Science (English Medium)
Academic Year: 2019-2020
Date & Time: 14th March 2020, 10:30 am
Duration: 3h
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General Instructions:
Read the following instructions very carefully and strictly follow them:
- Question paper comprises five sections: A, B, C, D and E.
- There are 27 questions in the question paper. All questions are compulsory.
- Section A question number 1 to 5 are multiple choice questions carrying 1 mark each.
- Section B question number 6 to 12 are short answer questions type-I, carrying 2 marks each.
- Section C contains number 13 to 21 are short answer questions type-II carrying 3 marks each.
- Section D contains number 22 to 24 are short answer questions type-III, carrying 3 marks each.
- Section E question number 25 to 27 are long answer questions, carrying 5 marks each.
- Answer should be brief and to the point also the above word limit be adhered to as far as possible.
- There is no overall choice in the question paper. However, an internal choice has been provided in two questions of 1 mark, one question of 2 marks, two questions of 3 marks and three questions of 5 marks questions. Only one of the choices in such questions have to be attempted.
- The diagram drawn should be neat proportionate and properly labelled, wherever necessary.
- In addition to this, separate instructions are given in each section and question, wherever necessary.
Louis Pasteur demonstrated that ______.
early life came from outer space
non-living chemicals produced living molecules
life comes from pre-existing life
life originated spontaneously
Chapter:
Mating of a superior male of a breed of a cattle to a superior female of another breed is called ______.
in breeding
out crossing
out breeding
cross breeding
Chapter:
Large-holes in ‘Swiss-Cheese’ are due to ______.
Propionibacterium sharmanii
Saccharomyces cerevisae
Penicillium chrysogenum
Acetobacter aceti
Chapter:
Increased concentration of DDT in fish-eating birds is due to ______.
eutrophication
bio-magnification
cultural eutrophication
accelerated eutrophication
Chapter:
The species-area relationship is represented on a log scale as ______.
inverted
rectangular hyperbola
hyperbola
linear
Chapter: [13] Biodiversity and Its Conservation
Which one of the following part of the plant when put into the soil is likely to produce new offspring?
Part of an internode
A stem cutting with a node
Part of a primary root
A flower
Chapter:
In a bacterium when RNA-polymerase binds to the promoter on a transcription unit during transcription, it ______.
terminates the process
helps remove introns
initiates the process
inactivates the exons
Chapter:
Name one air-borne and a waterborne disease in humans. List one specific symptom of each one of them.
Chapter:
Name the two techniques employed to meet the increasing demand of fish in the world.
Chapter:
Describe the contributions of Alexander Flenting, Ernest Chain and Howard Florey in the field of microbiology.
Chapter:
All cloning vectors do have a ‘selectable marker’. Describe its role in recombinant DNA-technology.
Chapter:
Mention how have plants developed mechanical and chemical defence against herbivores to protect themselves with the help of one example of each.
Chapter:
Both Thalassemia and colour blindness categorised as Mendelian disorders. Justify.
Chapter:
Suggest two advantages to a farmer for using apomictic seeds of hybrid varieties.
Chapter: [8] Strategies for Enhancement in Food Production
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Write the palindromic nucleotide sequence EcoRI recognises.
Chapter:
Draw the vector DNA and a foreign DNA showing the sites where EcoRI has acted to form the sticky ends.
Chapter:
Name the enzyme that helps in forming recombinant DNA.
Chapter:
Differentiate between “Pioneer-species”; “Climax-community” and “Seres”.
Chapter:
Explain any three ways other than zoological parks, botanical gardens and wildlife safaries, by which threatened species of plants and animals are being conserved ‘ex situ’.
Chapter:
Explain ‘Integrated organic’ farming as successfully practiced by Ramesh C. Dagar, a farmer in Sonepat (Haryana).
Chapter:
Explain the mode of action of Cu++ releasing IUDs as a good contraceptive. How is hormone releasing IUD different from it?
Chapter:
Why is ‘Saheli’ a preferred contraceptive by women (any two reasons)?
Chapter:
State any two ways the discovery of SNPs can be of importance to humans.
Chapter:
- Rearrange the following in the correct order of their appearance on Earth between two million years and 40,000 years back.
Neanderthals, Australopithecus, Homo erectus and Homo habilis. - Which one of the above
- had the largest brain size
- ate fruits
Chapter:
Explain Mendel’s “Law of segragation” in a typical monohybrid cross with the help of a suitable example.
Chapter:
Explain why bee-hives are setup on the farms for some of our crop-species. Name any two such crop species.
Chapter:
List any three important steps to be kept in mind for successful bee keeping.
Chapter:
Explain three different modes of pollination that can occur in a chasmogamous flower.
Chapter:
Explain the formation of placenta after the implantation in a human female.
Chapter: [2] Human Reproduction
“The population of a metro city experiences fluctuations in its population density over a period of time.”
- When does the population in a metro city tend to increase?
- When does the population in metro city tend to decline?
- If ‘N’ is the population density at the time ‘t’, write the population density at the time ‘t + 1’.
Chapter:
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Study the diagram showing the entry of HIV into the human body and the processes that are followed:
- Name the human cell ‘A’ HIV enters into.
- Mention the genetic material ‘B’ HIV releases into the cell.
- Identify enzyme ‘C’.
Chapter:
Following a road accident four injured persons were brought to a nearby clinic. The doctor immediately injected them with tetanus antitoxin.
- What is tetanus antitoxin?
- Why were the injured immediately injected with this antitoxin?
- Name the kind of immunity this injection provided.
Chapter:
Name the insect that attacks cotton crops and causes lot of damage to the crop. How has Bt cotton plants overcome this problem and saved the crop? Explain.
Chapter:
Explain the different steps carried out in Polymerase Chain Reaction, and the specific roles of the enzymes used.
Chapter:
Mention the application of PCR in the field of biotechnology.
Chapter:
Mention the application of PCR in the field of diagnostics.
Chapter:
Describe the process of double fertilisation in angiosperms.
Chapter:
Trace the development of polyploidal cell that is formed after double fertilisation in a non-albuminous seed and albuminous seed.
Chapter:
List any two reasons other than physical and congenital disorders for causing infertility in couples.
Chapter:
Explain how IVF as a technique helped childless couples in having children.
Chapter:
Why did T.H. Morgon select Drosophila melanogaster for his experiments?
Chapter:
How did T.H. Morgan disprove Mendelian dihybrid F2 phenotypic ratio of 9 : 3 : 3 : 1? Explain giving reasons.
Chapter:
List any four major goals of Human Genome project.
Chapter:
Write any four ways the knowledge from HGP is of significance for humans.
Chapter:
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