Download high order thinking skills (hots ).

HIGH ORDER THINKING SKILLS (HOTS ).
UNIT –I
1. Both tapeworm and earthworm are hermaphrodites .How do they differ from each other with
reference to fertilisation ?
= Tapeworm-external fertilisation.
Earthworm- Internal fertilisation.
2. Explain why meiosis and gametogenesis are always interlinked .
= Gametes are haploid ,resultant of meiosis in sexually reproducing organisms.
3. Explain giving two reasons why pollengrains can be best preserverd as fossils.
= Presence of sporopollenin ( one of the biologically most resistant chemical substance )
4. What would be the genetic make up of apomictic embryos ? Can they be called clones.
= Products of mitosis , hence getically and morphologically identical.
5. Meiotic division during oogenesis is different from that in spermatogenesis . Explain how and why ?
=
Oogenesis
Spermatogenesis
1. Primary oocyte under goes meiosis-I to
1. Primary spermatocyte under goes first
form a larger secondary oocyte and a
meiotic division to form two equal size
smaller first polar body.
cells,the secondary spermatocytes.
2. The secondary oocyte undergoes meiosis2. The secondary spermatocyte undergoes
ii to form a larger cell, the Ootid and a
meiotic-ii to form two cells of equalsizes
smaller cell called second polar body.
called spermatids.
3. Only one of the cells produced is
3. All four are functional.
functional.
6. Amniocentesis which is used for sex determination is baned in our country. Is is correct or not ? Justify
your statement.
=Amniocentesis is useful for knowing the sex of the child and alsofor genetic disorders of the
foetus.The peolple are misusing the technology for female foeticides.Thats why the government is
banned forusing of amniocentesis for identifying sex.
7. ART is providing various methods for infertile couples looking for parenthood. Is it adoptablet to all
people or not ? Supprot your answer ? If not what is the alternative ?
= Implementation of ART requires high precision handling by specialised proffessionals and expenssive
instrumentation. These facilities are available only in few centres. It is affordable to only limited number
of people. So ART is not adoptable to all.
Alternate is to adopt orphaned ,destitute child by the couples which is legally acceptable.
UNIT -II
GENETICS AND EVOLUTION.
8. Aa Bb was crossed with aabbb. What would be the phenotypic ratio of the progeny ? Mention the term
to denote this kind of cross.
= Phenotypic Ratio = 1:1:1:1
Test cross.
9. In a dihybrid test cross the parental recombination frequency was found to be 70 % and 30 %
respectively. Is it following the law of independent Assortment or not ? Justify.
= Hint. Test cross recombinants and parental frequency would be 50:50. If recombination frequency is
less than 50 means the genes are linked. Hence not following Law of indipendent assortment.
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10. Thalsssemia alpha is different from thalassemia beta. Justify.
11.
12.
13.
14.
15.
16.
Thalassemia alpha
Thalassemia beta
1. It is under the control of two genes HbA1
1. It is controlledby a single gene HbB on
and HbA2 on chromosome 16.
chromosome 11.
2. The synthesis of alpha chain is impaired.
2. The synthesis of beta chain is impaired.
In normal Mendelian monohybrid cross two forms of the traits will be exhibited. But in Antirrhinum
after the monohybrid cross the colour of the flowers are seen as red,pink and white. Is it possible or
not ? Support your statement.
= Incomplete dominance.
A normal visioned woman ,whose father is colour blind , marries a normal vision man. What would be
the probability of her sons and daughters to be colour blind. Explain with the help of a pedigree chart.
= Hint . Pedigree chart.
Colourblindness gene is located on the X-chromosome-X-linked inheritance.
Why do RNA viruses undergo mutation and evolution faster than most of the other viruses ?
= Additional –OH group is a reactive group. Presence of U in place of T. Also RNA is single styranded and
less stable.
Why is it that transcription and translation can be coupled in prakaryotic cells but not in eukaryotic
cells?
= In prokaryotes there are opnly exons but in eukaryotes both exons and introns are present.
Which of the two – the coding strand or the template strand of DNA ,will the transcribed RNA resemble
more ? Why ? How will they yet differ from each other ?
=The RNA will resemble the coding strand more.
Because RNA is complementary to template strand and template strand is complementary to the coding
strand. Hence coding strand and RNA are similar except Deoxyribose sugar and Thymine ( difference of
RNA and DNA).
Are the thorns of Bougainvillea and tendrils of Cucurbita homologous or analogous ? What type of
evolution has brought such a similarity in them ?
= Bothe are modified axillary buds .Hence homologous. Divergent evolution.
UNIT –III
BIOLOGY IN HUMAN WELFARE.
17. How do neutrophills act as a cellular barrier to pathogens in human?
= Phagocytosis of pathogen.
18. If a patient is advised antiretroviral therapy, which infection is he suffering from ? Name the causative
organism.
= AIDS
Pathogen – HIV
19. All normal cells have inherant characteristic of becoming cancerous. Explain.
= All Normal cells contain protooncogenes ,which can be changed into cancer genes through mutation.
20. Describe the technology that has successfully increased the herd size of cattle in a short time to meet
the increasing demands of growing human population.
=MOET.
21. Microbes can be used to decrease the use of chemical fertilisers and pesticides . Explain how this can be
acomplished.
=Biofertilisers and biopesticides.
22. Do you think microbes can also be used as source of energy ? If yes ,how ?
= Methagens in biogas production. In ruminants digestion of cellulose.
23. Which metabolic pathway is responsible for puffed up appearance of the Idli ?
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= Fermentation.
UNIT-IV
BIOTECHNOLOGY.
24. Restriction enzymes should not have more than one cloning site in a vector . Comment.
= Generation of several segments will complecate gene clonning.
25. While carrying out a PCR ,denaturation step was missed . What will be its effect on the process ?
=Two bstrands of DNA will not be separated and primer will not be able to anneal to the template.
26. A scientist found a rare plant species without seeds and flowers and want to increase their number
and which are diseasr free. Suggest the method that can be adopted by the scientist.
= Through meristem culture.
27. Why do prokaryotes ( bacteria ) have restriction enzymes but not eukaryotes ?
=Prokaryotes have restriction enzymes to restrict the growth of bacteriophage.
28. Hpw is the gene z ( for beta galactosidase ) used as a marker ?
= Insertional inactivation.
29. How is Bt cotton made to attain resistance against bollworms ?
= cry gene in Bacillus thurigiensis is isolated and introduced in cotton plant. The product of cry gene is
resistant to bollworm.
30. ICAR was planning to release GM crop ( Bt –brinjal ) to farmers. But the farners protested against the
Bt-brinjal. Is their protest justifiable of not ? Support your answer.
=Scientifically protest is not correct. Explain based on the Bt-cotton.
UNIT –V
ECOLOGY.
31. Which of the two stenothermals or eurythermals ,shows wide range of distribution on earth and why ?
=Eurythermals can tolerate and survive in wide range of temperatures.
32. How are the mountain dwellers adapted to live in oxygen deficient condition ?
=Physiological adaptation-RBC count will be more.
33. ‘ All successions proceed to a similar climax community the Mesic ‘. Explain.
= Primary,secondary, hydrarch,xerarch –all successions leads to same final climax stage – the forest.
34. Explain with the help of two examples how the pyramid of numbers and the pyramid of biomass can be
inverted ?
= Pyramid of Number in a tree ecosystem ( Parasites ) and pyramid of biomass in an aquatic
ecosystem.
35. Why is it said that ecosystems with diversity can withstand environmental changes better than others ?
= Advantages of biodiversity. No biodiversity the entire living organisms may be removed either due to
disease or predation, climatic changes ,etc.
36. =Rreligious beliefs and traditions are helping in the preservation of plants and animals. Do you agree
with this statement or not ? Justify.
= Worshiping of plants and animals in different religions, medicinal plants , ornamental plants Sacret
grooves,lakes ,rivers ,etc.
37. Why does biomagnifications occur with certain substances ? Name two such substances.
= Because some chemical substances are persistent and non-biodegradable and gets accumulated in
the body tissues.
DDT, Mercury.
Boimagnification occurs through the food chain.
38. ‘ Urbanisation and industrialization pose a threat to the coastal areas of earth due to rise of sea level’.
Explain with reasons.
= Due to global warming.
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