CSIR NET · Life Sciences
June
2015
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111 questions
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Q21
mcq
A 1% (w/v) solution of a sugar polymer is digested by an enzyme ($20\mu\text{g}$, $\text{MW} = 200{,}000$). The rate of monomer sugar ($\text{MW} = 400$) liberated was determined to have a maximal initial velocity of $10\text{ mg formed/min}$. The turnover number ($\text{min}^{-1}$) will be
a.
$5 \times 10^4$
b.
$2.5 \times 10^{-2}$
c.
$4.0 \times 10^{-6}$
d.
$2.5 \times 10^5$
Correct Answer
Step-by-Step AI Explanation
Verified Method
Turnover number ($k_{\text{cat}}$) is given by $V_{\max} / [E_t]$.
1. Calculate moles of enzyme ($E_t$):
$$\text{Mass of enzyme} = 20\,\mu\text{g} = 20 \times 10^{-6}\text{ g}$$
$$\text{Moles of enzyme} = \frac{20 \times 10^{-6}\text{ g}}{200{,}000\text{ g/mol}} = 10^{-10}\text{ mol}$$
2. Calculate moles of monomer formed per minute at $V_{\max}$:
$$\text{Mass of monomer/min} = 10\text{ mg/min} = 10 \times 10^{-3}\text{ g/min}$$
$$\text{Moles of monomer/min} = \frac{10 \times 10^{-3}\text{ g/min}}{400\text{ g/mol}} = 2.5 \times 10^{-5}\text{ mol/min}$$
3. Calculate turnover number ($k_{\text{cat}}$):
$$k_{\text{cat}} = \frac{2.5 \times 10^{-5}\text{ mol/min}}{10^{-10}\text{ mol}} = 2.5 \times 10^5\text{ min}^{-1}$$
Therefore, choice D is correct.
Q22
mcq
In an alpha helical polypeptide, the backbone hydrogen bonds are between
a.
$\text{NH of } n \text{ and } \text{CO of } n + 4 \text{ amino acids}$
b.
$\text{CO of } n \text{ and } \text{NH of } n + 3 \text{ amino acids}$
c.
$\text{CO of } n \text{ and } \text{NH of } n + 4 \text{ amino acids}$
Correct Answer
d.
$\text{NH of } n \text{ and } \text{CO of } n + 3 \text{ amino acids}$
Step-by-Step AI Explanation
Verified Method
In a standard $\alpha$-helix, backbone hydrogen bonds are formed between the carbonyl oxygen ($\text{C=O}$) of residue $n$ and the amide hydrogen ($\text{N-H}$) of residue $n+4$ along the polypeptide chain.
Q23
mcq
Following are three single stranded DNA sequences that form secondary structures.
I. ATTGAGCGATCAAT
II. ATTGAGCGATATCAAT
III. AGGGAGCGATCCCT
Based on their stability, which one is correct?
a.
$\text{I} = \text{II} = \text{III}$
b.
$\text{III} > \text{I} > \text{II}$
Correct Answer
c.
$\text{II} > \text{III} = \text{I}$
d.
$\text{II} > \text{III} > \text{I}$
Step-by-Step AI Explanation
Verified Method
These single-stranded sequences can fold to form hairpin (stem-loop) structures through self-complementarity:
- Sequence I (14 nt): `5'-ATTGA-GCGA-TCAAT-3'`. The stem is formed by pairing `ATTGA` with `TCAAT` (all 5 base pairs: A-T, T-A, T-A, G-C, A-T), with a loop of 4 nt (`GCGA`). It contains 1 G-C pair and 4 A-T pairs.
- Sequence II (16 nt): `5'-ATTGA-GCGAT-ATCAAT-3'`. It forms the same stem with a longer loop or slightly distorted stem-loop, having lower stability than I due to increased loop entropy or mismatched base.
- Sequence III (14 nt): `5'-AGGGA-GCGA-TCCCT-3'`. The stem is formed by pairing `AGGGA` with `TCCCT` (all 5 base pairs: A-T, G-C, G-C, G-C, A-T), containing 3 G-C pairs and 2 A-T pairs.
Since G-C pairs are held by three hydrogen bonds compared to two for A-T pairs, the stem in sequence III is the most stable. Sequence I and II have the same stem composition (1 G-C, 4 A-T), but sequence I has a more optimal smaller loop (4 nt) compared to sequence II (6 nt loop), making sequence I more stable than sequence II (larger loops are thermodynamically less stable due to greater entropic penalty). Thus, the order of stability is $\text{III} > \text{I} > \text{II}$.
Q24
mcq
Which one of the following enzymes is NOT a part of pyruvate dehydrogenase enzyme complex in glycolysis pathway?
a.
Pyruvate dehydrogenase.
b.
Dihydrolipoyl transferase.
c.
Dihydrolipoyl dehydrogenase.
d.
Dihydrolipoyl oxidase.
Correct Answer
Step-by-Step AI Explanation
Verified Method
The pyruvate dehydrogenase complex (PDC) consists of three core catalytic enzymes:
1. $E_1$: Pyruvate dehydrogenase
2. $E_2$: Dihydrolipoyl transacetylase (transferase)
3. $E_3$: Dihydrolipoyl dehydrogenase
'Dihydrolipoyl oxidase' is not a component of the pyruvate dehydrogenase complex.
Q25
mcq
What phenotype would you predict for a mutant mouse lacking one of the genes required for site-specific recombination in lymphocytes?
a.
Decrease in T cell counts
b.
Immunodeficient
Correct Answer
c.
Increase in T cell counts
d.
Increase in B cell counts
Step-by-Step AI Explanation
Verified Method
Site-specific recombination in lymphocytes, specifically V(D)J recombination mediated by RAG1 and RAG2, is essential for the maturation and development of functional B and T cells. A deficiency in any essential gene required for this process prevents the assembly of functional B-cell receptors (immunoglobulins) and T-cell receptors, leading to severe combined immunodeficiency (e.g., as seen in RAG knockout or SCID mice).
Q26
mcq
The key determinant of the plane of cytokinesis in mammalian cells is the position of
a.
chromosomes
b.
central spindle
Correct Answer
c.
centrioles
d.
pre-prophase band
Step-by-Step AI Explanation
Verified Method
In animal/mammalian cells, signals emanating from the central spindle (anaphase spindle midzone) and the astral microtubules determine the site of contractile ring assembly and specify the plane of cytokinesis. The pre-prophase band is found in plant cells, not mammalian cells.
Q27
mcq
Beating of cilia is regulated by
a.
actin
b.
mysoin
c.
cofilin
d.
nexin
Correct Answer
Step-by-Step AI Explanation
Verified Method
Nexin forms interdoublet links between adjacent outer microtubule doublets in the axoneme of cilia and flagella. These elastic nexin linkages convert the dynein-driven sliding of microtubule doublets into the bending motion characteristic of ciliary and flagellar beating.
Q28
mcq
Cystic fibrosis transmembrane conductance regulator (CFTR) is known to control the transport of which ion?
a.
$\text{Ca}^{2+}$
b.
$\text{Mg}^{2+}$
c.
$\text{HCO}_3^-$
d.
$\text{Cl}^-$
Correct Answer
Step-by-Step AI Explanation
Verified Method
The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter-class ion channel that functions primarily as an ATP-gated chloride ($\text{Cl}^-$) channel across epithelial cell membranes.
Q29
mcq
In bacteria, heat-shock response is primarily controlled by
a.
Sigma S ($\sigma^\text{E}$)
b.
Sigma 32 ($\sigma^{32}$)
Correct Answer
c.
Sigma E ($\sigma^\text{E}$)
d.
Sigma 70 ($\sigma^{70}$)
Step-by-Step AI Explanation
Verified Method
In *Escherichia coli* and other bacteria, the cytoplasmic heat-shock response is primarily regulated by the alternative sigma factor $\sigma^{32}$ (encoded by the *rpoH* gene), which directs RNA polymerase to transcribe heat-shock genes (such as molecular chaperones DnaK, DnaJ, GroEL, GroES, and proteases). $\sigma^E$ ($\sigma^{24}$) controls the extracytoplasmic/envelope stress response, $\sigma^S$ ($\sigma^{38}$) regulates the general stationary phase/starvation response, and $\sigma^{70}$ is the primary vegetative housekeeping sigma factor.
Q30
mcq
In type II splicing
a.
a ‘G-OH’ from outside makes a nucleophilic attack on 5'-P of first base of intron,
b.
a free 2'-OH of an internal adenosine makes a nucleophilic attack on 5'-P of first base of intron
Correct Answer
c.
A 3'-OH of an internal adenosine makes a nucleophilic attack on 5'-P of first base of intron
d.
the hydrolysis of last base of exon is carried out by U2/U4/U6
Step-by-Step AI Explanation
Verified Method
Group II intron splicing proceeds via a two-step transesterification mechanism similar to nuclear pre-mRNA splicing. In the first step, the $2'\text{-OH}$ of a specific internal adenosine residue (branch point) within the intron carries out a nucleophilic attack on the $5'$ splice site (the $5'\text{-phosphate}$ of the first nucleotide of the intron), forming a lariat intermediate. Attack by an external guanosine cofactor ('G-OH') occurs in Group I introns, not Group II introns.
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Q31
mcq
Given below are some statements about prokaryotic and eukaryotic mobile genetic elements or transposons.
A. Most mobile genetic elements in bacteria transpose via an RNA intermediate.
B. Most mobile genetic elements in bacteria are DNA.
C. Mobile genetic elements in eukaryotes are only retrotransposons.
D. Both, RNA and DNA transposons are found in eukaryotes.
Choose the correct combination.
a.
A and C
b.
B and C
c.
A and D
d.
B and D
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Q32
mcq
Copying errors occurring during replication are corrected by the proof reading activity of DNA polymerases that recognize incorrect bases
a.
at the $5'$ end of the growing chain and remove them by $5' \rightarrow 3'$ exonuclease activity.
b.
at the $3'$ end of the growing chain and remove them by $5' \rightarrow 3'$ exonuclease activity
c.
at the $3'$ end of the growing chain and remove them by $3' \rightarrow 5'$ exonuclease activity
d.
at the $5'$ end of the growing chain and remove them by $3' \rightarrow 5'$ exonuclease activity
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Q33
mcq
During each cycle of chain elngation in translation, how many conformational changes does the ribosome undergo that are coupled to GTP hydrolysis ?
a.
zero
b.
One
c.
Two
d.
Three
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Q34
mcq
Collagens are the most abundant component of the extracellular matrix. In order to maintain normal physiological processes like wound healing, bone development, etc., which one of the following type of enzymes is MOST important?
a.
Peptidases
b.
Proteases
c.
Amylase
d.
Lipases
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Q35
mcq
Which one of the following events NEVER activates the G-protein coupled receptor for sequestering $\text{Ca}^{2+}$ release?
a.
Interaction of bind in to sperm receptors.
b.
Activation of Frizzled by Wnt.
c.
Cortical reaction blocking polyspermy
d.
DNA synthesis and nuclear envelope breakdown.
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Q36
mcq
The main difference between normal and transformed cells are
a.
immortality and contact inhibition
b.
shorter generation time and cell mobility
c.
apoptosis and tumour suppressor gene hyperfunction
d.
inactivation of oncogenes and shorter cell cycle duration
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Q37
mcq
When bacteria growing at $20^\circ\text{C}$ are warmed at $37^\circ\text{C}$, they are most likely to synthesize membrane lipids with more
a.
short chain saturated fatty acids
b.
short chain unsaturated fatty acids
c.
long chain saturated fatty acids
d.
long chain unsaturated fatty acids
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Q38
mcq
Hydra shows morphallactic regeneration and involves which one of the following signal transduction pathway in its axis formation?
a.
Wnt/$\beta$-catenin pathway
b.
Retinoic acid pathway
c.
FGF pathway
d.
Delta-Notch pathway
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Q39
mcq
The mammalian oocyte prior to sperm entry is arrested at what stage of cell division ?
a.
Prophase of mitosis
b.
Prophase of mitosis I
c.
$\text{G}_1$ phase of mitosis cell cycle
d.
Metaphase of meiosis II
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Q40
mcq
The pluripotency of the inner cell mass in mammals is maintained by a core of. three transcription factors namely,
a.
Oct 4, Sox 2 and Nanog
b.
Oct 4, Sox 2 and Cdx2
c.
Sox 2, Nanog and Cdx2
d.
Oct 4, Cdx2 and Nanog
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Q41
mcq
Which one of the following statements about LEAFY (LFY), a regulatory gene in \textit{Arabidopsis thaliana}, is correct?
a.
LEAFY (LFY) is involved in floral meristem identity
b.
LEAFY (LFY) is involved in leaf expansion.
c.
LEAFY (LFY) ‘is involved in root meristem identity.
d.
LEAFY (LFY) is responsible far far-red light mediated seedling grawth.
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Q42
mcq
The quantum yield of oxygen evolution during photosynthesis drastically drops in far-red light. This effect is known as:
a.
Far red drop.
b.
Red drop.
c.
Blue drop.
d.
Visible spectrum drop.
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Q43
mcq
Dark-grown seedlings display ‘triple response’ when exposed to ethylene. Which one of the following is NOT a part of ‘triple response’?
a.
Decrease in epicotyl elongation.
b.
Rapid unfolding and expansion of leaves.
c.
Thickening of shoot.
d.
Horizontal growth of epicotyl.
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Q44
mcq
Which one of the following compounds is generally translocated in the phloem?
a.
Sucrose
b.
D-Glucose
c.
D-Mannose
d.
D-Fructose
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Q45
mcq
Nitrogen gas is reduced to ammonia by nitrogen fixation method. In order to execute the process, which one of the following compounds is usually required?
a.
ATP
b.
GTP
c.
UDP
d.
ADP
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Q46
mcq
The S wave of normal human ECG originates due to
a.
septal and left ventricular depolarization.
b.
late depolarization of the ventricular walls moving back toward the AV junction.
c.
left to right septal depolarization.
d.
repolarization of atrium.
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Q47
mcq
Which one of the following skeletal muscles of human body contains highest number of muscle fibre in a motor unit?
a.
Muscles of hand
b.
Extraocular muscles
c.
Muscles of leg
d.
Muscles of face.
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Q48
mcq
In which of the following conditions is Basal Metabolic Rate (BMR) the lowest?
a.
Awake and resting
b.
Prolonged starvation
c.
Sleep
d.
Higher environmental temperature
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Q49
mcq
Which one of the following combinations must be present in a steroid receptor that is located in the cytoplasm?
a.
Nuclear export sequence (NES), leucine zipper
b.
NES, zinc finger motif
c.
Nuclear localization sequence (NLS), zinc finger motif
d.
NLS, leucine zipper
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Q50
mcq
Segregation of alleles can occur at Anaphase I or at Anaphase n of meiosis. With reference to this statement, which one of the following organism is an ideal model system for identifying stage of allelic segregation at meiosis?
a.
\textit{Neurospora crassa}
b.
\textit{Saccharomyces cerevisiae}
c.
\textit{Drosophila melanogaster}
d.
\textit{Pisum sativum}
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Q51
mcq
Genes A, B and C. control three phenotypes which assort independently; A plant with the genotype Aa Bb Cc is selfed. What is the probability for progeny which show the dominant phenotype for AT LEAST ONE of the phenotypes controlled by genes A, B and C?
a.
$1/64$
b.
$27/64$
c.
$63/64$
d.
Cannot be predicted
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Q52
mcq
Hybrid dysgenesis in Drosophila is caused by P-elements. Which one of the following crosses between different cytotypes will lead to dysgenesis?
a.
M-cytotype $\text{♀} \times$ M-cytotype $\text{♂}$
b.
M-cytotype $\text{♀} \times$ P-cytotype $\text{♂}$
c.
P-cytotype $\text{♀} \times$ M-cytotype $\text{♂}$
d.
P-cytotype $\text{♀} \times$ P-cytotype $\text{♂}$
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Q53
mcq
In an experiment, clones of a plant is grown in a field. The plants were observed to be of different heights. When a graph was plotted for frequency of plants (Y-axis) against different heights (X-axis), a bell-shaped curve was obtained. From the above, it can be concluded that the observed variation in height is due to
a.
it being a polygenic trait
b.
environmental effect
c.
variation in genotype.
d.
influence of environment on different genotypes
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Q54
mcq
Which one of the following viruses cause acute gastrointestinal illness due to contamination of drinking water?
a.
Norovirus
b.
Poliovirus
c.
Rotavirus
d.
Filoviruses
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Q55
mcq
The phylum in which the animals are bilaterally symmetrical in the larval stage and radially symmetrical in the adult stage is
a.
Coelenterata.
b.
Nematoda.
c.
Mollusca.
d.
Echinodermata.
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Q56
mcq
Which of the following fungal groups has septate hyphae and reproduces asexually by budding, conidia and fragmentation?
a.
Basidiomycota
b.
Zygomycetes
c.
Chytrids
d.
Glomeromycota
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Q57
mcq
The most commonly used molecular tool for phylogenetic analysis involves sequencing of
a.
mitochondrial DNA
b.
mitochondrial RNA
c.
ribosomal RNA
d.
nuclear DNA
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Q58
mcq
The dynamics of any subpopulation within a metapopulation differs from-that of a normal population in that the
a.
birth rates are lower than the death rates.
b.
death rates are lower than the birth rates.
c.
immigration and emigration rates are significantly higher.
d.
immigration and emigration rates are negligible.
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Q59
mcq
Which of the following is NOT semelparous?
a.
Dracena
b.
Bamboo
c.
Cicada
d.
Mayfly
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Q60
mcq
The general relation between generation time (T) and population growth rate (r) is described by the equation
a.
$\ln r = \ln a - b \ln T$
b.
$r = a - bT$
c.
$\ln r = \ln a + b \ln T$
d.
$r = a + bT$
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Q61
mcq
Which of the following is likely to contribute to the stability of an ecosystem?
a.
High number of specialists
b.
Fewer number of functional links
c.
More omnivores
d.
Linear rather than reticulate food webs
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Q62
mcq
In eusocial insects, males develop from unfertilized eggs while females develop from fertilized eggs. The ultimate consequence of this difference is that
a.
in any colony there are always more males than females. .
b.
a female is genetically more closely related to her sister than to her own offspring.
c.
females are behaviorally more dominant than the males.
d.
in any colony there are always more females than males.
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Q63
mcq
An extraordinary sensory ability that elephants possess is.
a.
emission and detection of ultra high frequency sounds.
b.
emission and detection of ultra low frequency sounds.
c.
detection of changes in earth's magnetic field.
d.
possession of ultraviolet vision.
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Q64
mcq
According to which evolutionary theory, there are long periods without significant -evolutionary changes interrupted by short episodes of rapid evolution?
a.
Punctuated equilibrium
b.
Saltation
c.
Mutation
d.
Neutrality
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Q65
mcq
The mean ($\mu$) and standard deviation ($\sigma$) of body size in a Drosophila population are $8.5$ and $2.2\text{ mm}$, respectively. Under natural selection over many generations the $\mu$ and $\sigma$ of body size change to $8.5$ and $0.8\text{ mm}$, respectively. The type of natural selection responsible for the change is called
a.
directional.
b.
neutral.
c.
disruptive.
d.
stabilizing.
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Q66
mcq
A researcher would like to monitor changes in the level of a serum protein for, which an antibody is available. Which one of the following methods would be best suited for the purpose?
a.
Immunofluorescence microscopy
b.
Fluorescence in situ hybridization
c.
Enzyme linked immunosorbent assay.
d.
Fluorescence activated cell sorting
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Q67
mcq
Which one of the methods listed below is the most sensitive label-free quantification method for proteins
a.
UV spectroscopy
b.
Infra-red spectroscopy
c.
Raman spectroscopy
d.
$^{13}\text{C}$ content of protein
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Q68
mcq
What will happen if wingless RNAi is expressed in wingless expressing cells from the stage when this gene initiates its expression in a developing Drosophila embryo?
A: The enhanced expression of wingless thus caused will broaden the area of *engrailed* expression.
B. Since wingless protein makes a long range gradient, its effect will not be seen in the same segment.
C. The posterior compartment of each future segment will get affected.
D. Since engrailed expression is initiated by pair rule genes, the posterior segment will not be affected.
Which one of the following will most appropriately answer the question?
a.
A and C
b.
Only C
c.
B and D
d.
Only D
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Q69
mcq
A protein has one tryptophan and one, tyrosine in its sequence. Assume molar extinction coefficients at $280\text{ nm}$ of tryptophan and tyrosine as $3000$ and $1500\text{ M}^{-1}\text{cm}^{-1}$, respectively. What would be the molar concentration of that protein if its absorption at $280\text{ nm}$ is $0.90$?
a.
$2\text{ mM}$
b.
$0.4\text{ mM}$
c.
$0.2\text{ mM}$
d.
$0.02\text{ mM}$
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Q70
mcq
Two groups (control, Treated) are to compared to test the effect of a treatment, Since individual variability is high in both groups, the appropriate satistical test to use is
a.
Analysis of variance
b.
Kendall's test
c.
Student's t-test
d.
Mann-Whitney U-test
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Q71
mcq
Sting of a bee causes pain, redness and swelling. Melittin is a major peptide in bee venom. Melittin is a membrane binding peptide that is involved in activating phospholipases in the membrane. The possible target phospholipase that is activated by melittin is
a.
Phospholipase C to generate inositol phosphates.
b.
Phospholipase $\text{A}_2$ to generate arachidonic acid.
c.
Phospholipase D to generate 1', 3'- inositol.
d.
Phospholipase $\text{A}_1$ to generate palmitic acid
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Q72
mcq
The glycolysis and citric acid cycles are important pathways to generate energy in the cell. Given below are statements regarding the production of ATP.
A. Electrons released during the oxidative steps of glycolysis and citric acid cycle produce 10 molecules of $\text{NADH}$ and 2 molecules of, $\text{FADH}_2$ per molecule of glucose.
B. Electrons released during the oxidative steps of glycolysis and citric acid cycle produce 20 molecules of $\text{NADH}$ and 4 molecules of $\text{FADH}_2$ per molecule of glucose.
C. The coenzymes produced are oxidized by electron transfer chain.
D. The conversion of $\text{ADP}$ and $\text{P}_i$ to $\text{ATP}$ takes place in the intermembrane space of mitochondria.
Which one of the following combinations of above statements is correct?
a.
A and B
b.
B and C
c.
C and D
d.
A and C
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Q73
mcq
In a 30-residue peptide, the dihedral angles $\phi, \psi$ have been determined by one or more methods. When their values are examined in the Ramachandran plot, it is
a.
not possible for $\phi, \psi$ values to be distributed in the helical as well as beta sheet region.
b.
possible that the $\phi, \psi$ values are all in the helical region although circular dichroism spectral studies indicate beta sheet conformation.
c.
possible to conclude that the peptide is composed of entirely D-amino acids.
d.
not possible to conclude if the peptide is entirely helical or entirely in beta sheet conformation.
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Q74
mcq
Hydrogen bonds in proteins occur when two electronegative atoms compete for the same hydrogen atom Donor-$\text{H} \dots \text{Acceptor}$.
The angle '$\theta$' between donor and acceptor of a hydrogen bond was determined from large number of X-ray structures of proteins, as shown below:
Which one of the distribution of '$\theta$' was observed from the proteins?
a.
Only b
b.
Only a
c.
Only c
d.
a and b
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Q75
mcq
In the accompanying figure, reaction kinetics of three proteins (a, b, c) is presented. Protein concentrations used to obtain this data are a - 1 mg/ml; b- 4 mg/ml; c - 2 mg/ml.
If catalytic efficiency is defined as $\text{K}_{\text{cat}}/\text{K}_{\text{m}}$, which of the following statements is correct?
a.
$\text{b} > \text{c} > \text{a}$
b.
$\text{a} > \text{b} > \text{c}$
c.
$\text{a} > \text{c} > \text{b}$
d.
$\text{c} > \text{a} > \text{b}$
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Q76
mcq
Lipid rafts are involved in signal transduction in cells. Rafts have composition different from rest of the membrane. Rafts were isolated and found to have cholesterol to sphingolipid ratio fo $2 : 1$. The estimated size of the raft is $35\text{ nm}^2$. If the surface areas of cholesterol is $40\text{ \AA}^2$ and sphingolipid is $60\text{ \AA}^2$. How many cholesterol and sphingolipids are present in one raft?
a.
50 cholesterol : 25 sphingolipid
b.
200 cholesterol : 100 sphingolipid
c.
40 cholesterol : 20 sphingolipid
d.
20 cholesterol : 10 sphingolipid
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Q77
mcq
Glycolipids and sphingomyelin are produced by the addition of sugars or phosphorylcholine to ceramide on cytosolic and luminal surfaces, respectively, of the Golgi apparatus. Finally after such modifications, these molecules are located on the outer half of the plasma membrane. What key events are responsible for such localization?
a.
Membrane fusion only
b.
Action of Flippase and membrane fusion
c.
Action of only Flippase
d.
Flip flop of these molecules in the golgi membrane catalyzed by proton pump
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Q78
mcq
In an attempt to study the transport of secretory vesicles containing insulin along microtubules in cultured pancreatic cells, how would treatment with “colcemid” affect the transport of these vesicles?
a.
Colcemid induces polymerization of microtubules, which in turn would activate vesicular transport.
b.
Polymerization of microtubules is inhibited by colcemid, which in turn would inhibit the transport of secretory vesicles.
c.
Colcemid inhibits the vesicular trafficking through inactivation of v-SNARE protein.
d.
Colcemid activates t-SNARE proteins and in turn activates vesicular transport.
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Q79
mcq
When circular plasmids having a centromere sequence are transformed into yeast cells, they replicate and segregate in each cell division. However, if a linear chromosome is generated by cutting the plasmid, at a single site with a restriction endonuclease, the plasmids are quickly lost from the yeast. It is known that genes on the plasmids are lost because of the instability of the chromosome ends. What could be done so as to restore its stability and can be inherited?
a.
Methylation of adenine residues of the plasmid.
b.
Complexing the plasmid ends with histone proteins.
c.
By incorporating telomere sequences to the end of plasmid.
d.
By incorporating acetylated histone proteins to the plasmid ends.
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Q80
mcq
Rec 8 is a meiosis specific cohesion that maintains centromeric cohesion between sister chromatids in meiosis I. Which of the phenotypes listed below would you predict will be manifested in a rec $8\Delta$ yeast?
a.
Only low viability of dyads.
b.
Improper reduction division and low viability of tetrads.
c.
Improper equational division and low viability of dyads.
d.
Low tetrad viability with no effect on reduction division.
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Q81
mcq
Eukaryotic DNA polymerase $\alpha$ has tightly associated primase activity but moderate processivity. DNA polymerase $\varepsilon$ and $\delta$ are highly processive but lack primase activity. Given below are four statements about leading and lagging strand synthesis in eukaryotes. Which one is true?
a.
Both leading and lagging strands are synthesized by DNA polymerase $\alpha$. Moderate processivity is essential to maintain fidelity of replication.
b.
Entire leading and lagging strands are synthesized by $\delta$ and $\varepsilon$. Eukaryotic replication is primer independent process.
c.
Only the lagging strand synthesis needs primer and synthesized by DNA polymerase $\alpha$.
d.
Primers for both the strands are synthesized by DNA polymerase $\alpha$ followed by “Polymerase switching” with $\varepsilon$ and $\delta$
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Q82
mcq
In context to lac operon, if two bacterial strains P1, and P2 with the genotypes $\text{O}^\text{C}\text{I}^-\text{Z}^-$ and $\text{O}^+\text{IZ}^+$ respectively, were used to produce mero-diploid daughter strain D, which one of the following statements correctly predicts the expression of Z gene ($\beta$ -galactosidase activity) in all the three strains? ($\text{O}+$, $\text{I}^+$ and $\text{Z}^+$ denote the wild type allele of the respective genes).
a.
P1 - No expression; P2 - constitutive expression; D - Inducible expression.
b.
P1 - No expression; P2 - constitutive expression; D - constitutive expression.
c.
P1 - No expression; P2 - Inducible expression; D - Inducible expression.
d.
P1 - Inducible expression; P2 - constitutive expression; D - Inducible expression.
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Q83
mcq
In order to study the transcription factor TFIIH, it was cloned from a large number of human subjects. Surprisingly, the subjects having mutation in TFIIH, also showed defects in their DNA repair system.
Given below are the explanations:
A. DNA damage is always associated with transcription inhibition.
B. TFIIH has no role in DNA repair.
C. In mammalian system, TFIIH plays an active role in transcription coupled. DNA repair process.
D. Because of mutation in TFIIH, transcription initiation is inhibited and incompletely synthesized mRNAs remain attached to the template DNA leading to DNA damage.
Choose the correct answer.
a.
A and B
b.
C only
c.
B and D
d.
D only
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Q84
mcq
The 3'end of most eukaryotic mRNAs is defined by the addition of a polyA tail- a processing reaction called polyadenylation. The addition of poly A tail is carried out by the enzyme Poly(A) Polymerase.
Given below are few statements about this process:
A. Poly(A) Polymerase is a template independent enzyme.
B. Poly(A) Polymerase catalyses the addition of AMP from dATP to the 3' end of mRNA.
C. Poly(A) Polymerase is a RNA-template dependent enzyme
D. Poly(A) Polymerase catalyzes the addition of ADP from ATP to the 3' end of mRNA.
E. Poly (A) Polymerase catalyzes the addition of AMP from ATP to the 3' end of mRNA.
F. Poly (A) Polymerase catalyzes the addition of AMP from dADP to the 3' end of mRNA.
Which of the following combination is true?
a.
B and C
b.
C and D
c.
A and E
d.
C and F
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Q85
mcq
With an intention to identify the -genes expressed in an organism at specific stage of development, mRNAs were isolated from the given organism, cDNAs were synthesized, Cloned in a suitable vector and sequenced. A few of the cDNA sequences showed no matches with the genomic DNA sequence. Further, it was observed that these sequences were U-rich and found to be in stretches dispersed along the sequence. The following may be possible reasons for appearance of such RNA:
A. Splicing
B. Alternate splicing
C. Trans-Splicing
D. Guide RNA mediated introduction of Us involving endonuclease, terminal-U-transferase and RNA ligase
E. Deaminations converting C to U
Which of the following is the most appropriate reasons?
a.
A and C
b.
B and D
c.
C, D and E
d.
D only
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Q86
mcq
When one isolates ribosomes from bacterial lysate, apart from 70S, 50S and 308 ribosomal subunits, one also finds a small population of 100S, 130S and 150S sub-units. EDTA dissociates these larger ribosomal subunits into 50S and 30S, suggesting that they have both the subunits. Upon addition of cations they reassociate into 70S, but none of the other forms could be detected. What is the reason for not obtaining the >70S forms?
a.
The effects of EDTA cannot be reversed by the addition of cations.
b.
190S, 130S and150S are modified form of ribosomes that are irreversibly damaged by EDTA.
c.
100S, 130S etc. represent polysome that cannot be reassembled denovo without other cellular components.
d.
They are obtained as an experimental artifact in-preparations of ribosomes.
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Q87
mcq
Certain chemokines are known to suppress HIV infection whereas proinflammatory cytokines are known to enhance infection. In order to explain these findings, control and chemokine repeptor knock-out animals were treated with pro inflammatory cytokines followed by HIV administration and then infec-tion was assessed periodically. Which one of the graphical representation given below best explain the experimental results.
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q88
mcq
Of the following signaling process, which one is NOT involved in cellular movement or cytoskeletal changes?
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q89
mcq
A researcher was studying a protein “X” which has been observed to move across cells when an extracellular electrical stimulus is provided. An artificial peptide “P” was prepared which resembles the structure of connexins and competitively inhibits connexon formation. Which one of the following statements will best explain the fate of protin ‘X’ if the cells are treated with peptide ‘P’ and then electrical stimulus is provided.
a.
X fails to move across cells due to improper formation of tight junctions.
b.
X fails to move across cells due to improper formation of gap junctions.
c.
X moves freely across cells as before.
d.
X fails to move across cells due to improper formation of desmosomes.
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Q90
mcq
A patient with breast cancer was given a dose of radiation along with chemotherapy and was apparently cured of the tumor. After five years, a tumor was noticed in the patient's lungs, but the doctors confirmed that it was derived from cells of the mammary gland. The following possibilities were suggested by the doctor.
a.
Bacterial infection, after radiation, led to development of the tumors in the lungs.
b.
Migration of residual chemo-resistant cells from the mammary gland resulted in tumors in the lungs.
c.
Epithelial-to-mesenchymal transition had occurred in the lungs.
d.
Cells in the lungs were induced to become a tumor after chemotherapy, and from factors secreted by mammary cells.
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Q91
mcq
Chromatin condensation is driven by protein complexes called condensins which are members of a family of "structural maintenance of chromatin" (SMC) proteins that play a key role in the organization of eukaryotic chromosomes. Condensins along with another family of SMC proteins called cohesins significantly contribute to chromosome segregation during mitosis. If the cells are treated with an inhibitor of cdk1 phosphorylation immediately before the cells enter M phase, which of the following statements is most likely to be true?
a.
Sister chromatids are held together by condensins along the entire length of the chromosome.
b.
Sister chromatids are held together by cohesins along the entire length of the chromosome.
c.
Sister chromatids are held together by condensins and attached to each other only at the centromere.
d.
Sister chromatids are held together by condensins and attached to each other only at the telomere.
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Q92
mcq
There are three substances A, B and C. Given below are the pattern of immunological responses in rabbits when (i) A is administered along with C, (ii) B is administered along with C and (iii) A is conjugated with B and administered along with C.
Which one of the following is the correct identification?
a.
A-protein, B-hapten, C-adjuvant
b.
A-hapten, B-protein, C- adjuvant
c.
A-protein, B- adjuvant, C-hapten
d.
A-hapten, B- adjuvant, C-protein
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Q93
mcq
Following are certain statements regarding seed development in plants:
A. During final phase of development embryo's of "orthodox" seeds became tolerant to desiccation, dehydrate losing up to 90% of water
B. Dormant seeds will germinate upon rehydration while quiescent seeds require additional treatments or signals for the germination
C. Precocious germination is germination of seeds without passing through the normal quiescent and/or dormant stage of development
D. Abscisic acid is known to inhibit precocious germination
Which one of the following combinations is correct?
a.
A, B and C
b.
A, B and D
c.
B, C and D
d.
A, C and D
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Q94
mcq
Development of vulva in C. elegans is initiated by the induction of a small number of cells by short range signals from a single inducing cell. With reference to this, following statements were put forward.
A. When the anchor cell was ablated early in development no vulva formed.
B. In a dominant negative mutant of let-23, a primary vulva formed but the secondary vulva formation did not take place. . C. A cell adopting a primary fate inhibits adjacent cells from adopting the same fate by lateral inhibition involving LIN-39 and also induces the secondary fate in these cells.
D. A constitutive signal from the hypodermis inhibits the development of both the primary and secondary fates but it is overruled by the initial signal from the anchor cell.
Which of the above statements is true?
a.
A and B
b.
A and C
c.
A and D
d.
B and D
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Q95
mcq
Which one of the following about development of sea urchin embryos is TRUE?
a.
Each blastomere of a 4-cell stage possesses a portion of the original animal-vegetal axis and if isolated and allowed to develop will form a complete but smaller size larva.
b.
Each blastomere of a 8-cell stage has the capacity to form a complete embryo but by the 16-cell stage, blastomeres will develop according to their presumptive fate.
c.
Any blastomere isolated till the pluteus larva formation will regulate to go on and develop into a full sized embryo.
d.
After an intricate recombination at the 16 cell stage, the resulting embryo looses its ability to form a complete larva.
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Q96
mcq
What will happen if wingless RNAi is expressed in wingless expressing cells from the stage when this gene initiates its expression in a developing Drosophila embryo ?
(i) The enhanced expression of wingless thus caused will broaden the area of engrailed expression.
(ii) Since wingless protein makes a long rawnge gradient, its effect will not be seen in the same segement.
(iii) The posterior compartment of each future segment will get affected.
(iv) Since engrailed expression is initiated by pair rule genes, the posterior segment will not be affected.
Which one of the following will most appropriately answer the question ?
a.
A and C
b.
Only C
c.
B and D
d.
Only D
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Q97
mcq
Which one of the following is the correct combination?
| Column A | Column B | Column C |
| :--- | :--- | :--- |
| (i) Invagination | (i) Movement of epithelial cells as a unit to enclose deeper layers of the embryo | (i) Hypoblast in birds |
| (ii) Involution | (ii) Splitting of one cellular sheet into two parallel sheets | (ii) Ectoderm in amphibians |
| (iii) Ingression | (iii) Infolding of epithelium | (iii) Mesoderm in amphibians |
| (iv) Delamination | (iv) Migration of individual cells from surface into interior of the embryo | (iv) Endoderm in sea urchin |
| (v) Epiboly | (v) Inward movement of expanding outer layer so that it spreads over the internal surface of remaining external cells | (v) Mesoderm in sea urchin |
a.
A (i), B (iv), C (ii)
b.
A (iv), B (iii), C(i)
c.
A (iii), B (iv), C (v)
d.
A (v), B (ii), C (iii)
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Q98
mcq
Formation of digits and sculpting the tetrapod limb requires death of specific cells in the limb in a programmed manner. Which one of the following interactions could explain proper limb formation?
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q99
mcq
Light is an important factor for plant growth and development. There are several photoreceptors in higher plants such as *Arabidopsis thaliana* involved in perception of various wavelengths of light. Some statements are given below related to photoreceptors:
A. Red light photoreceptors are represented by a gene family.
B. Phytochrome C is the most prominent photoreceptor to perceive red light.
C. Cryptochrome 1 and cryptochrome 2 have evolved from bacterial DNA photolyases.
D. Far-red light is perceived by phytochrome D.
Which one of the following combinations of above statements is correct?
a.
A and B
b.
B and C
c.
C and D
d.
A and C
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Q100
mcq
Pyrurate dehydrogenase is subject to feed back inhibition by its products in glycolysis. Some of the chemical compounds which might be involved in the process, are listed below:
A. NADH
B. FAD
C. Acetyl-CoA
D. Acetaldehyde
Which one of the following combinations of above chemical compounds is involved in feedback inhibition of pyruvate dehydrogenase?
a.
A and B
b.
B and C
c.
C and D
d.
A and C
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Q101
mcq
Carbohydrates synthesized by photosynthesis are converted into sucrose and transported via phloem to other parts of the plant. The following aspects are associated with sucrose uploading in phloem and its transport:
A. Both reducing and non-reducing sugars are transported efficiently through phloem.
B. Sucrose uploading can be both symplastic and apoplastic.
C. The route of phloem uploading is- mesophyll cells $\rightarrow$ phloem parenchyma $\rightarrow$ companion cells $\rightarrow$ sieve tubes.
D. Transport in sieve tubes is as per the 'pressure-flow model'.
Which one of the following combinations is correct?
a.
A, B and C
b.
B, C and D
c.
C, D and A
d.
D, B and A
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Q102
mcq
Symbiotic nitrogen fixation. in legume nodules involves complex interaction between Rhizobium and legume roots. This complex interaction is governed by
A. Integration of *sym* plasmid of *Rhizobium* in the root nuclear genome.
B. Sensing of plant flavonoids by rhizobia.
C. Activation of nod genes in rhizobia.
D. Activation of NODULIN genes in legume roots.
Which one of the following combinations is correct?
a.
A, B and C
b.
A, C and D
c.
B, C and D
d.
A, B and D
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Q103
mcq
A 'Z' scheme describes electron transport in $\text{O}_2$-evolving photosynthetic organisms. The direction of electron flow is presented in the following sequences:
A. $\text{P}680^* \rightarrow \text{Pheophytin} \rightarrow \text{Q}_\text{A} \rightarrow \text{Q}_\text{B} \rightarrow \text{PC} \rightarrow \text{Cytochrome } \text{b}_6\text{f} \rightarrow \text{P}700$
B. $\text{P}700^* \rightarrow \text{Phylloquinone} \rightarrow \text{FeS}_\text{A} \rightarrow \text{FeS}_\text{B} \rightarrow \text{FeS}_\text{x} \rightarrow \text{Fd}$
C. $\text{P}680^* \rightarrow \text{Pheophytin} \rightarrow \text{Q}_\text{A} \rightarrow \text{Q}_\text{B} \rightarrow \text{Cytochrome } \text{b}_6\text{f} \rightarrow \text{PC} \rightarrow \text{P}700$
D. $\text{P}700^* \rightarrow \text{Phylloquinone} \rightarrow \text{FeS}_\text{x} \rightarrow \text{FeS}_\text{A} \rightarrow \text{FeS}_\text{B} \rightarrow \text{Fd}$
Which one of the following combinations is correct?
a.
A and B
b.
B and C
c.
C and D
d.
D and A.
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Q104
mcq
Following are certain statements related to plants exposed to dehydration stress:
A. When the water potential of the rhizosphere decreases due to water deficit, plants continue to absorb water as long as plant water potential is lower than that of soil water.
B. The ratio of root to shoot growth increases in response to water deficit
C. Plant cells tend to release solutes to lower water potential during periods of osmotic stress.
D. Abscisic acid is synthesized at higher rate when leaves are dehydrated, and more ABA accumulates in the leaf apoplast.
Which one of the following combinations of above statements is correct?
a.
A, B and C
b.
B, C and D
c.
A, B and D
d.
A, C and D
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Q105
mcq
A cross was made between $Hfr\ met^+\ arg^+\ leu^+\ str^s$ X $\text{F}^-\ met^-\ arg^-\ leu^-\ str^r$ in which $leu^+$ exconjugants are selected. If the linear organization of the genes are $leu^+\ arg^+\ met^+$, which one of the following genotypes is expected to occur in the lowest frequency?
a.
$leu^+\ arg^-\ met^-$
b.
$leu^+\ arg^+\ met^-$
c.
$leu^+\ arg^+\ met^+$
d.
$leu^+\ arg^-\ met^+$
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Q106
mcq
Two homozygous individuals (P1 and P2), were genotyped using dominant DNA markers A and B, as shown below. The F1 progeny obtained was test crossed and frequency of progeny with which different genotypes appear, is given below:
The following conclusions were made:
A. In the F1, markers A and B are linked and in coupling phase (cis)
B. In the F1, markers A and B are linked and in repulsion phase (trans)
C. The distance between A and B is $10\text{ cM}$
D. The distance between A and B is $5\text{ cM}$
Which of the above conclusions are correct?
a.
A and C
b.
A and D
c.
B and C
d.
B and D
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Q107
mcq
The above pedigree shows the inheritance of a rare allele. The allele is:
a.
X-linked recessive
b.
autosomal recessive
c.
dominant with incomplete penetrance
d.
autosomal recessive with incomplete penetrance
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Q108
mcq
A plant with red fruit is crossed to a plant with white fruit. The F1 progeny had red fruits. On selfing the F1 two kinds of progeny were observed, plants with red fruits and those with white fruits. To test whether it was a case of recessive epistatic interactions a chi-square test was performed. A value of $1.062$ was obtained (chi-square value of $\text{P}_{0.05} = 3.841$ for Degree of freedom = 1). The following statements were made: A. The null hypothesis was that plant with red and white fruits will occur in a $9 : 7$ ratio
B. The null hypothesis was that plant with red and white fruits will occur in a $1 : 1$ ratio
C. Based on the chi square value, it is a case of recessive epistatic interactions
D. Based on the chi square value, it is not a case of recessive epistatic interactions
Which of the combination of above statements is correct?
a.
A and C
b.
A and D
c.
B and C
d.
B and D
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Q109
mcq
Somatic recombination was caused by mild exposure to radiation on flies heterozygous for a given allele during specific stages of development and the individuals were allowed to develop. Such individuals are likely to have
A. clones of homozygous cells in heterozygous body.
B. site specific mutagenesis.
C. twin spots, i.e., patches of mutants cells and homozygous wild type cells in heterozygous body.
D. tissue specific expression of the given allele.
Which of the following combination of answers will be most appropriate?
a.
A and B
b.
B and C
c.
A and C
d.
C and D
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Q110
mcq
Sickle cell anemia is a recessive genetic disease caused due to a point mutation in the $6^{\text{th}}$ codon abolishing one of the $\textit{MspII}$ endonuclease digestion site present in the $\beta$-globin gene. $\textit{MspII}$ digested DNA from a normal person gives two bands, $1150\text{ bp}$ and $200\text{ bp}$, in $\beta$-globin gene. A family with a proband (based on the disease phenotype) gave the following $\textit{MspII}$ digestion pattern:
The following conclusions were drawn:
A. Son (I) is the proband and the given mutation is not present in Son (II).
B. The daughter is a carrier for the given mutation.
C. The gene is X-linked and thus Son (I), becomes the proband.
D. The father and daughter are affected
E. A de novo mutation in same site on normal allele has allowed appearance of diseased phenotype in the proband
Which of the following combination of conclusions wilt be the most appropriate for the figure given above?
a.
A, B and E
b.
A, B and C
c.
B, C and E
d.
C and D
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Q111
mcq
In high altitude, hypoxia induces increased number of circulating red blood cells, which can be explained by the following changes:
A. The transcription factors, HIPs are produced.
B. Erythropoietin secretion is increased
C. Myoglobin content is decreased
D. Cytochrome oxidase is decreased
Which one of following is NOT true?
a.
Only A
b.
A and B
c.
B and C
d.
C and D
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Q112
mcq
The mechanism of sound localization in a horizontal plane by the human auditory system can be explained by
A. the difference in time between the arrival of stimulus in two ears
B. the difference in phase of the sound waves on two ears
C. the difference in tuning curves of two auditory nerves
D. the activity of neurons in superior olivary nucleus, but not by the neuronal activity of auditory cortex
Which one of the following is NOT correct?
a.
Only A
b.
A and B
c.
B and C
d.
C and D
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Q113
mcq
During physical exercise, the oxygen supply to the active muscles is increased which has been explained by the following statements:
A. $\text{P}_{\text{O}_2}$ declines and $\text{P}_{\text{CO}_2}$ rises in the active muscles
B. The temperature is increased and pH is decreased in active muscles
C. 2, 3-biphosphoglycerate is decreased in RBC and $\text{P}_{50}$ rises
D. Metabolites accumulating in the active muscles increase the affinity of hemoglobin to oxygen
Which one of the following is NOT correct?
a.
A only
b.
A and B
c.
B and C
d.
C and D
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Q114
mcq
The fractional clearance of neutral and cationic dextran molecules of various sizes through kidneys of a rat is shown in the figures below.
Which one of the following is correct?
a.
(a)
b.
(b)
c.
(c)
d.
(d)
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Q115
mcq
Estradiol synthesis follows a 2 cell-2-gonadotropin theory, where partial synthesis occurs in the granulosa cells and the rest in the theca interna cells of the Graafian follicle. Which of the following correctly represents estradiol synthesis and secretion?
a.
(a)
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Q116
mcq
Which one of the following is the most appropriate match for the protected areas of India ?
\begin{tabular}{|l|l|}
\hline
\textbf{Category} & \textbf{Protected Area} \\ \hline
A. Biosphere Reserve & (i) Chambal \\ \hline
B. National Park & (ii) Loktak \\ \hline
C. Ramsar site & (iii) Nanda Devi \\ \hline
D. Wildlife Sanctuary & (iv) Rajaji \\ \hline
& (v) Sundarbans \\ \hline
\end{tabular}
a.
A $\rightarrow$ (iii), B $\rightarrow$ (iv), C $\rightarrow$(ii), D$\rightarrow$(i)
b.
A $\rightarrow$ (ii), B$\rightarrow$(iv), C$\rightarrow$(iii), D$\rightarrow$(i)
c.
A $\rightarrow$ (i), B $\rightarrow$ (v), C$\rightarrow$(iii), D$\rightarrow$(i)
d.
A$\rightarrow$ (iii), B $\rightarrow$ (ii), C$\rightarrow$(v), D$\rightarrow$(iv)
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Q117
mcq
The following table shows selected characters used in analyzing the phylogenetic relationships of four plant taxa:
\begin{tabular}{|c|c|c|c|c|}
\hline
\multirow{2}{*}{\textbf{Taxon}} & \multicolumn{4}{c|}{\textbf{Characters}} \\ \cline{2-5}
& \textbf{Xylem or Phloem} & \textbf{Wood} & \textbf{Seed} & \textbf{Flowers} \\ \hline
\textbf{T1} & + & - & - & - \\ \hline
\textbf{T2} & + & + & + & + \\ \hline
\textbf{T3} & + & + & + & - \\ \hline
\textbf{T4} & - & - & - & - \\ \hline
\end{tabular}
Taxa T1, T2, T3 and T4 are respectively:
a.
Ferns, Oaks, Pines, Hornworts
b.
Oaks, Pines, Hornworts, Ferns
c.
Hornworts, Pines, Oaks, Ferns
d.
Ferns, Pines, Oaks, Hornworts
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Q118
mcq
Given below are the characteristics of a few mammalian order. Match the names of the animals with the characteristics of their orders:
A. Hooves with even number of toes on each foot, omnivorous
B. Teeth consisting of many thin tubes cemented together, eats ants and termites
C. Opposable thumbs, forward facing eyes, well developed cerebral cortex, omnivorous.
D. Hooves with an add number of toes on each foot; herbivorous
(i) Tapir
(ii) Lemur
(iii) Aardvark
(iv) Pig
a.
In Lake I zooplankton biomass increases, phytoplankton biomass decreases. In Lake II both phytoplankton and planktivorous fish biomasses increase.
b.
In Lake I zooplankton biomass decreases, phytoplankton biomass increases. In Lake II both phytoplankton and planktivorousfish biomasses increase.
c.
In Lake I planktivorous fish biomass and phytoplankton biomass decrease. In Lake II phytoplankton biomass increases, planktivorous fish biomass decreases.
d.
In Lake I planktivorous fish and zooplankton biomasses increase. In Lake II both phytoplankton and planktivorus fish biomasses increase.
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Q125
mcq
Given below is a matrix of possible interactions beneficial. (+), harmful (-), Neutral (0) between species 1 and (b) The names of interactions, A, B, C and D, respectively; are
a.
Predation, competition, mutualism, commensalism
b.
Mutualism, competition, amensalism, commensalism
c.
Competition, predation, mutualism, amensalism
d.
Competition, mutualism, commensalism, predation
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Q126
mcq
Which of the following is/are NOT valid explanation(s) for the observed pattern of species richness?
A. Older communities are more species rich.
B. Large areas support more species.
C. Natural enemies promote reduced species richness at local level.
D. Communities in climatically similar habitats may themselves be similar in species richness.
E. Greater productivity permits existence of more species.
a.
B, C and D
b.
Only C
c.
Only D
d.
A, B and E
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Q127
mcq
The following table shows the number of individuals of each species found in two communities:
(Hint: In values for 0.05, 0.10, 0.25 and 0.80 are -3.0, - 2.3, -1.4 and -0.2, respectively)
The calculated Shannon diversity index (H) values for communities C1 and C2, respectively are
a.
1.4 and 0.69
b.
1.2 and 0.34
c.
2.1 and 0.43
d.
1.8 and 0.37
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Q128
mcq
In a population at Hardy-Weinberg equilibrium, the genotype frequencies are: $\text{f}(\text{A}_1\text{A}_1) = 0.59$; $\text{f}(\text{A}_1\text{A}_2) = 0.16$; $\text{f}(\text{A}_2\text{A}_2) = 0.25$. What are the frequencies of the two alleles at this locus?
a.
$\text{A}_1 = 0.59\text{ } \text{A}_2 = 41$
b.
$\text{A}_1 = 0.75\text{ } \text{A}_2 = 25$
c.
$\text{A}_1 = 0.67\text{ } \text{A}_2 = 33$
d.
$\text{A}_1 = 0.55\text{ } \text{A}_2 = 44$
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Q133
mcq
In the evolutionary tree given below terms A, B, C, D and E represent respectively
a.
Homo erectus, Homo heidlebergensis, Neanderthal, Denisovan and Homo sapiens.
b.
Homo heidelbergerisis, Homo erectus, Denisovan, Neanderthal and Homo sapiens.
c.
Homo erectus, Homo heidelbergensis, Denisovan, Neanderthal and Homo sapiens.
d.
Homo heidelbergensis, Homo sapiens, Derrisovan, Neanderthal, and Homo erectus.
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Q134
mcq
In transgenic mice, the orientation and location of the loxP sites determine whether Cre recombinase induces a deletion, an inversion or a chromosomal translocation. If a researcher wants to put loxP sites in such a manner that only inversion will take place, which one of the following construct best justifies their intension. Gene X is the target gene.
a.
Gene X followed by two lox P sites pointing towards each other
b.
Gene X flanked by two lox P sites pointing in the same direction (to the right)
c.
Gene X flanked by two lox P sites in inverted orientation (pointing towards each other)
d.
Gene X followed by two lox P sites pointing in the same direction (to the right)
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Q135
mcq
The following genes have been genetically engineered to develop herbicide resistance in plants:
A. Resistance to glyphosate using the 5-enolpyruvyl shikimate-3-phosphate synthase gene
B. Bialaphos resistance using the bar gene
C. Sulfonyl urea resistance using the acetolactate synthase gene
D. Atrazine resistance using the glutathione S-transferase gene .
In which of the above two cases the mechanism is based on abolition of herbicide binding to the enzyme?
a.
A and D
b.
B and C
c.
C and D
d.
A and C
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Q136
mcq
Factor IX is essential for blood clotting. Deficiency of Factor IX could be corrected by delivering factor IX gene using viral vectors. In an experiment the gene for Factor IX was cloned appropriately into Adenovirus (AV), Adenoassociated virus (AAV) and Retrovirus (RV). Retrovirus integrate the gene into the dividing cells. AAV integrates partially into non-dividing cells. AV does not integrate the gene but transfects both dividing and non-dividing cells. Following expression profile for Factor IX was observed when the three vectors were injected intramuscularly into three groups of experimental mice. Which one of the following outcomes is correct?
a.
a by RV; b by AV; c by AAV
b.
a by AV; b by AAV; c by RV
c.
a by AA V; b by RV; c by AV
d.
a by AV; b by RV; c by AAV
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Q137
mcq
Somatic embryogenesis is an important exercise in micropropagation and genetic engineering of plants. The following steps are considered as critical for achieving somatic embryogenesis:
A. Reducing the concentration of sucrose in the medium by half.
B. Addition of the hormone, 2, 4- dichlorophenoxyacetic acid to induce somatic embryos.
C. Reduce agar concentration to 0.6% (w/v)
D. Use maltose in place of sucrose as a carbon source
Which one of the following combinations is correct?
a.
A and C
b.
B and D
c.
A and B
d.
C and D
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Q138
mcq
For the aquaculture farming of Indian major carps several techniques are used. Which one of the following is NOT used for this purpose:
a.
Induced breeding
b.
Selective breeding
c.
Inbreeding
d.
Composite fish farming
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Q139
mcq
A gene from genomic library is screened by using hybridization technique. After hybridizing the probe, usually a stringent washing step is given. The following statements are given to explain the stringent washing step:
A. Stringent washing takes care of removing unincorporated and non-specifically hybridized probe molecules
B. Stringent washing is done in solution having high salt concentration and lower temperature
C. Stringent washing is done in solution having low salt concentration keeping higher temperature
D. Salt present in washing solution supports hybrids to stay intact by shielding the interference of water molecules
E. Salt reacts with DNA molecules and allows easy dissociation of hybrids
F. Stability of hybrid is directly proportional to the temperature
Which combination of the above statements is most appropriate for stringent washing, step?
a.
A, B and D
b.
A, C and D
c.
A, B and F
d.
C, E and F
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Q140
mcq
A student while constructing knock-out mice isolated mouse embryonic, stem cells and introduced an engineered DNA into the cells. However, none of the mice were transgenic. On checking the cells containing DNA construct, he found that he had made a mistake in constructing the DNA since the cells were resistant to gancyclovir but sensitive to G418. Which one of the following constructs had he
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Q141
mcq
In a confirmatory test for HIV, one or more viral antigens are detected in the blood of patients. Following are the steps to be performed for the experiment:
A. Transfer of viral antigens to nitrocellulose paper
B. Incubation with the buffer containing antibodies specific for viral antigens.
C. Separation of viral antigens by SDS-PAGE
D. Detection of bands by enzyme-linked secondary antibody
Identify the correct sequence steps to be performed for the experiment.
a.
A-B-C-D
b.
B-C-D-A
c.
C-A-B-D
d.
C-B-A-D
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