Download DELHI PUBLIC SCHOOL, DHALIGAON SPECIAL ASSIGNMENT

DELHI PUBLIC SCHOOL, DHALIGAON
SPECIAL ASSIGNMENT – 2015-16
CLASS – XII
Human Reproduction
1. Name the cells that nourish the germ cells in the testis.
2. How oogenesis is different from spermatogenesis with respect to initiation of the process?
3. What is the function of acrosome in human?
4. Name the embryonic stage that gets implanted in the uterine wall of human female.
5. What are the layers of the uterine wall? Write its function.
6. Explain the hormonal regulation of spermat genesis and oogenesis.
7. Explain the fate of trophoblast cell and inner cell mass of blastula.
8. What is corpus luteum? Write its function.
9. Explain the process of spermatogenesis with suitable diagram.
10. Explain the hormonal regulation in different phases of oogenesis.
11. Explain the process through which the fertilized ovum gets implanted in the uterus after fertilization.
12. Name the source of gonadotropins in human females. Explain the changes brought about in the ovary by these
hormones during menstrual cycle.
13. Describe in sequence the formation of an ovum from an oogonium in a human female.
14. Explain the role of accessory glands in human male reproductive system.
15. What is placenta? How it forms? Write its function.
Reproductive Health
1. Name two STDs transmitted through contaminated blood.
2. Expand GIFT, ICSI, IUI, ZIFT
3. Give one reason for a statutory ban on amniocentesis.
4. Why CuT considered a good contraceptive to space children?
5. What is oral contraceptive? What are the possible side effects associated with OC?
6. Suggest and explain any three Assisted Reproductive Technologies to an infertile couple.
7. What is the significance of reproductive health in the society?
8. Mention the characteristics of an ideal contraceptive.
9. What are STDs? Name two STDs cause by bacteria, virus and fungi each.
10. What are IUDs? Why IUDs are very popular as contraceptive methods?
Human Health and Disease
1. State the function of mast cells in allergy response.
2. Why do pollen grains of some flowers trigger sneezing in some people?
3. A boy of 10 years had chicken pox. He is not expected to have the same disease for the rest of his life. Mention
how it is possible.
4. What role do macrophage play in providing immunity to humans?
5. How do neutrophils act as a cellular barrier to pathogens in humans?
6. How does a vaccine for a particular disease immunize the human body against that disease?
7. Name an opioid drug and its source plant. How does the drug affect the human body?
8. Write the scientific names, symptoms and organ affected by disease elephantiasis and tyohoid.
9. Differentiate between benign and malignant tumours.
10. How is an autoimmune disease caused? Give one example.
11. Describe the role of lymph nodes in providing immunity.
12. How do macreophages in the human body act as HIV factory?
13. A person is suffering from amoebiasis. Mention the pathogen that causes it and one organ of the body that gets
affected.
14. Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body?
15. List the harmful effects caused by alcohol.
Strategies for Enhancement in food production
1. Why are living plant cells said to be totipotent?
2. Why is south Indian sugarcane preferred by agriculturists?
3. Name the organism commercially used for the production of single cell protein.
4. How are biofortified maize and wheat considered nutritionally improved?
5. What is micropropagation? Why are the plants produced by micropropagation called somaclones?
6. Explain the advantages of animal inbreeding programme. Mention when inbreeding depression would occur.
7. Differentiate between inbreeding and out breeding in cttles.
8. Expand MOET. Explain the procedure of this technology in cattle improvement.
9. How can crop varities be made disease resistance to overcome food crisis in India? Explain. Name one disease
resistance variety of wheat resistance to leaf and stripe rust and Brassica resistance to white rust.
10. What is plant breeding? List the steps involve in plant breeding programme.
Organism and populations
1. Why are green plants not found beyond a certain depth in the ocean?
2. An exotic variety of prickly pear introduced into Australia turned out to be invasive. How was it brought under
control?
3. How do animals like fish and snails avoid summer related unfavourable conditions.
4. What is an interaction called, when an orchid grow on a mango plant?
5. Comment on the interaction between a clown fish living among the tentacles of a sea anemone.
6. Mention any two activities of animals which get cues from diurnal and seasonal variations in light intensity.
7. List any two physiological responses that help you to gradually get acclimatized to high altitudes, when you go
from the plain.
8. Why are small birds like humming birds not found in polar regions? Explain.
9. How does Monarch butterfly defend itself from predators? Explain.
10. How does the mediterian orchid, ophrys ensure its pollination by bees?
11. Mention the changes the koel must have undergone in order to achive brood parasitism, during the course of
evolution.
12. Write the equation for exponential and logistic growth curve with a suitable graph. Which growth curve is
considered as more realistic?
13. Differentiate between mutualism & competition, and Commensalism & Amensalism
14. List any four abiotic components that lead to variations in the physical and chemical conditions of different
habitats. Explain the impact of these components on the distribution of organisms in different habitats.
15. List the attribute that populations have but not individual.
Ecosystem
1. What is net primary productivity of an ecosystem ? How is it different from gross primary productivity?
2. Define standing crop and standing state of an ecosystem.
3. ‘A given species may occupy more than one trophic level in the same ecosystem at the same time’. Explain with
an example.
4. Global carbon is fixed in the ecosystem through photosynthesis. Explain any two ways by which carbon is
returned to the atmosphere.
5. State the difference between the first trophic levels of detritus food chain and grazing food chain.
6. What do you mean by the term Ecosystem? Name the components of an ecosystem.
7. Name the functional aspects of an ecosystem.
8. What do you understand by stratification in an ecosystem. Explain with an example.
9. What is meant by primary productivity? Differentiate between GPP and NPP. On what factors primary
productivity depends?
10. What does secondary productivity in an ecosystem indicate? List any two factors by which productivity is
limited in aquatic ecosystems.
11. What is decomposition? State the significance of decomposition in an ecosystem. Explain the steps involve in
the process of decomposition and the factors affecting decomposition.
12. Differentiate between food chain and food web.
13. What are the two types of food chains? Write three point of difference between them.
14. Write the characteristics of energy flow in a food chain.
15. Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels? Explain with an
example.
16. What does the pyramid in ecology represent? What are the limitations of ecological pyramids?
17. Explain the different types of pyramid and also show the inverted pyramid with an example.
18. What is ecological succession? Differentiate between Primary and secondary succession.
19. Explain Hydrarch and Xerarch succession with an example of each.
20. What is climax community? How is climax community established?
21. Carbon cycle in nature is a biogeochemical event. Explain.
22. Draw the pyramid of biomass in a sea and in a forest. Explain giving reasons why the two pyramids are different.
23. Explain how phosphorus get cycled through nature.
24. Differentiate between standing state and standing crop.
25. Write the important features of a sedimentary cycle in an ecosystem.
Biodiversity
1. Define the term biodiversity. Name the three important components of biodiversity.
2. Explain the three hypothesis for the greatest level of species richness in the tropics.
3. How the species diversity varies along the latitude?
4. Explain Alaxander Von Humboldt’s observation on species area relationship. Draw the graph and write the
equation.
5. What is the significance of the slope of regression in a species area relationship?
6. Explain with example the importance of species diversity to the ecosystem
OR
How is biodiversity important for ecosystem function?
7. Why certain regions have been declared as biodiversity ‘hot spots’ by environmentalist of the world? Name
any two hot spot regions in India.
8. What does the term genetic diversity refer to? What is the significance of large genetic diversity in a
population?
9. List the features that makes a stable biological community.
10. How is the sixth extinction presently in progress is different from the previous episodes?
11. What is IUCN red list? Give any two uses of this list.
12. Which region of the world is considered as the ‘Lungs of the planet’? Give two reasons for its degradation.
13. What are the various causes of biodiversity loss? Explain with example.
14. Explain the reason for conserving biodiversity.
15. What are the different approaches for conservation of biodiversity?
16. What is cryopreservation? Give its one use.
17. Differentiate between in situ and ex situ conservation.
18. What are sacred groves? What is their role in conservation?
19. Explain the historic conventions on biological diversity and the measures taken to conserve biodiversity.
20. How the loss of biodiversity will affect an ecosystem?
Environmental Issues
1.
2.
3.
4.
5.
Define the term Pollution?
What do you mean by air pollution? Write the causes and harmful effects of air pollution.
What are the different ways to control air pollution?
What are the strategies taken to control the air pollution in Delhi?
Why CNG is better fuel to overcome the problems of burning fossil fuel?
6. What are the harmful effects of noise pollution? What are the regulations made mandatory to protect our self
from noise pollution?
7. What is BOD? How the domestic waste and industrial efflurnts does affect the BOD in water bodies?
8. What is algal bloom? How is it harmful to aquatic life?
9. What is bio magnification? Explain with an example how bio magnification is related to food chain?
10. What is Eutrophication? Explain its consequences on the life of plants and animals living in such water. Why is
oxygen depletion in an eutrophicated water body faster at night than during day?
11. Explain the strategy followed by the people of town Arcata for Integrated waste water treatment.
12. What is ‘EcoSan’? How is it better than traditional toilets?
13. Mention how e-waste is produced and disposed off. Write the solution for its treatment.
14. What is ozone shield and why is it important? Write the causes and consequences of ozone layer depletion.
15. What is global warming? Write its causes and list four strategies for reducing global warming.
16. Explain two instances where degradation causes due to improper resource utilization and maintenance.
17. Write the causes and consequences of deforestation.
18. How local communities participate in conservation of forest?
19. Chloroflurocarbon are widely used as refrigerants. Then why is it suggested to reduce its emission as far as
possible? Explain.
20. Why organic farming is considered as ecofriendly? Explain.
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DELHI PUBLIC SCHOOL, DHALIGAON
Special Assignment – XII
1. Why does corpus luteum secrete large amount of progesterone during luteal/secretory phase of the menstrual
cycle?
2. Write the number of cells in the following stages, Zygote, Morula, Blastocyst, Blastomeres.
3. Mention the different steps in spermatogenesis and oogenesis.
4. Name two hormones that can be found only in the blood of a pregnant woman. Mention the source
organ/tissue that secretes each of them.
5. What name is given to the cells of inner cell mass, that have the potential to give rise to all tissues and organs in
a human being?
6. Classify the following contraceptive measures into different methods of birth control.
7. How can the pregnancy due to unprotected sex be prevented?
8. What do you mean by reproductive health? Mention the difference ways in which people are made aware of
the significance of reproductively healthy society?
9. A couple is eager to know the sex of their unborn child. What diagnostic technique will you suggest? What social
abuse is associated with the application of this technique?
10. What complication will occur if STD’s are not treated at the early stage?
11. A man with blood group O and his wife with blood group AB claim a child with blood group AB as their son. With
punnett square justify their statement?
12. State Mendel’s principle of independent assortment. Explain with suitable crosses how Mendel arrived at this
conclusion.
13. A homozygous tall pea plant with green seeds is crossed with a dwarf pea plant with yellow seeds: i) what
would be the phenotype and genotype of F1 ?
ii) Work out the
phenotypic ratio of F2 generation with the help of a punnett square.
14. Inheritance pattern of flower color in garden pea plant and snapdragon differs. Why is this difference observed?
Explain showing the crosses up to F2 generation.
15. Explain the pattern of inheritance of haemophilia in humans, Why is the possibility of a human female becoming
haemophilic extremely rare? Explain.
16. In one family each of the four children has a different blood group. Their mother is group A and the father is
group B. Explain this pattern of inheritance with the help of a cross along with the genotype.
17. Explain the sex determination mechanism in humans. How is it different in birds?
18. The human male never passes on the gene for red green colour blindness to his son. Explain.
19. Why do the sons of a haemophilic father never suffer from this trait?
20. Explain the genetic mechanism of Down’s syndrome, Turner’s syndrome and klinefelter’s syndrome.
21. Explain the role of 35S and 32P in the experiments conducted by Hershey and Chase.
22. A typical mammalian cell has 2.2 meters long DNA molecule where as the nucleus in which it is packed
measures about 10-6m. Explain how such a long DNA molecule is packed within a tiny nucleus in the cell.
23. Differentiate between
i) RNA
polymerase and DNA polymerase.
ii) Leading and
lagging strand
iii) Template and coding strand
24. What is splicing? Why is splicing necessary in eukaryotic genes?
25. How the codon AUG perform dual function?
26. How will you show that sickle cell anemia is caused due to frameshift mutation?
27. Three codons on mRNA are not recognized by tRNA. What are they< What is the general term used for them?
What is their significance in protein synthesis?
28. Why lac operon is called an inducible operon? Explain.
29. What is the significance of VNTR in DNA fingerprinting?
30. How did Griffith explain the principle of transformation? Explain the biochemical mechanism of Griffith
experiment.
31. Explain Operin-Haldane experiment on abiotic origin of life.
32. What is meant by homologous organ? Taking suitable example, explain how they support the theory of organic
evolution.
33. Why are the wings of butterfly and a bat said to be analogous? Name the type of evolution supported by it.
34. How do Darwin’s finches provide the biogeographical evidence in favour of evolution?
35. How does industrial melanism in Biston betularia illustrate the action of natural selection?
36. What is Hardy-Weinberg theory of genetic equilibrium? What are the factors affecting the genetic equilibrium?
37. Why small animals are rarely found in the Polar Regions? Explain.
38. How do organisms manage with stressful conditions existing in their habitat for short duration? Explain with the
help of one example each.
39. Show the graphical representation of population growth and explain which model is more realistic and why?
40. Name the interaction in each of the following:
i) Cuckoo lays her eggs in the crow’s nest
ii) Orchid grows on a mango tree
iii) Ticks live on the skin of dogs
iv) Sea anemone is often found on the shell of hermit crab
v) Cuscuta growing on a shoe flower plant
vi) Mycorrhzae living on the roots of higher plants
vii) Clown fish living among the tentacles of sea anemone
41. Why is predation required in a community of different organism?
42. Explain with an example the Guase’s competitive exclusion principle.
43. Enumerate the defense mechanisms evolved by prey species to lessen the impact of predation with an example
of each.
44. What is meant by ecological succession? Differentiate between pioneer community and climax community.
45. Due to uncontrolled excessive hunting, the population of tiger in a forest has become zero. Discuss the longterm effects of this situation on the population of deer in that forest.
46. The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil,
temperature etc. Discuss.
47. How is the presently occurring species extinction different from the earlier mass extinctions?
48. What is IUCN red list? Give any two use of this list.
49. Differentiate between in situ and ex situ approaches of conserving biodiversity.
50. Explain the hypothesis which explains the existence of greater biodiversity in tropical regions than in temperate
regions.
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