stranded DNA. This viral DNA is then integrated/
incorporated into the T-lymphocyte's DNA/genome
(as a provirus) by integrase in a latent. HIV is in this
latent, non-virulent form during the period of clinical
latency.
(ii) Replication of HIV destroys T-lymphocytes resulting in
low T-lymphocytes count.
As a result the immune system weakens, resulting
in AIDS. Increasing susceptibility to opportunistic
infections results in mortality in 11th year.
(iii) HIV protease is the enzyme inhibited by alpha
interferon.
As a result of its inhibition, HIV polyprotein cannot be
cleaved into individual functional proteins like capsid
proteins, reverse transcriptase and integrase.
Hence, virus remains immature, non-infectious and
non-functional and is unable to infect other cells to
carry out further infection.
- (i) Antigen protein would be expressed in rice cells,
and would trigger the immune system to produce the
antibody against it, with a specific configuration that
is complementary to the glycoprotein (antigen).
This antibody will help to mount an immune response
against infection by cholera bacteria, thereby
generating secondary immune response.
(ii) Callus is necessary for growing genetically modified
rice due to the following reasons:
(a) Callus divides by mitosis to ensure all the genetically
identical daughter cells would have the gene.
(b) Callus can be genetically modified by A. tumefaciens
and can be sub-cultured to increase the number of
callus. Also, callus can be manipulated by auxin and
cytokinin to induce root and shoot formation to form
plantlets.
(iii) Rice can be stored for a long time. It also forms a
staple diet among many Asians, and so can reach a
larger target population.Besides that, rice is versatile
enough to be eaten with other dishes.
4.(i) Hemagglutinin facilitates attachment of virus to
host cell membrane by binding to specific sialic acid
receptors on epithelial cells. Neuraminidase facilitates
the release of newly formed virus from the infected
host cell by cleaving the sialic acid receptors.
(ii) Host RNA polymerase is a DNA-dependent RNA
polymerase, while the virus RNA polymerase is a RNA-
dependent RNA polymerase.
5.(i) Cell surface membrane (CSM) of cell is made up
of lipid bilayer with hydrophobic core made up of
hydrocarbon tail of fatty acid. Oxytocin is a peptide
hormone which is hydrophilic. It is unable to transverse
lipid bilayer because of absence of transmembrane
transport protein for oxytocin.
(ii) Oxytocin binds to G-protein coupled receptor (GPCR)
(at extracellular face), which has an associated inactive
G-protein and results in change in conformation
of GPCR. It stimulates GDP exchange for GTP as
a-subunit of G-protein and is translocated along
cytoplasmic face of CSM towards effector.
Phospholipase cleaves many phosphatidylinositol
4, 5-biphosphate (PIP 2 ) molecules into second
messengers like diacylglycerol (DAG) and inositol-1,
4, 5-triphospate (IP 3 ) during signal amplification at
this stage. DAG activates protein kinase C which
carries out target cellular responses. IP 3 stimulates
the release of Ca2+ ions from ER; Ca2+ forms complex
with calmodulin, which carries out target cellular
responses.
nnS
cience Olympiad Foundation is a Delhi based organisation
established by leading academicians and scientists with
the aim of popularizing Science, Mathematics, Computer
Education and English and to promote scientific attitude through
innovative and creative activities involving school students across
the globe.
Towards this objective, SOF wants to create support material such
as books, workbooks and other resources which will support the
mission of creating passion for the science and maths subject
amongst students globally.Inviting Innovative Teachers, Content Developers,
Translators (English to Hindi),
Authors in science, Maths, English & G.K.
[email protected]If you have the passion to create world class innovative resource
(books etc.) that will be followed by students in India and abroad
then SOF is willing to support you in unlocking the potential.
We are looking for teachers with an innovative bent of mind,
educationists and subject matter experts who will work as a
team to create these resource materials. Experience of 4-5 years
in Physics, Chemistry, Mathematics, Biology, English and General
Knowledge at class 2-12 level, excellent writing skills, high levels
of creativity and a keen passion to reach out to students is a must.
If this excites you please write to us at: