- Cleistogamy is advantageous because
(a) hundreds of pollen grains are transferred by each visit
of a pollinator
(b) more efficient and widespread seed dispersal
(c) seed set is not dependent on pollinators
(d) it leads to greater genetic diversity.
- An amniocentesis test on a pregnant woman shows an
extra barr body in the embryo, the syndrome which is likely
to be associated with embryo is
(a) Down’s syndrome (b) Edward’s syndrome
(c) Klinefelter’s syndrome (d) Cri du chat syndrome.
Directions : In the following questions (41-60), a statement of
assertion is followed by a statement of reason. Mark the correct
choice as :
(a) If both assertion and reason are true and reason is the
correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the
correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
- Assertion : Stomata are found on the surface of leaves
in gymnosperms.
Reason : In gymnosperms, cuticle of leaves is thin.
- Assertion: Generally, a woman does not conceive during
the first six weeks of lactation period.
Reason: The hormone ‘prolactin’ initiates and maintains
lactation in a postpartum woman.
- Assertion: Chromosomal aberrations are caused by a
break in the chromosome or its chromatid.
Reason: Duplication, deletion, transversion and
translocations are the result of chromosomal aberrations.
- Assertion: The stem tubers are the swollen ends of
specialised underground stem branches, which help in
vegetative propagation of the plant.
Reason: Solanum tuberosum is an example of a stem
tuber which stores inulin as the main reserve food
material.
- Assertion : The collenchyma is a thick walled living
tissue.
Reason : The collenchyma is thickened due to the
deposition of pectin and cellulose.
- Assertion : “Rosie”, the first transgenic cow, produced
human protein-enriched milk.
Reason : The milk contained the human alpha-(a)
lactalbumin and was more balanced product for human
babies than natural cow milk.
- Assertion : Nitrogen-fixing bacteria in legume root
nodules survive in oxygen-depleted cells of nodules.
Reason : Legheamoglobin completely removes oxygen
from the nodule cells.
48. Assertion : The atmospheric concentration of CO 2 at
which photosynthesis just compensates for respiration is
referred to as CO 2 compensation point.
Reason : The CO 2 compensation point is reached when the
amount of CO 2 uptake is less than that generated through
respiration because the level of CO 2 in the atmosphere is more
than that required for achieving CO 2 compensation point.
49. Assertion : Mitochondria and chloroplasts are semi-
autonomous organelles.
Reason : They are formed by division of pre-existing
organelles as well as contain DNA but lack protein
synthesising machinery.
50. Assertion : A person who has received a cut and is
bleeding needs to be given anti-tetanus injection.
Reason : Anti-tetanus injection provides immunity by
producing antibodies against tetanus.
51. Assertion : Natural selection is the outcome of differences
in survival and reproduction among individuals that show
variation in one or more traits.
Reason : Adaptive forms of a given trait tend to become
more common; less adaptive ones become less common
or disappear.
52. Assertion: Acetylcholine participates in the nerve impulse
transmission across a synapse.
Reason: Acetylcholine is secreted by adrenergic fibres.
53. Assertion : Aschelminthes are called as pseudocoelo-mates.
Reason : In Aschelminthes, mesoderm is present as
scattered pouches in between ectoderm and endoderm.
54. Assertion : Self-incompatibility is a genetic mechanism which
prevents self-pollen (from the same flower or other flowers of
the same plant) from fertilising the ovules by inhibiting pollen
germination or pollen tube growth in the pistil.
Reason : In gametophytic self-incompatibility, the
incompatibility reaction is determined by the genotype of
the sporophytic tissue of the plant from which the pollen
is derived.
55. Assertion : Offsite collections can be used to restock
depleted populations, reintroduce species in the wild and
restore degraded habitats.
Reason : Offsite collections have been successful in
saving black-footed ferret and californian condor from
extinction.
56. Assertion : A population growing in a habitat with
limited resources shows initially a lag phase, followed
by phases of acceleration and deceleration and finally
an asymptote, when the population density reaches the
carrying capacity.
Reason : This type of population growth is called Verhulst-
Pearl Logistic growth, in which a plot of N (population
density) at time (t) results in a sigmoid curve.
