- (d) Plasmids are extra chromosomal, self
replicating usually circular, double stranded
DNA molecules that serve as vectors which carry
foreign DNA segment and replicate inside the
host cell.
- (d) In biocollateral vascular bundle, phloem is
found on both the sides of xylem.
- (c) Cyclosporin A, an immunosuppressive agent
commercially obtained from Trichoderma
polysporum.
- (d) Chemosynthetic bacteria are organisms that
use inorganic molecules as a source of energy and
convert them into organic substances.
- (c)
- (a) When a prokaryote (Bacteria ) is engineered to
express a gene from a plant (Eukaryote), a slightly
different approach is used. Eukaryotes genes
have exons and introns which are transcribed into
primary transcript. It is processed into splicing,
tailing, capping to produce functional mRNA’s.
This functional mRNA is then expressed into
proteins. Prokaryotes lack such machinery
and hence expression of eukaryotic DNA in
prokaryotic cells becomes difficult.
- (c) Plant is taller and diffusion is a slow process
that cannot make the movement of molecules
from root to all parts of the plant.
- (a) Ammonia is first oxidised to nitrite with the
help of the bacteria Nitrosomonas (Nitrococcus).
In the next step nitrite is oxidised to nitrate by the
influence of nitrobacter.
- (c) Abciscic acid is present in chloroplasts and
takes part in degradation of carotenoids.
- (a) Cycas and its relatives are endangered plants,
they are called as reptiles or pandas of plant
kingdom.
- (b) In the legume seed, food is stored in
cotyledons. Legume vegetables have large,
relatively fragile seed. Food reserves are stored
in the pair of cotyledons, sometimes called as the
seed leaves.
- (b) Some characteristic features are developed by
the interaction between two or more genes holding
different distinct locus received from different
parents. Such kind of genes are complementary
to each other, means if it is present alone they
remain unexpressed, but is expressible when they
are brought together with the help of relevant
crossing. These genes are called complementary
genes. For example in Lathyrus odorantus
(sweet pea), both the genes C and P are needed
to incorporate anthocyanin pigment causing a
purple colour. But if any one gene is absent then
anthocyanin will not be produced causing white
flower production.
- (a) Cucumber - Inferior ovary Cotton - Superior
ovary
Guava - Inferior ovary Peach - Half inferior ovary
- (c) Fimbriae are known to help attach the bacteria
to rocks in streams and also to the host tissues.
- (c) Lichens appear as the pioneer organisms on
a bare rock as they can tolerate desiccation and
extreme heating during summers and cooling
during winters. They can also erode the rock and
extract mineral nutrients and survive in extreme
conditions.
- (c) Regulator genes, in Operon concept, are the
genes involved in controlling the expression of
one or more genes. Generally, regulator genes
code for repressor proteins, in prokaryotes.
- (b) 39. (b)
- (a) Streptomycin is an antibiotic used to treat
a number of bacterial infections. Spirulina
represents a biomass of cyanobacteria that can
be consumed as by humans and other animals as
single celled protein,
Rhizobium is symbiotic biofertilizer, Trichoderma
is plant biocontrol agent.
- (a)
- (c) Tropical forest occurs in Assam,Western ghats
and Western himalayas. Major vegetation made
of sal(Shorea robusta), shrubs, grasslands and
desert communities in the region of decreasing
rainfall.
- (d) Barrel shaped endodermal cell have casperian
strip which contain deposition of suberin and
small amount of lignin which makes it water
impermeable.
- (d) Capillarity force is mainly due to the small
diameter of the vessels and tracheids.
- (b) Trait is X-linked recessive, female can be
carrier but male cannot. In the above illustration
‘C’ is a normal unaffected male with XY and ‘D’ is
a female carrier with one affected X chromosome
with genotype XXc.
