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 How are the members of the genus glomus useful to organic farmers?
Ans. a) Absorb Phosphorus from soil
b) Protect from root borne pathogen
Q.2. Mention the four steps involved in the isolation of DNA from a bacterial cell for biotechnology experiments.
Ans. i) Bacterial cell treated with lysozyme.
ii) RNA is removed by RNases and proteins are removed by proteases
iii) Purified by addition of chilled Ethanol
iv) Removed by spooling
OR
Mention the two objectives of setting up the organization GEAC by the Indian Govt
Ans. Objective of GEAC:
a) Ethical standards to evaluate the morality of human activities.
b) To have regulations, as genetic modifications of organisms have unpredictable results.
Q.3. List the four causes (Evil Quartets) responsible for loss of biodiversity.
Ans. i) Fragmentation and Habitat Loss.
ii) Over exploitation of species by man
iii) Invasion of alien species.
iv) Co-extinction.
Q.4. Name two viral diseases that are transmitted by mosquito vectors? Name the causal organism of typhoid.
Ans. a) Dengue and Chicken guinea.
b) Salmonella typhium.
OR
a) Write the causative organism of a amoebiasis.
Ans. Entamoeba histolytica
b) Mention any three characteristics symptoms of the disease.
Ans. Constipation, Abdominal cramps and pain, stool with excess mucus and blood clots.
Q.5. a) Mention the cause of ADA deficiency and its effect on the human body
Ans. caused due to deletion of gene coding for the enzyme Adenosine deaminase.
b) What can be a possible permanent cause?
Ans. Genetically engineered lymphocytes have fix life span; patient require periodic infusion.
Gene isolated from bone marrow cells producing functional ADA is introduced in embryonic stage.
Q.6. Define Gause competitive release? Give an example where an animal-plant interaction involves coevolution.
Ans. It states that two closely related species competing for the same resources.
cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually. Eg- plant pollen and wasp interaction
SECTION B
Q.7. a) What is insertional inactivation?
Ans. When an alien DNA or rDNA is ligated within the coding sequence of an enzyme, the enzyme become inactivated, this phenomenon is called as insertional inactivation.
b) State the roles o: (1) Ori and (2) Ropgene in E. Coli Cloning Vector pBR3222
Ans. (1) Ori (origin of Replication) is a sequence of DNA where replication starts
(2) Ropgene- codes for the proteins involved in replication of the plasmid.
Q.8. Differentiate between a Normal cell and Cancerous cell?
Ans.
Q. 9. Explain life cycle of Malarial parasite. Name its infective stage also?
Ans. Life cycle of malarial parasite:
Mosquito bite release sporozoite — > Asexual Division in Liver — > Asexual Multiplication in RBC — >RBC Ruptive release Hemozoin Gametes are produced — > Fertilization in — > Mosquitoes’ intestine — > Zooid is stored in salivary glands.
Infective stage of plasmodium is sporozoite
OR
a) Define Allergy.
Ans. The exaggerated response of the Immune system to certain antigens present in the environment is called allergy
b) Name the cells and the chemical responsible for causing allergic reaction in our body.
Ans. Most of the cells release chemicals like histamine and serotonin.
c) Mention any four symptoms of allergy.
Ans. Symptoms
i) sneezing,
ii)watery eyes and
iii)Running nose
Q.10 What is RNAi? Mention the role of Agrobacterium in the production of Nematode- resistant tobacco plant?
Ans. RNAi refers to the silencing of the specific mRNA by complementary double- standard RNA that binds to and prevent the translation of RNA.
Ti plasmid of agrobacterium is used as a vector to introduce the nematode-specific genes into host pant in such a way that it produces both sense and anti-sense RNA in the host.
Q.11 Give three reasons that account for greater biological diversity in the tropics than in the temperate regions.
Ans. i) speciation is a function of time, temperate regions were subjected to frequent glaciations in the past, while tropics remained undisturbed.
ii) Tropical environment are less seasonal and more constant, more predictable.
iii) More solar radiations in the tropics contributes to more productivity.
Q.12 Write the function of (i) statin (ii) Cyclosporine-A
Also write the source from where they are obtained.
Ans. i) statin — obtained from manescuspurpureus —- used as blood cholesterol lowering agent
ii) cyclosporine A : Trichoderma polysporum used as immuno suppressive agents.
SECTION C
Q.13 Observe the outline/structure of a drug given below and answer the following questions:
a) Name of the group of drugs, it represents and write the scientific name of its source plant.
Ans. It is a cannabinoid — cannabis sativa — source plant.
b) Write the four forms in which these are consumed.
Ans. Hashish, Ganja, Marijuana, Charas
c) Mention the methods in which they are taken.
Ans. Taken by inhalation and oral ingestion
d) Name of the organ system of the body, which it’s affected.
Ans. cardio-vascular system is affected
OR
a) Name the type of growth above ‘a’ and mention when this type of growth curve occurs in the nature.
Ans. Exponential growth curve and when resources are unlimited.
b) Why is the growth curve ‘b’ said to be logistic?
Ans. When resources are limited, predation pressure.
c) Differentiate between the two growth curves ‘a’ and ‘b’.
Ans. k represents carrying capacity
carrying capacity refers to the maximum number of individuals that a given environment can support, beyond which further growth is not possible.