E. coli*.
A. Hemimethylation and sequestration of oriC (origin of replication) by a protein called SeqA prevents initiation of replication.
B. Availability of DnaA protein is an important requirement for initiation of replication.
C. The ratio of $\text{ADP} : \text{ATP}$ is important as high level of $\text{ADP}$ is required for initiation of replication.
D. Recruitment of Hda protein by sliding clamp inhibits ATP hydrolysis required for initiation of replication.
Which of the above statements are NOT true?
a.
A and B
b.
B and C
c.
C and D
d.
D and A
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Q86
mcq
In *E. coli*, though DNA polymerase I (Pol I) plays an essential role in the replication process, it is not the major polymerase. Instead, the enzyme responsible for advancement of replication fork is Pol III. From the four DNA structures (A, B, C and D) given below, students made several interpretations about the shorter extended by Pol I and/or Pol III.
Which one of the interpretation written below is correct?
a.
A will be extended by Pol III but not by Pol I.
b.
Neither B nor C will be extended by either Pol I or Pol III.
c.
C will be extended by both Pol I and Pol III.
d.
D will be extended only by Pol I, but not by Pol III.
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Q87
mcq
tRNA genes of a Gram positive bacteria were sequenced. While some of the genes possessed sequence corresponding to the -CCA end of the tRNA, others did not. Interestingly, even the genes that lacked the sequence corresponding to the -CCA end of the tRNA were found to code for a functional tRNA. This is because
a.
the -CCA end in the tRNA is not essential for its function.
b.
the genes that do not possess sequence corresponding to the -CCA ends of the tRNA are repaired prior to their transcription.
c.
the -CCA end is added to the tRNA during their maturation.
d.
the primary transcripts of the genes lacking sequence corresponding to the - CCA end are subjected to g-RNA mediated editing prior to their maturation.
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Q88
mcq
A construct (shown below) was generated to access the activity of bidirectional promoter (A and B) which has a common regulatory DNA element (X). The construct was used to transform *E. coli*.
The activity of the promoter (as shown in the graph below) is recorded in the presence of increasing levels of an *E. coli* encoded regulatory protein which binds to DNA element X. The above experiment is repeated in a mutant E. coli with mutation which abolishes binding of the regulatory protein to element X. Which one of the following graphs best the activity of the reporter genes in mutant strain?
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Q89
mcq
In a type of signal transduction pathway, ligand binding to a receptor triggers activation of a receptor-associated kinase. This kinase may be an intrinsic part of the receptor protein or tightly bound to the receptor. Receptors in which the tyrosine kinase is an intrinsic part of it's polypeptide chain are called the receptor tyrosine kinase (RTK). Which one of the following statements regarding RTK is INCORRECT?
a.
All RTKs have three essential components: an extracellular domain containing ligand binding site, a transmembrane domain and a cytoplasmic segment that includes a domain with protein tyrosine kinase activity.
b.
Most RTKs are monomeric and ligand binding to the extracellular domain induces formation of receptor dimers.
c.
All cytokine receptors belong to RTKs and cytokine binding activates tyrosine kinase and receptor dimerization.
d.
Ligand binding to RTK leads to autophosphorylation of the protein tyrosine kinase in the cytoplasmic domain. The activated kinase then phosphorylates several tyrosine residues in the receptor's cytoplasmic domain.
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Q90
mcq
Two classes of genes - proto-oncogene and tumor suppressor gene usually contribute to the development of cancer. Following are some of the statements regarding both the genes.
A. Proto-oncogenes result in the development of cancer by gain-of function mutation whereas tumor suppressor gene leads to cancer development by loss-of-function mutation.
B. Proto-oncogenes result in development of cancer by loss-of function mutation whereas tumor suppressor gene leads to cancer development by gain of-function mutation.
C. Mutation in both the alleles of a protooncogene is required for induction of cancer whereas mutation in one of the two alleles in tumor suppressor gene is sufficient for promoting tumorigenesis.
D. Mutation in one of the two alleles in proto-oncogene is sufficient for induction of cancer whereas mutation in both the alleles of a tumor suppressor gene is required for promoting tumorigenesis.
Which combinations of the above statements are true for both the genes?
a.
A and B
b.
A and C
c.
A and D
d.
B and C
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Q91
mcq
Two important features which aid the development of a tumor and its metastasis are epithelial-to-mesenchymal transition and angiogenesis. A student tested four cell lines to determine their invasiveness and proliferation capability by checking the expression of VEGF-A, TWIST and Cyclin D1. Which one of the following figures is most likely to exhibit the characteristics of a highly metastatic cancer cell?
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q92
mcq
Several types of molecules including the transmembrane glycoproteins can function as matrix receptors and co-receptors. However, the principal receptors on animal cells for binding most extracellular matrix proteins are the integrins. Which of the following statements is NOT true for integrins?
a.
Integrins are transmembrane linker proteins that link to the cytoskeleton.
b.
An integrin molecule is composed of two non-covalently associated glycoprotein subunits and . Both subunits span the cell membrane, with short intracellular C-terminal tails and large N-terminal extracellular domains.
c.
The extracellular portion of the integrin dimer binds to specific carbohydrate residues in extracellular matrix proteins or to ligands on the surface of other cells.
d.
The intracellular portion binds to a complex of proteins that form a linkage to the cytoskeleton.
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Q93
mcq
Major histocompatibility complex (MHC) molecules are encoded by a cluster of genes called MHC locus. There are reveral reasons why an MHC molecule on the surface of a cell is important. Which one of the following reasons is INCORRECT?
a.
To display self class I to demonstrate that the cell is normal and healthy.
b.
To display foreign-peptide in class I to show that the cell is infected and to engage with T helper cells.
c.
To display a self-peptide in class I and II to test developing T cells for autoreactivity.
d.
To display a self-peptide in class I and II to maintain tolerance to self-proteins.
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Q94
mcq
Oncogenic viruses could have either DNA or RNA genomes. Listed below are some oncogenic viruses (Column A), their genome types (Column B) and the cancers caused by these viruses (Column C).
\begin{tabular}{|l|l|l|}
\hline
\multicolumn{1}{|c|}{\textbf{A}} & \multicolumn{1}{|c|}{\textbf{B}} & \multicolumn{1}{|c|}{\textbf{C}} \\
\hline
(a) Hepatitis B & (i) DNA & ($x$) Burkitt's lymphoma \\
(b) Epstein-Barr Virus & (ii) RNA & ($y$) T cell leukaemia \\
(c) HTLV & & ($z$) Hepatocellular carcinoma \\
\hline
\end{tabular}
Find out the correct combination.
a.
(a) (i) (x), (b) (ii) (y), (c) (ii) (z)
b.
(a) (ii) (y), (b) (i) (z), (c) (ii) (x)
c.
(a) (ii) (y), (b) (ii) (z), (c) (i) (y)
d.
(a) (i) (z), (b) (i) (x), (c) (ii) (y)
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Q95
mcq
Identification of genes that are associated with the development of male and/or female gametophyte and embryogenesis in plants is facilitated by T-DNA mediated insertional mutagenesis. In an experiment, a transgenic plant was generated by insertion of T-DNA (containing a Kanamycin-resistance gene) into a gene "A". Self pollination of the $\text{T}_0$ plant generated $\text{F}_1$ progeny that segregated in a $2 : 1$ ratio for resistance:sensitivity to Kanamycin. These observations indicate that
a.
the mutant allele did not segregate from the wild type allele.
b.
mutation in gene "A" induces lethality in the male gametophyte.
c.
mutation in gene "A" induces lethality in the female gametophyte.
d.
mutation in gene "A" induces zygotic lethality.
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Q96
mcq
During vulva development in *C. elegans*, the anchor cell produces Lin-3 protein which interacts with the Let-23 protein present on the six vulval precursor cells (VPCs) that form an equivalence group. The central lineage cell ($\text{P}_6\text{.p}$) adopts the primary fate, the adjacent VPCs ($\text{P}_5\text{.p}$ and $\text{P}_7\text{.p}$) adopt the secondary fate and the rest VPCs adopt the tertiary fate. Few mutants (Column A) and phenotypes (Column B) are listed in the table given below.
\begin{tabular}{|l|l|l|l|}
\hline
& \textbf{Column A} & & \textbf{Column B} \\
\hline
A. & Loss of function of \textit{lin-3} & i. & P5.p, P6.p and P7.p adopt primary \\
& & & fate, P4.p and P8.p adopt secondary fate \\
\hline
B. & Loss of function of \textit{lin-3} and & ii. & Multivulva \\
& gain of function of \textit{let- 23} & & \\
\hline
C. & Reduced function of \textit{lin-3} & iii. & $\text{P}_6\text{.p}$ adopt primary fate and the rest \\
& & & of the VPCs adopt tertiary fate \\
\hline
D. & Overexpression of \textit{lin-3} & iv. & All VPCs adopt tertiary fate \\
\hline
\end{tabular}
Match the correct mutant with the observed phenotype.
a.
A-iv, B-ii, C-iii, D-i
b.
A-iv, B-iii, C-i, D-ii
c.
A-ii, B-iii, C-iv, D-i
d.
A-iii, B-i, C-ii, D-iv
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Q97
mcq
*C. elegans* embryo uses both autonomous and conditional modes of specification. Conditional specification at the 4-cell stage can be seen in the development of the endoderm cell lineage and also in the establishment of dorsal-ventral axis. Following are few statements regarding this:
A. If the P2 cell is removed at the early 4-cell stage, the EMS cell will divide into two MS cells and no endoderm will be made.
B. In *pop-1* deficient embryos, both EMS daughter cells become E cells.
C. When the position of ABa and ABp was reversed, their fates get reversed and no normal embryo forms.
D. In embryos whose mother have mutant *glp-1*, ABp is transformed into ABa cell.
Which of the above statements are true?
a.
A, B and D
b.
A, B and C
c.
B, C and D
d.
A, C and D
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Q98
mcq
Following are the events that might take place during dorso-ventral axis specification in early embryonic development of *Drosophila*:
A. 'Torpedo' receptor activation
B. 'Pipe' synthesis
C. A cascade of protease activity
D. 'Cactus' dephosphorylation
E. Entry of 'Dorsal' in the nuclei of syncytial blastoderm stage embryo.
Which combination of the above events will occur in the presumptive dorsal side of the embryo deficient in maternal *gurken*?
a.
A only
b.
B and C only
c.
B, C and E only
d.
B, C, D and E only
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Q99
mcq
What would be the effect on newt limb regeneration, if more than $90\%$ of the nerve supply is severed before amputation?
a.
The apical ectodermal cap stimulates growth of the blastema by secreting FGF8 but regeneration does not take place.
b.
Limb regeneration will take place and form a limb with no nerve supply.
c.
Outgrowth will occur but the identity of the limb formed will be lost with no clear anterior-posterior polarity.
d.
Limb regeneration with nerve supply will take place.
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Q100
mcq
Fertilization in sea urchin involves interaction of sperm Bindin with its receptor EBR1, a $350\text{ kDa}$ glycoprotein on the egg vitelline membrane. The plot given below shows the status of membrane potential and levels of EBR1, $\text{Na}^+$ and $\text{K}^+$ in an unfertilized egg.
Which one of the following graphs best represents the condition within an egg 1-3 seconds after fertilization?
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Q101
mcq
A specific Mitogen Activated Protein Kinase (MAPK) cascade comprising MEKK1 (a MAP3K), MKK1 (a MAP2K) and MPK6 (a MAPK) is activated sequentially in that order in Arabidopsis plants upon perceiving certain abiotic stress stimuli. The activated MPK6 phosphorylates and activates a transcription factor 'X', thereby making plant tolerant to the abiotic stress. Two different variants of MKK1 protein, a kinase inactive (KI) and a constitutively active (CA) forms were expressed independently in $mkk1$ mutant Arabidopsis plant. Considering above facts, which one of the following statements is CORRECT?
a.
'X' will be activated even in the absence of stimuli in CA plants
b.
'X' will not be activated in the absence of stimuli in CA plants
c.
'X' will be activated in the absence of stimuli in KI plants
d.
The KI plants will be tolerant to the abiotic stress.
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Q102
mcq
Given below are some statements on secondary metabolites in plants.
A. Glucosinolates are synthesized by elongation in the length of side chains of their precursor amino acids.
B. All terpenes produced in herbs and spices are sticky, oily liquids which reduces the palatability (edible value) of these plants.
C. Cyanogenic glycosides are produced and stored in a toxic form in plants and are therefore more effective in defense against invading pathogens and herbivores.
D. The defense molecules, alkaloids (or their precursors), are gathered from plants and used by some insects for their own protection against predators.
Which one of the following represents correct statements?
a.
B and C only
b.
A and B only
c.
C only
d.
A and D only
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Q103
mcq
A researcher developed quadruple mutant that disrupted the function of all phytochrome interacting factor (PIF) family members. The following hypotheses were proposed regarding the phenotype of the mutant plants when grown in dark:
A. Plants would show short hypocotyls
B. Plants would be etiolated
C. Light induced genes would be activated
D. The cotyledons would be open
Which one of the following combinations of the above hypotheses is correct?
a.
A, B and C
b.
A, B and D
c.
A, C and D
d.
B, C and D
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Q104
mcq
The photon intensity captured by green plants is used in the following processes:
(i) Photosynthesis
(ii) Generation of heat
(iii) Production of toxic products such as superoxide, singlet oxygen etc.
(iv) Damage to D1 protein of PSII
Based on the above facts, photoinhibiton will happen when the
a.
entire photon intensity is used for photosynthesis
b.
excess photon intensity is completely used for heat generation
c.
excess photon intensity is used for heat generation and formation of toxic products
d.
excess photon intensity leads to the damage of D1 protein
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Q105
mcq
With reference to plant biotic interactions, match the terms of Column I with the most appropriate term of Column II
\begin{tabular}{|l|l|l|l|}
\hline
& \textbf{Column I} & & \textbf{Column II} \\
\hline
A. & Phytoliths of Poaceae & (i) & Phloem feeders \\
B. & Salicylic acid signalling pathway & (ii) & Decrease in stomatal aperture \\
C. & MAMP & (iii) & R genes/NBS-LRR receptor \\
D. & Effector-triggered immunity & (iv) & Mechanical barrier to herbivory \\
\hline
\end{tabular}
a.
A - (ii), B - (iv), C - (i), D - (iii)
b.
A - (iii), B - (i), C - (ii), D - (iv)
c.
A - (iv), B - (ii), C - (iii), D - (i)
d.
A - (iv), B - (i), C - (ii), D - (iii)
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Q106
mcq
Transgenic tobacco plants over-expressing isopentenyl transferase ($IPT$) under the control of promoter region of Senescence-Associated Receptor kinase ($\text{P}_{\text{SARK}}$) were exposed to drought for 15 days followed by re-watering for 7 days. The following hypotheses were proposed regarding changes in the transgenic plants at the end of 7 days of re-watering:
A. The plants would be wilted and fail to survive.
B. The plants would be healthy and survive.
C. The plants would show higher production of cytokinin compared to wild type plants.
D. The plants would show higher production of absicic acid compared to wild type plants.
Which one of the following combinations of the above hypotheses is correct?
a.
A and C
b.
A and D
c.
B and C
d.
B and D
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Q107
mcq
The following statements describe the possible functions of the outer hair cells (OHC) of organ of Corti:
A. The outer hair cells (OHC) are depolarized or hyperpolarized depending on the direction of movement of stereocilia.
B. The OHC are lengthened in depolarization and shortened in hyperpolarization
C. The OHC decrease the amplitude and clarity of sound by shortening and lengthening.
D. The efferent nerve fibers of olivocochlear bundle modulate the sensitivity of the OHC
E. The effect of stimulation of olivocochlear bundle on the OHC is excitatory.
Which one of the options given below represents the correct statements?
a.
A and B
b.
C and D
c.
A and D
d.
D and E
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Q108
mcq
The pacemaker cells of sinoatrial node (SA node) are inhibited by the stimulation of vagus nerve. The probable mechanisms of this inhibition are stated as follows:
A. The acetylcholine- regulated $\text{K}^+$ channels are activated
B. The outward $\text{K}^+$ causes hyperpolarization of pacemaker cells
C. The inward "funny current" of pacemaker potential is increased
D. The increased intracellular cAMP, induced by activation of $\text{M}_2$ muscarinic receptors, slows the opening of $\text{Ca}^{++}$ channels
Choose the answer with correct statements.
a.
A and C
b.
B and C
c.
A and B
d.
C and D
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Q109
mcq
In the glomerular capillary (GC), fluid moves into Bowman's capsule through its almost entire length. But in the muscle capillary (MC), fluid moves into interstitial space at its arteriolar end. The difference between these two capillaries is explained in the following proposed statements:
A. Afferent and efferent arterioles are present on the two ends of GC, but in MC, arteriole and venule are present on two ends.
B. The hydrostatic pressure in GC is higher than that in MC.
C. The efferent arteriole in GC has a relatively low resistance, but venules in MC has a high resistance.
D. The difference of hydrostatic pressure between two ends of GC is relatively more but it is negligible in MC.
E. The difference of oncotic pressure between two ends of MC is negligible but it is relatively more in GC.
F. The net filtration pressure falls to zero at the efferent end of GC but it is $9\text{ mm Hg}$ inward at the venular end of MC.
Which of the above statements are INCORRECT?
a.
A and B
b.
C and D
c.
E and F
d.
B and F
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Q110
mcq
When a skeletal muscle was passively stretched, it contracted reflexly. However, when the muscle was over stretched in this way it showed sudden cessation of contraction followed by relaxation. The following statements provided the possible explanation of these observations:
A. The passive stretching of muscle caused stretching of muscle spindle
B. The over stretching of muscle stimulated Golgi tendon organ
C. Group 1b sensory nerve fibers were stimulated by stretching of muscle spindle
D. Group 1b sensory nerve fibers stimulated $\alpha$-motor neurons that supplied the muscle from which these fibers arose.
E. Group 1a sensory nerve fibers were connected to Golgi tendon organ.
F. The stimulation of group 1a sensory fibers led to the production of IPSP on the $\alpha$-motor neurons that supplied the muscle from which these fibers arose.
Which of the above statement(s) is/are correct?
a.
A and B
b.
C and D
c.
E and F
d.
C and F
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Q111
mcq
Relative rates of red blood cells production in bone marrow of different bones of different ages are shown below:
Identify the correct figure.
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q112
mcq
The above figure depicts the regulation of hypothalamo-pituitary-adrenal (HPA) axis. Changes in cortisol level in Addison's disease can lead to
a.
suppressed immune system and increased blood glucose level
b.
gain of body weight and lightening of skin
c.
loss of body weight, reduced blood glucose level and hyperpigmentation
d.
increased blood glucose and activated immune system
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Q113
mcq
The following table shows mapping data from three interrupted mating experiments using three different Hfr strains and an $\text{F}^-$ strain:
Appearance of genes in $\text{F}^-$ cells
| | | | | | | |
| :--- | :--- | :---: | :---: | :---: | :---: | :---: |
| Hfr 1 | Genes | $\text{e}^+$ | $\text{f}^+$ | $\text{c}^+$ | $\text{d}^+$ | $\text{b}^+$ |
| | Time | 6 | 24 | 34 | 49 | 54 |
| Hfr 2 | Genes | $\text{b}^+$ | $\text{d}^+$ | $\text{c}^+$ | $\text{f}^+$ | $\text{g}^+$ |
| | Time | 1 | 6 | 21 | 31 | 63 |
| Hfr 3 | Genes | $\text{d}^+$ | $\text{c}^+$ | $\text{f}^+$ | $\text{e}^+$ | $\text{g}^+$ |
| | Time | 4 | 19 | 29 | 47 | 61 |
(Time is represented in minutes)
The distance between are derived:
The order of genes is
A. e g b d c f
B. f g b d c e
The following answers
C. f and g is 32 min is 30 min and between f and b
D. c and e is 28 min is 20 min and between b and c
The correct combination of answers is
a.
A, C and D
b.
B and C
c.
A and B
d.
B and D
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Q114
mcq
The inheritance of a given disorder is recorded in three small families shown below:
Based on the above limited information, which one of the following inheritance pattern best explains the observations?
a.
X-linked recessive
b.
X-linked dominant
c.
Autosomal recessive
d.
Autosomal dominant
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Q115
mcq
A new mutant called early ripening (EL) is identified in a plant. The wild type phenotype is late ripening (LR). Further DNA marker(s) is/are observed to be polymorphic between EL and LR plants. A cross was made between pure lines of LR and ER. The F1 progeny was test crossed and its progeny was analyzed. The parental, $\text{F}_1$ and progeny of test cross were also analyzed for the DNA marker. The table below summarizes the phenotype of the progeny and the pattern of DNA marker observed in each case:
Based on the above information, the following statements were made:
A. LR is dominant to ER
B. The DNA marker used is a dominant marker
C. The DNA marker is linked to the phenotype
Which of the above statements are correct?
a.
A only
b.
A and B only
c.
A and C only
d.
A, B and C only
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Q116
mcq
In Burkitt's Lymphoma a reciprocal translocation between chromosome 8 and 14 is observed. If an individual is heterozygous for this translocation, the consequence in meiosis will be as follows:
A. Four chromosomes, i.e., normal chromosome 8 and 14, and translocated chromosome 8 and 14, pair together
B. The two normal chromosomes 8 and 14, and two translocated chromosomes pair separately
C. All gametes produced from this meiosis are non-viable as they have deletions and duplications
D. In one of the cross configurations called "alternate segregation" all gametes having normal or translocated chromosomes, survive
E. The gametes having normal chromosomes only survive while all gametes having translocated chromosomes are non-viable, hence the translocations are used as crossover suppressors
Which of the following combinations best describes the meiotic consequences for the translocation described above?
a.
B and E
b.
B, C and E
c.
A, C and E
d.
A and D
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Q117
mcq
In *Drosophila*, Bar eye (B) is a dominant mutation while miniature wing (m) and yellow body colour (y) are recessive mutations. Heterozygous females for these mutations were crossed to normal eyed miniature winged and yellow body coloured males. Assume the following progeny was obtained:
\begin{tabular}{|c|c|}
\hline
Phenotypes & Number \\
\hline
$B^+ m^+ y^+$ & 30 \\
$B\ m\ y^+$ & 25 \\
$B\ m^+ y^+$ & 165 \\
$B^+ m\ y^+$ & 120 \\
$B\ m\ y$ & 20 \\
$B^+ m\ y$ & 185 \\
$B\ m^+ y$ & 110 \\
$B^+ m^+ y$ & 45 \\
\hline
\end{tabular}
Based on the results obtained, the order of genes will be:
A. $\text{B m y}$
B. $\text{m B y}$
The genetic distance between B and y will be:
C. $40\text{ cM}$
D. $17.1\text{ cM}$
The correct combination of answer is
a.
A and C
b.
B and C
c.
A and D
d.
B and D
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Q118
mcq
Two inbred lines of beans were intercrossed. In $\text{F}_1$ the variance in bean length was measured as 2.0. The $\text{F}_1$ was selfed to obtain $\text{F}_2$ and the variance in bean length in $\text{F}_2$ was 7.0. The broad heritability of bean length in the $\text{F}_2$ population will be:
a.
0.75
b.
9.0
c.
5.0
d.
0.71
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Q119
mcq
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.
a.
*Terminalia bellirica*, *Euphorbia hirta*, *Nerium indicum*
b.
*Mallotus philippense*, *Ficus religiosa*, *Ricinus communis*
c.
*Mallotus philippense*, *Acalypha indica*, *Emblica officinalis*
d.
*Acalypha indica*, *Ricinus communis*, *Mangifera indica*
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Q120
mcq
Given below are statements on key character-istics of two fungal lineages.
(A) Microsporidia do not have truemitochondria
(B) Most chytrids produce flagellated gametes
(C) Microsporidia are usually free-living
(D) Chytrids reproduce sexually without adikaryon stage
Choose the combination with correct statements
a.
A, B and C only
b.
A, B and D only
c.
B, C and D only
d.
A and B only
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Q121
mcq
Match the two columns that represent plant organs (I) and parts within these organs (II).
\begin{tabular}{ll}
\textbf{Column I} & \textbf{Column II} \\
A Carpel & (i) Petals, corolla \\
B Perianth & (ii) Vegetative cell, generative cell \\
C Microsporocyte & (iii) Stigma, style, ovary \\
D Megasporocyte & (iv) Antipodal cells, polar nuclei, synergid cells
\end{tabular}
a.
A-(i); B-(iii); C-(ii); D-(iv)
b.
A-(iii); B-(iv); C-(i); D-(ii)
c.
A-(i); B-(iii); C-(iv); D-(ii)
d.
A-(iii); B-(i); C-(ii); D-(iv)
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Q122
mcq
Given below are larval stages and phylum to which they belong. Select the INCORRECT combination.
a.
Parenchyma and Amphiblastula - Phylum Porifera
b.
Bipinnaria and Auricularia- Phylum Echinodermata
c.
Tornasia and Axolotl- Phylum Hemichordata
d.
Planula and Ephyra- Phylum Cnidaria
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Q123
mcq
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?
a.
stapes – articular; incus – quadrate; malleus – hyomandibular.
b.
stapes – quadrate; incus – articular; malleus – hyomandibular
c.
stapes – articular; incus – hyomandibular; malleus – quadrate
d.
stapes – hyomandibular; incus – quadrate; malleus – articular
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Q124
mcq
Three species M, N and O when grown independently in a laboratory showed typical logistic growth curves. However, when grown in pairs, the following growth curves were observed.
What interpretation regarding the interspecific relationship between M, N and O can be deduced from the above observations?
a.
N predates over O and therefore can also predate on M.
b.
N is competed out by M and O.
c.
N and O possibly have a prey-predator relationship.
d.
M and O exhibit prey-predator relationship.
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Q125
mcq
Temporal isolation in breeding seasons between closely related species leads to reproductive isolation. Given below are breeding seasons of different species of frogs.
Which of the above plots represents temporal isolation in breeding seasons among closely related sympatric species?
a.
Plot A
b.
Plots A and B
c.
Plots B and C
d.
Plots A and C
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Q126
mcq
Given below are the population pyramids of three different populations A, B and C depicting the relationship between birth and death rates in each.
Based on the population pyramids given above, which one of the following is INCORRECT?
a.
Population B has slower growth rate than population A.
b.
Population C has birth rate higher than its death rate.
c.
Population A represents a rapidly growing population.
d.
Population B has the highest death rate among the three populations.
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Q127
mcq
Given below are names of some of the National Parks of India and their key protected animals.
\begin{tabular}{|l|l|l|l|}
\hline
& \textbf{Name of the National Park} & & \textbf{Key protected animal} \\
\hline
A & Dibru-Saikhowa National Park, Assam & (i) & Indian Rhinoceros \\
\hline
B & Jaldapara National Park, West Bengal & (ii) & Hangul \\
\hline
C & Mukurthi National Park, Tamil Nadu & (iii) & Feral Horse \\
\hline
D & Dachigam National Park, Jammu and Kashmir & (iv) & Asiatic Lion \\
\hline
E & Gir Forest National Park, Gujarat & (v) & Nilgiri Tahr \\
\hline
\end{tabular}
Based on the table given above, which of the following options represents the correct match?
a.
A-(iii); B-(i); C-(iv); D-(ii); E-(v)
b.
A-(i); B-(ii); C-(v); D-(iii); E-(iv)
c.
A-(i); B-(ii); C-(iii); D-(iv); E-(v)
d.
A-(iii); B-(i); C-(v); D-(ii); E-(iv)
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Q128
mcq
Given below are two patterns of ecological succession. Four species are represented by A, B, C and D. An arrow indicates "is replaced by".
In the context of ecological succession, which of the following statements is INCORRECT with respect to the figures given above?
a.
Model - X represents facilitation model and Model - Y represents tolerance model.
b.
Model - X represents tolerance model and Model - Y represents inhibition model.
c.
As per Model - Y, C can out-compete B but can also invade a habitat in their absence.
d.
As per the Model - X, A makes the environments more suitable for B to invade.
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Q129
mcq
Given below are the species accumulation curves and rarefaction curves measured in an ecological community.
Which one of the following statements is INCORRECT about the two curves?
a.
Species accumulation curve moves from left to right and rarefaction curve moves from right to left.
b.
Species accumulation curve represents the total species richness of the assemblage.
c.
Rarefaction curve represents the mean of repeated resampling of all pooled samples.
d.
Rarefaction curve is the realized accumula- tion value of the total species in a community.
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Q130
mcq
A gene 'X' in \textit{Drosophila} contributes to inviability of hybrids. The phylogeny below shows the evolutionary history of gene 'X' and on each branch the numbers indicate the non-synonymous/synonymous substitutions.
Based on the above information, select the correct statement from the choices below:
a.
High proportion of non-synonymous changes at A indicates evolution by natural selection.
b.
High proportion of synonymous changes at A indicates absence of natural selection.
c.
Equal proportion of non-synonymous and synonymous changes at B indicates deleterious selection.
d.
Low proportion of non-synonymous changes at C indicates positive selection.
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Q131
mcq
When the electrical response of the two receptors A1 and A2 in a noctuid moth that was exposed to a variety of sounds was measured, it produced the following patterns:
Given this, which one of the following statements is INCORRECT:
a.
The A1 receptor is sensitive to sound of low to high intensity.
b.
A2 receptor begins to produce action potentials only when a sound is loud.
c.
Both the receptors have similar response to high intensity sound.
d.
The A1 receptor fires much more frequently to steady, uninterrupted sounds than to high frequency pulses of sound.
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Q132
mcq
A barn owl sits on its perch 10m above ground. It hears a mouse underneath on the ground at an angle $\alpha$ as shown in the figure below.
The error range with which it can locate the mouse on the ground is given by
a.
$\tan \alpha = \text{X/H}$
b.
$\cos \alpha = \text{X/H}$
c.
$\sin \alpha = \text{X/H}$
d.
$\cos \alpha = \text{X/C}$
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Q133
mcq
A 20-week old infant was exposed to the following stimuli and the responses were measured.
Based on the response patterns shown above to the given stimuli, select the correct theory that best describes the observed responses.
a.
Heterogenous summation
b.
Gestalt principle
c.
Supernormal stimuli
d.
Sign stimulus
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Q134
mcq
When James R Brown and W Ford Doolittle (1997) reconstructed the tree of life using a variety of different genes, they found that different genes gave fundamentally different phylogenies as shown below. Note that the genes are unique to the specific trees.
From the given options select the process that best explains the observed discrepancies between the trees.
a.
polyploidization
b.
horizontal gene transfer
c.
allopatric speciation
d.
localized extinctions
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Q135
mcq
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 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:
a.
behavioural isolation through mimicry
b.
mechanical isolation through mimicry
c.
temporal isolation
d.
habitat isolation
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Q140
mcq
To achieve a best resolution using a fluorescence microscope, what combination of wavelength of emitted light ($\lambda$), refractive index and the angle ($2\theta$) by which light enters into the microscope would be the best choice for the user:
a.
$\lambda = 405$; refractive index=$1.33$; $2\theta = 90^\circ$
b.
$\lambda = 420$; refractive index=$1.51$; $2\theta = 180^\circ$
c.
$\lambda = 520$; refractive index=$1.51$; $2\theta = 90^\circ$
d.
$\lambda = 405$; refractive index=$1.51$; $2\theta = 180^\circ$
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Q141
mcq
Given below are spatial and temporal techniques (column I) used to detect brain activity (column II)
\begin{tabular}{|l|l|l|l|}
\hline
\multicolumn{2}{|c|}{\textbf{Column I}} & \multicolumn{2}{|c|}{\textbf{Column II}} \\
\hline
A & Functional magnetic resonance imaging & (i) & Uses short-lived radioactive material to map functional processes in brain \\
\hline
B & Positron emission tomography & (ii) & Measure the fluctuation of dipole voltage in neurons of brain \\
\hline
C & Computed tomography & (iii) & Detects changes in blood oxygenation and flow due to neural activity \\
\hline
D & Electroencephalogram & (iv) & Images of brain obtained by differential absorption of X-rays \\
\hline
\end{tabular}
Select the correct set of combination
a.
A-(i), B-(ii), C-(iii), D-(iv)
b.
A-(iii), B-(i), C-(iv), D-(ii)
c.
A-(iv), B-(iii), C-(ii), D-(i)
d.
A-(ii), B-(iv), C-(i), D-(iii)
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Q142
mcq
Following observations are made regarding a peptide sequence.
• The peptide is inert to Ellman's reagent. However, on reacting with $\beta$-mercaptoethanol, the peptide gives a positive Ellman's test.
• The peptide sequence gives a broad minimum around $211\text{ nm}$ in the CD spectrum.
• With increasing concentration of the peptide, the melting temperature of the peptide increases.
• On treating the peptide with $\text{D}_2\text{O}$, half the total number of amides get exchanged.
Which one of the following statements is correct?
a.
It is an $\alpha$-helical peptide that undergoes aggregation
b.
It is an $\alpha$-helical disulfide bridged peptide that undergoes aggregation
c.
It is an $\beta$-hairpin peptide, which is stabilized by a disulfide bridge
d.
The peptide is composed of an $\alpha$-helix and $\beta$-sheet connected by a disulfide bridge
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Q143
mcq
If a metabolically active cell is challenged with $^{55}\text{Fe}$ radioisotope label, which of the following proteins CANNOT be detected by autoradiography?
a.
Aconitase and lipoic acid synthase
b.
Cytochrome C and DNA primase
c.
Calmodulin and Calcineurin
d.
Myoglobin and Homoaconitase
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Q144
mcq
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.
a.
A and B only
b.
C and D only
c.
B and C only
d.
A and D only
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Q145
mcq
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 statements.
a.
B, C, E
b.
A, B, E
c.
A, C, D
d.
B, D, E
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