AHSEC| CLASS 12| BIOLOGY| SOLVED PAPER - 2023| H.S. 2ND YEAR
2023
BIOLOGY
(Theory)
Full Marks: 70
Pass Marks: 21
Time: Three hours
The figures in the margin indicate
full marks for the questions
PART-I
(BOTANY)
MARKS
- 35
PART-II
(ZOOLOGY)
MARKS
- 35
Part - I (Botany)
1. Name the enzyme which help in unwind of the DNA helix. 1
Ans:- helicases.
2. Where is occurred coleoptile? 1
Ans:- In
grass plants.
3. What is cellular totipotency? 1
Ans:- Cellular
totipotency is the inherent ability of a plant cell to give rise to an entire
plant, an ability that is retained even after a single cell has undergone final
differentiation in the plant body.
4. What is meant by speciation? 1
Ans:- Speciation
is defined as the evolutionary formation of new biological species, usually by
splitting the same species into two or more genetically distinct species.
Speciation occurs with the help of genetic drift, migration, geographical
isolation and natural selection.
5. What do you mean by Biofertilizer? 2
Ans:- Biofertilizers
are biological preparations of efficient microorganisms that promote plant
growth by improving the acquisition of nutrients. They increase soil
productivity by fixing atmospheric nitrogen, solubilizing phosphorus in the
soil, and stimulating plant growth.
6. Name the microbes used for production
of curd and vinegar. 1+1=2
Ans:- Lactobacillus
bacteria are helpful in making curd.
Acetic acid bacteria in vinegar.
7. How DNA isolated in purified from a
bacterial cell? 2
Ans:- DNA is
genetic material that is isolated in pure form by treating bacterial cells with
enzymes such as lysozyme to remove the cell wall.
Or
What is recombinant DNA? List the tools of genetic engineering. 2
Ans:- Recombinant DNA, often abbreviated
as rDNA, is an artificially created DNA strand that is formed by combining two
or more gene sequences. This new combination may or may not occur naturally,
but it has been specifically engineered for the purpose of being used in one of
the many applications of recombinant DNA.
(i) Restriction enzymes: Restriction
enzymes, also known as restriction endonucleases, are proteins produced by
bacteria that cut DNA at specific locations.
(ii) DNA ligase: DNA ligase is an enzyme
that facilitates joining of DNA strands together by forming phosphodiester
bonds.
(iii) Plasmids: Plasmids are small,
circular pieces of DNA that are separate from the chromosomal DNA found in
cells.
(iv) Gene guns: Gene guns are physical
devices used to deliver DNA directly into cells.
(v) CRISPR-Cas9: CRISPR-Cas9 is a
revolutionary genetic engineering tool that provides a more precise and
efficient way to edit DNA.
(vi) Electroporation: Electroporation is
a method used to introduce foreign DNA into cells.
8. Write briefly about application of
electrophoresis. 2
Ans:- One of
the most important applications of electrophoresis is DNA analysis and study of
DNA fragments. DNA (or deoxyribonucleic acid), known for the stability of its
negative charge, is affected by the presence of electric current.
Or
Write brief account on ethical issues on biotechnology. 2
Ans:- Ethical issues in biotechnology
are specific issues that are morally wrong. Such issues may affect fundamental
moral principle which conflicts with the normal functioning of the society at
large. We have divided the ethical issues related to biotechnology into
specific subcategories. These groups are-
There are many principles related to ethics, medical ethics,
scientific and technological ethics, justice and human dignity and its related
ethics and many such ethical issues in biotechnology.
(i) Socio-economic issues: The
scientific community and society promise significant advances in biotechnology,
but never promise harmlessness with respect to socio-economic life.
(ii) Cultural issues: Different cultures
have different ideas and values. These values are a reflection of his long-term
vision. Sometimes biotechnology interferes with these cultural concepts.
9. Write the applications of mycorrhizae.
2
Ans:- Mycorrhizal
fungi associated with plant roots increase the absorption of nutrients,
especially phosphorus, and thus enhance the growth of crop plants and trees.
The
level of mycorrhizal inoculum in the soil and their colonization in the roots
of various forest plants, thereby reducing fertilizers, pathogen effects and
fungicides and protecting the topsoil, soil erosion and water-logging.
10. Explain briefly: (any two) 2+2=4
(i) Cry protein
Ans:- Cry protein is a crystal protein
that is toxic to insects and is expressed by the cry gene. Bacillus
thuringiensis bacteria produce it in an inactive form. The alkaline pH in
insects helps activate Rho proteins when they consume them.
(ii) Transgenesis
Ans:- Transgenesis can be defined as the
uncontrolled transfer of foreign DNA into the germline of an animal species.
Transgenesis became possible only after significant advances were made in the
understanding of the developmental, reproductive, and molecular biological
principles of the mammalian genome.
(iv) Bioreactor
Ans:- Bioreactors are vessels or tanks
in which whole cells or cell-free enzymes convert raw materials into
biochemical products and/or less undesirable by-products. The microbial cell
itself is a miniature bioreactor; Other examples include shake flasks, petri
dishes, and industrial fermenters.
11. Write the scientific name with their
utility of the following plants: (1/2+1/2)x3=3
(i) Sarpagandha
Ans:- Rauvolfia serpentina is known for
its medicinal importance. It is one of the best remedies that is widely used
for high blood pressure and as a sedative and tranquilizing agent.
(ii) Beladona
Ans:- Belladonna, also known as Atropa
belladonna or deadly nightshade, is a perennial herb in the nightshade family
Solanaceae. Its roots, leaves and fruits contain hyoscyamine, scopolamine and
mostly atropine. These alkaloids are naturally occurring muscarinic
antagonists.
(iii) Arjun
Ans:- Terminalia arjuna, commonly known
as arjuna, belongs to the Combretaceae family. Based on the observations of
ancient physicians, decoctions of its bark have been used for centuries in the
Indian subcontinent for chest pain, hypertension, congestive heart failure, and
dyslipidemia.
(iv) Teak
Ans:- One such interesting plant is
Tectona grandis L.f. (TG). It belongs to the Verbenaceae family. It is commonly
called teak. It is a large deciduous tree and can reach a height of 30–40
meters with flutes and buttresses found at the base of older trees.
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