SAMPLE QUESTION PAPER (2021-22)
BIOLOGY (044)
TERM II
CLASS 12
Time: 2 Hrs Max. Marks: 40
GENERAL INSTRUCTIONS
i. All questions are compulsory.
ii. The question paper has three sections and 13 questions. All questions are compulsory.
iii. Mark distribution:
a. Section–A has 6 questions of 2 marks each
b. Section–B has 6 questions of 3 marks each
c. Section–C has a case-based question of 5 marks.
iv. There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
v. Wherever necessary, neat and properly labelled diagrams should be drawn.
SECTION A
Attempt all questions: –
Q.1 Why the disease Filariasis also called as Elephantiasis? What is the reason of the commonly observable symptom?
The appearance of leg (elephant leg like)
Blockage of lymph vessel, fluid oozes out in tissues, oedema and swelling.
Q.2. The after effect of urbanization has been to ignore our resource rich villages. The increase in human population and metronization have its own issues of resource utilization. At the end of the day, a lot of environmental issues crop up. How the figure given below help to sort out the problem?
To utilize the village resources (cow dung) for biogas production.
To reduce health issues during cooking of food.
OR
What is competition exclusion principle? Explain it with an example.
Competition exclusion: Scotland-inter tidal rocky zone: larger barnacle competing with smaller barnacle and thereby over powering and eliminating the latter.
Q.3. What is a fermentor? The alcoholic end products are basically produced by two different processes. What is the basic difference between them?
A large container used to culture the microbes for the industrial production of
useful bio molecules.
a. Process with distillation: Alcohol synthesis
b. Process without distillation: Bear, wine
Q.4. Two physical factors are the main contributors in deciding the type of biome. Based on it, how a desert differs from a grassland?
Two physical factors: temperature and moisture.
Desert:- Temperature range: Average 50C to 250C / Moisture – <50 cm
Grass land:- Temperature range: Average 100C to 250C / Moisture: 50 – 250 cm
Q.5. An ecologist studied a forest with deer population. His study was based on food chains existing. Top carnivore in the said forest was cheetah. How will the presence of cheetah affect the population of deer? In case the top carnivore is eliminated from the scene, how will it affect the ecological balance?
Deer in the presence of top carnivore (Cheetah): Population under control: (S-shaped curve)
Deer in the absence of top carnivore (Cheetah): Population uncontrolled: (J-shaped curve)
Q.6. What are sticky ends? What is there significance in reference to DNA technology?
Sticky ends: the opened cut palindrome sites of the DNA duplex having complimentary base pairs on the opposite chains. It is used to insert gene of interest during r-DNA technology.
OR
Explain the procedure by which PCR helps in early detection of cancer?
PCR: Denaturation, Annealing, Extension.
It helps to identify the mutated portion of gene, mutation may act as a causative factor for cancer initiation.
SECTION B
Q.7. The chemicals that are considered the ultimate warfare inside the body are very specific.
a. What is this chemical called?
Antibodies.
b. Explain its structure which makes it possible to execute its function.
Structure depicting: Y-shape, H2L2, S-inter molecular linking, antigen binding sites.
OR
How does MALT help us as defense system? What role does lymph nodes play in defense system?
MALT: Mucosal Associated Lymphoid Tissue: Forms defense in all moist, internal mucosa layers. Lymph nodes provide opportunity for the lymphocytes to interact with the antigen and then mature and diversify.
Q.8. Explain the two basic approaches for conservation of threatened species?
Details of In-Situ and Ex-Situ approaches with example.
Q. 9. What is a cloning vector? What is essential for a vector to function normally?
Cloning vector: A plasmid (extra chromosomal DNA) with specific property of replication and carrying the gene of interest.
Essential property: ORI site, recognition site, antibiotic resistance gene,
Q.10 The organisms belonging to an ecosystem generally follow one of the two approaches with regards to physical factors to successfully thrive in the said ecosystem. Explain this with proper example.
Regulators and Conformers.
Explain the concept with examples
Q.11 How the narrow and broad utilitarianism help us to better manage and conserve the biodiversity?
Narrow utilitarian approach: Immediate use/profit (wood, medicine, fiber, fruit etc)
Broad utilitarian approach: Not of immediate use (O2, CO2, aesthetics etc)
Q.12 Explain the process of obtaining the foreign gene product?
Obtaining foreign gene product: Bioreactor / Fermentor are used to culture the GMO’s. After the requisite time, the products are ready and needs to be separated. The material undergoes a series of steps to increase the concentration. Finally it undergoes purification of the product.
SECTION C
Q.13 Because of the perceived benefits, drugs are oftenly used repeatedly. The most important thing which one fails to realize is the inherent addictive nature of the drugs and the alcohol. Addiction is basically a psychological attachment to certain effects of the drugs. The effects like euphoria or a temporary feeling of wellness becomes a driving force for people to reuse it. With each dose, the specific effect that a person experiences is less, so there develops a need to increase the dose to reach the same height as that during first exposure. This is because the tolerance level of the receptors increases so receptors require increased dose to
produce stimulation. Many social factors also contribute towards first and then the repeated exposures. Finally, a stage comes where a person feels like trapped in a vicious cycle of addiction and withdrawal symptoms. Such cases may be difficult to manage at parental level and therefore needs medical intervention. Sadly a major chunk of such cases are adolescents and that too in cities.
a. What is drug dependence?
Drug dependence: The property of body to react adversely with some symptoms when the concerned drug is withdrawn.
b. Why the reported case is more among adolescents?
Incidence among adolescents is more due to curiosity, experimentation, peer pressure etc.
c. What intervention could be planned for the adolescents so as to prevent them falling into the trap?
Awareness campaign at school level (assembly/plays/poster competition, peer talks, awareness in society (TV, media, nukkad natika etc.) Counseling.
d. How could this problem affect the individual, family and the society?
Affect at the level of self: Health issues (physical/psychological/social).
Affect at the level of family: Fights, stealing, crime.
Affect at the level of society: Crime rate, isolation etc.
OR
Ecological Indicators: The presence of dragonflies can reveal changes in the water ecosystems more quickly than studying other animals or plants. In fact, from the nymph to the adult stage, the dragonfly has a significant, positive ecological impact. Dragonfly eggs are laid and hatched in or near water, so
their lives impact both water and land ecosystems. Once hatched, dragonfly nymphs can breathe underwater which enables them to eat mosquito larvae, other aquatic insects and worms, and even small aquatic vertebrates like tadpoles and small fish and in the air. Adult dragonflies capture and eat adult
mosquitoes. Besides that the pesticide industry is booming with a wide variety of products available in the market to kill mosquito.
a. What is the basic concept of the above topic?
Bio-control
b. Mention two diseases that are less likely to occur in the areas where the above mentioned insect is prevalent.
Mosquito related diseases: Malaria, Yellow fever etc.
c. How the drop in the water table is going to affect the dragon fly?
Drop in water table will lead to reduced green cover, change in the flora and therefore fauna. This may reduce the available food items thereby reducing the population of dragon fly.
d. In a particular residential society with lot of green area, the pesticides were sprayed to kill the mosquitoes. The population of dragon fly also dropped drastically. What could be the reason for this observation?
Pesticides might have killed the mosquitoes, since it is the food of dragon fly, so population of predator gets reduced.
e. Dragon fly is a predator. Does it act as top carnivore? Give justification.
Dragon fly of course is a predator but not the top carnivore. There are many birds that depend on it. So it forms a part of the food chain.