Solved Question paper for NEST Exam

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As per your need i am giving here National Entrance Screening Test questions:

1.1 Choose the correct statement.
(A) According to Carnot, the amount of work was proportional to change in tem-
perature only.
(B) According to Joule, heat could be converted to mechanical work.
(C) According to Carnot, caloric was a form of energy.
(D) According to Clausius, total caloric content of a body was a unchangeable
quantity.

1.2 Choose the correct statement about Lord Kelvin’s universal scale of temperature.
(A) According to Kelvin, efficiency of conversion from heat to mechanical energy
can never be 100% for any temperature of the heat sink.
(B) Increments in temperature on the Kelvin scale were independent of the prop-
erties of water.
(C) Kelvin chose a particular value as zero temperature based on atomic structure.
(D) Mathematical expressions like ideal gas equation hold for Kelvin scale only.

1.3 Arrange the following in chronological order from older to newer.
P: Principle of conservation of energy.
Q: Carnot cycle of heat engines.
R: Celsius scale of temperature.
S: Kelvin scale of temperature.

1.4 Viruses can function as effective agents of evolution because
(A) they prevent occurrence of mutations in the host genome.
(B) they can integrate their genetic material in the host genome.
(C) they are capable of replicating outside a host.
(D) they do not accumulate mutations in a rapid manner.

1.5 Presence of a virus in a host need not necessarily imply manifestation of disease symp-
toms because
(A) the virus may remain dormant in the host.
(B) viral DNA may be rapidly degraded in the host.
(C) the virus may undergo a slow rate of replication.
(D) All of the above.

1.6 Choose the incorrect statement.
(A) Human DNA may contain traces of ancient viruses.
(B) Viruses are dependent on their host for propagation.
(C) Adaptation to drastic changes in climate conditions does not contribute to
genetic modification.
(D) Viruses lose their infective potential permanently once their host develops re-
sistance.

Read the following passage carefully and answer questions 1.1 to 1.3.

James Joule, in his famous experiment of a paddle wheel in water, determined how much
work is required to generate a given amount of heat. His results were taken up byWilliam
Thompson later known as Lord Kelvin, who tried to find appropriate mathematical laws
to express Joule’s experiment. He realised that to formulate them he needed some ab-
solute scale of temperature rather than a scale based on freezing and boiling points of
some convenient liquid. From Carnot’s published work on caloric cycle, Kelvin realised
that the mechanical work done by a perfect frictionless engine depends only on amount
of heat or caloric, and temperatures of heat source and heat sink. For a given temper-
ature of the source, the lower the temperature of the sink, the greater is the amount
of heat converted into mechanical work. However, establishing a universal temperature
scale which is independent of working substance, needed an additional contribution from
Rudolf Clausius. Clausius showed that Carnot’s ‘caloric’ was indeed the same as Joule’s
‘Heat’. Clausius’ work meant that Carnot was mistaken when he thought of an engine
doing work solely because its caloric dropped in temperature. Clausius reasoned that
caloric could not be destroyed but claimed it could be converted into something else; in
an engine, for example, it was converted into mechanical work.
With Clausius’ work, Kelvin now had the clue he needed. He realised that in experi-
ments with heat sinks and sources, what the heat sink does not absorb is converted into
mechanical work. Thus, if the sink is at ‘zero-temperature’ and remains so, it is taking
no heat from the working substance. All energy is therefore available for conversion to
mechanical work. For convenience, Kelvin took his increment of 1◦ to be the same as the
Celsius scale and deduced that his ‘absolute zero’ was at -273.1◦C. This absolute zero
point on Kelvin’s scale is, in fact, not attainable due to the way atoms are governed,
though Kelvin did not know about this. The work of Clausius and Kelvin made it clear
that heat was no mysterious weightless fluid but was a form of energy. So, too, was
mechanical work. This gave deeper meaning to the principle of conservation of energy
already stated by Hermann von Helmholtz in 1847.

1.1 Choose the correct statement.
(A) According to Carnot, the amount of work was proportional to change in tem-
perature only.

(B) According to Joule, heat could be converted to mechanical work.
(C) According to Carnot, caloric was a form of energy.
(D) According to Clausius, total caloric content of a body was a unchangeable
quantity.
1.2 Choose the correct statement about Lord Kelvin’s universal scale of temperature.
(A) According to Kelvin, efficiency of conversion from heat to mechanical energy
can never be 100% for any temperature of the heat sink.
(B) Increments in temperature on the Kelvin scale were independent of the prop-
erties of water.
(C) Kelvin chose a particular value as zero temperature based on atomic structure.
(D) Mathematical expressions like ideal gas equation hold for Kelvin scale only.
1.3 Arrange the following in chronological order from older to newer.
P: Principle of conservation of energy.
Q: Carnot cycle of heat engines.
R: Celsius scale of temperature.
S: Kelvin scale of temperature.
(A) R - Q - P - S. (B) R - Q - S - P.
(C) P - Q - R - S. (D) S - R - Q - P.
Read the following passage carefully and answer questions 1.4 to 1.6.
If a population of individuals has to survive, reproduce and expand, it must con-
stantly interact and adapt with its co-existing players in the same environment.
Food, climate, predators as well as host-pathogen relationships collectively play a
significant role in evolution. Pathogenic viruses are capable of infecting a wide range
of organisms ranging from bacteria to humans. Many viruses integrate their genome
in their host DNA and are capable of existing within the host cell in a dormant state.
The inheritable presence of viral genome(s) within the host DNA has the potential
to influence evolution of the host genome. Also, a large population of rapidly multi-
plying viruses makes them amenable to accumulation of higher amounts of genetic
variation or mutation. This potential is used by viruses to undergo rapid adaptation
and evolution to overcome host defense mechanisms and to broaden their host range.
Viruses, such as the HIV-1, may be one of such biological entities that researchers
can actually witness come into being, providing a real-time example of evolution in
action.

1.4 Viruses can function as effective agents of evolution because
(A) they prevent occurrence of mutations in the host genome.

(B) they can integrate their genetic material in the host genome.
(C) they are capable of replicating outside a host.
(D) they do not accumulate mutations in a rapid manner.
1.5 Presence of a virus in a host need not necessarily imply manifestation of disease symp-
toms because
(A) the virus may remain dormant in the host.
(B) viral DNA may be rapidly degraded in the host.
(C) the virus may undergo a slow rate of replication.
(D) All of the above.
1.6 Choose the incorrect statement.
(A) Human DNA may contain traces of ancient viruses.
(B) Viruses are dependent on their host for propagation.
(C) Adaptation to drastic changes in climate conditions does not contribute to
genetic modification.
(D) Viruses lose their infective potential permanently once their host develops re-
sistance.
1.7 The distance vs. time graph on the
right shows motion of two buses (A
and B) between towns P and Q. Bus
A goes from P to Q and bus B goes
from Q to P. Which of the follow-
ing statements is supported by the
graph.
(A) Both the buses leave respective towns simultaneously.
(B) Excluding halting times, both the buses travel with the same average speed.
(C) Distances in the problem are referred to from town Q.
(D) Both buses take halts at the same locations during the journey.
1.8 Which of the following numbers is divisible by 5?
(A) 250 + 1 (B) 250 + 2 (C) 250 + 3 (D) 250 + 4

1.9 Which of the following type of eclipses will be visible from the Moon?
(A) Total eclipse of the Earth. (B) Partial eclipse of the Earth.
(C) Total eclipse of the Sun. (D) Annular eclipse of the Sun.
1.10 A classic example of natural selection is the change in relative populations of the
peppered moth that occurred during the industrial revolution in England. After the
industrial revolution in 1870s, booming industrial cities started releasing tons of black
soot, blackening tree trunks and rocks and creating an environment where moths with
light colours were easily predated by birds. Peppered moths captured in 1850 and 1900
reveal that two industrial cities (X and Y) had the following percent distributions.
Year 1850 1900
Moths Light coloured Dark coloured Light coloured Dark coloured
X 66 34 22 78
Y 65 35 27 73
Pollution control rules were introduced in 1902 and were properly followed in city Y, but
not in city X. If all other factors remain constant, then what could be the approximate
expected distribution of light and dark coloured moths in 1950?
(A) Light X = 8, Y = 28 and Dark X = 92, Y = 72
(B) Light X = 8, Y = 62 and Dark X = 92, Y = 38
(C) Light X = 18, Y = 23 and Dark X = 82, Y = 77
(D) Light X = 18, Y = 50 and Dark X = 82, Y = 50
1.11 An electronics store conducted a survey by asking every fourth person entering their
store if they already owned a television set. On a given day out of 100 total respondents,
80 answered the question in the affirmative. Next day the same survey was conducted
by choosing every fifth person entering the store and the number of respondents was
again 100. Which of the following is the most likely number of respondents answering
in the affirmative?
(A) 64 (B) 78 (C) 100 (D) 92
1.12 Choose the correct statement.
(A) Detergents are sodium salts of carboxylic acids.
(B) Soaps are sodium salts of sulfonic acids.
(C) Detergents form precipitate with calcium and magnesium ions.
(D) Soaps are generally biodegradable.
For rest of the questions in this section, each correct answer will earn 2 marks.

1.13 Which of the following date has been declared as “National Mathematics Day”?
(A) 28 February. (B) 22 June.
(C) 23 September. (D) 22 December.
1.14 Which of the following wildlife sanctuaries is not involved in “Project Tiger”?
(A) Corbett. (B) Gir. (C) Kanha. (D) Bandipur.
1.15 Who is known as father of ‘white revolution’?
(A) Verghese Kurien. (B) Sundar Lal Bahuguna.
(C) M. S. Swaminathan. (D) Birbal Sahni.
1.16 Which of the following is a primary source of gelatin used in ice-cream?
(A) Jellyfish. (B) Marine algae.
(C) Fruit skin. (D) Animal bones.
1.17 Hand-held GPS units in modern phones identify your location by
(A) transmitting their location and time to GPS satellites.
(B) receiving location data of GPS satellites.
(C) receiving time data from GPS satellites.
(D) exchanging location and time data with GPS satellites.
1.18 Which of the following is a strong smelling agent that is added to LPG to detect gas
leakage?
(A) Ethanethiol. (B) Dimethyl sulfide.
(C) Dimethyl sulfone. (D) Hydrogen sulfide.
1.19 What is the principle behind the light emission by a firefly?
(A) Chemiluminescence. (B) Fluorescence.
(C) Phosphorescence. (D) Electroluminescence.

Section 2: BIOLOGY
Marks for Section 2: 50
This section contains 14 questions.
For questions 2.1 to 2.10 only one of the 4 options is correct. A correct answer will
earn 3 marks, a wrong answer will earn (−1) mark, and an unattempted question will earn
0 marks.
2.1 Which one of the following occurs during osmosis?
(A) The movement of water from a concentrated solution to a dilute solution across
a semi-permeable membrane.
(B) The movement of a dissolved substance from a concentrated solution to a dilute
solution across a semi-permeable membrane.
(C) The movement of water from a dilute solution to a concentrated solution across
a semi-permeable membrane.
(D) The movement of a solute from a dilute solution across a semi-permeable mem-
brane.
2.2 The umbilical artery carries blood from the fetus to the placenta and the umbilical vein
carries blood from the placenta to the fetus. Which is the correct statement regarding
differences in blood composition between the umbilical artery and vein?
(A) Blood in the umbilical artery contains less glucose than blood in the umbilical
vein.
(B) Blood in the umbilical artery contains less carbon dioxide than blood in the
umbilical vein.
(C) Blood in the umbilical artery contains more deoxygenated than blood in the
umbilical vein.
(D) Blood in the umbilical artery contains less urea than blood in the umbilical
vein.
2.3 Antibiotics are routinely used for controlling bacterial infections, but are ineffective
against most viral infections. Why?
(A) Viruses are too small to be affected by antibiotics.
(B) Viruses have mechanisms to block the action of antibiotics.
(C) Antibiotics stimulate the immune system against bacteria but not viruses.
(D) Viruses do not have an independent metabolism.
Page 8
2.4 Programmed cell death (PCD) is a tightly regulated process that is important in the
growth and development of plants. In plants there are several tissues which become func-
tional after undergoing PCD. Which of the following cells/tissues represent “functional
corpses” arising due to PCD in plants?
(i) Cork cells in bark.
(ii) Sieve elements of phloem.
(iii) Companion cells of phloem.
(iv) Tracheary elements of xylem.
(A) (i) and (ii) only. (B) (ii), (iii) and (iv) only.
(C) (i) only. (D) (i) and (iv) only.
2.5 With reference to the nervous system, pick the correct statement from the options given
below.
(A) A ganglion is a collection of cell bodies.
(B) A ganglion is a collection of axons.
(C) A nerve is a collection of cell bodies.
(D) A nerve is a collection of dendrites.
2.6 Unlike animal cells, plant cells are characterised by the presence of a large central
vacuole. The central vacuole performs a variety of functions during plant growth and
development. One of these functions is similar to that performed by lysosomes in animal
cells. Which of the following represent functions of vacuoles in plants?
(i) Storage of water and salts.
(ii) Cell expansion.
(iii) Storage of metabolic waste products.
(iv) Degradation.
(A) (i) and (ii) only. (B) (i), (iii) and (iv) only.
(C) (i), (ii), (iii) and (iv). (D) (i), (ii) and (iii) only.
2.7 A short peptide has a sequence of amino acids valine-serine-methionine-proline, and the
t-RNAs used in its synthesis have the following corresponding anticodons:
3’-CAG-5’, 3’-UCG-5’, 3’-UAC-5’, 3’-UUU-5’. What is the sequence of DNA that en-
codes the peptide?
(A) 5’ GACGCTCATTTT 3’ (B) 5’ UUUCAUGCUGAC 3’
(C) 5’ CAGTCGTACTTT 3’ (D) 5’ TTTCATGCTGAC 3’
Page 9
2.8 Any population comprises of three categories of individuals based on their ages: (i) pre-
reproductive (ii) reproductive and (iii) post-reproductive individuals. A certain popula-
tion has the following numbers of individuals in each category:
Reproductive individuals : 3.0 million
Post-reproductive individuals : 0.5 million
Pre-reproductive individuals : 4.3 million
Such a population would be termed as
(A) expanding. (B) declining. (C) stable. (D) aging.
2.9 Two different DNA samples were isolated from biological specimens. Further experi-
ments demonstrated that one of these (X) was composed of 30% A, 30% G, 20% T and
20% C but could not be cut by an exonuclease (an enzyme that cuts nucleotides from
the ends of DNA). The second DNA sample (Y) could be cut by the exonuclease and
was found to be composed of 30% A, 30% T, 20% G and 20% C. Which of the following
statements can be correctly deduced from the above?
(A) DNA X has a double-stranded, linear structure.
(B) DNA X has a single-stranded, circular structure.
(C) DNA Y has a double-stranded, circular structure.
(D) DNA Y has a single-stranded, linear structure.
2.10 Increased application of pesticides and insecticides has been shown to increase the
occurrence of resistant varieties of pests and pathogens. What could be the probable
reasons for the rapid evolution of resistant varieties of insects?
(i) Mutations in the existing population of insects/pests.
(ii) Preferential multiplication of resistant individuals.
(iii) Rapid degradation of the insecticide/pesticide.
(iv) Migration of insects/pests away from the sprayed areas.
(A) (iii) and (iv) only. (B) (i) and (ii) only.
(C) (i) and (iii) only. (D) (ii) and (iv) only.
For questions 2.11 to 2.14 one or more than one of the 4 options may be correct. Your
answer is regarded correct only if you choose all the correct option(s) and no incor-
rect option(s). A correct answer will earn 5 marks, a wrong answer or an unattempted
question will earn 0 marks.
2.11 Neurons were kept in a physiological solution. During the resting phase, the membrane
potential in the axoplasm of neurons was negative compared to the extracellular space
and a potential difference of -70 mV was observed in this phase. Neurons were then

treated in two different experiments with either gamma-amino butyric acid (GABA;
an inhibitory neurotransmitter) or glutamate (an excitatory neurotransmitter) and the
membrane potentials were recorded. Choose the correct statement/s:
(A) The resting membrane potential of -70 mV would not change with either
GABA or glutamate treatments.
(B) The membrane potential would be even more negative than resting phase with
GABA treatment.
(C) The membrane potential would be positive when the neuron was exposed to
glutamate.
(D) The membrane potential would be more negative than resting potential after
glutamate treatment.
2.12 Agrobacterium-mediated transformation is routinely used for the development of trans-
genic plants. In these experiments, a suitable plant part (explant) is incubated with
Agrobacterium cells containing the gene of interest (passenger gene) that is to be intro-
duced into the plant. In addition, a selectable marker gene is also used to ensure growth
of only the transformed cells on regeneration media containing the selection agent (for
e.g., antibiotics such as Kanamycin or Hygromycin). Based on such strategies, six in-
dependent transformation experiments of tobacco leaf explants were carried out using
two different constructs - (1) construct I containing only a Hygromycin-resistance gene
(HY GR) as a selection marker and (2) construct II with the HY GR gene as a selection
marker and a passenger gene encoding a dephosphorylase enzyme (DEP) that inhibits
phosphorylation in cells in which it is expressed. The marker as well as passenger genes
were placed under transcriptional control of a constitutive promoter (CaMV35S), which
expresses in all cells/tissues. The results obtained are tabulated below.
Construct I Construct II
(CaMV35S- HY GR) (CaMV35S-DEP + CaMV35S-HY GR)
Expt. No. of explants No. of transgenic No. of explants No. of transgenic
No. used plants obtained used plants obtained
1 200 45 200 0
2 200 40 200 0
3 200 48 200 0
Which of the following statements could represent probable explanations of the above
results?
(A) Regeneration medium for use of the selection marker in construct II was not
optimised.
(B) Expression of the DEP gene is lethal to the transformed cells.
(C) Degradation of Hygromycin occurred in experiments with construct II.
(D) The HY GR gene used in construct II lost its functionality probably due to
mutation(s) either in the gene or in the promoter.

2.13 Secretin and cholecystokinin (CCK) are
two hormones acting on the pancreas. While
hydrochloric acid (HCl) from the stomach
predominantly stimulates release of secretin,
peptones are potent stimulators of CCK se-
cretion. Fatty acids however, stimulate re-
lease of both secretin as well as CCK. Se-
cretin results in pancreatic secretion of bi-
carbonate ions which helps to set the pH for
optimal functioning of pancreatic digestive
enzymes. CCK stimulates secretion of pan-
creatic digestive enzymes. A graphical rep-
resentation of the effects of HCl, fatty acids
and peptones on the pancreas is shown be-
low. Based on the this data , which of the
following statement/s is/are correct?
(A) HCl would be required for optimal digestion of peptones.
(B) Compared to HCl and fatty acids, peptones are less effective in stimulating
release of secretin.
(C) Compared to HCl, fatty acids are less potent stimulators of sodium bicarbonate
secretion.
(D) HCl and peptone are equally potent stimulators of digestive enzymes.

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