Biology Today - February 2018

without involvement of fertilisation and meiosis.

15. Biogeography is the study of patterns of geographical
    distribution of plants and animals across earth and the
    changes in those distributions over time. Darwin’s finches of
    Galapagos islands illustrate adaptive radiation. They differ
    in size and shape of beak as they have adapted themselves
    according to the availability of food in that island.


16. Multiple Ovulation Embryo Transfer Technology (MOET) is
    a revolutionary technique for herd improvement. In this
    technique, a cow is administered with hormones of FSH like
    activity, to induce follicular maturation and super ovulation,
    LH, instead of one egg, which they usually give per cycle,
    they produce 6-8 eggs. The cow is either mated with the
    best bull or artificially inseminated. The embryos at 8-32
    cell stages are then recovered and transferred to surrogate
    mothers. The genetic mother is again available for another
    super ovulation.
    OR
    Assisted reproductive technologies (ART) include a number
    of special techniques which assist infertile couples to have
    children. Some important techniques of ART are (i) Test
    tube baby (IVF, ICSI) (ii) Artificial insemination technique
    (AIT) and (iii) Gamete intra Fallopian transfer (GIFT). In test
    tube baby technique, the fusion of ovum and sperm is done
    outside the body of woman and induced to form zygote in
    the laboratory. The zygote is then allowed to develop early
    embryo which is then implanted in uterus. So, this method is
    referred to as LQYLWUR fertilisation (IVF).


17. Baculoviruses infect the larval stages of many harmful
    insects such as ants, wasps and beetles. These viruses are
    excellent candidates for species–specific, narrow spectrum
    insecticidal applications. They have been shown to have no
    negative impacts on plants, mammals, birds, fish or even
    on non-target insects. This is very desirable when beneficial
    insects are been conserved to aid in overall integrated pest
    management (IPM) programme.


18. Innate immunity is present at the time of birth. It consists of
    different types of barriers :
    (i) Physical barriers : Skin on our body prevents entry
    of microorganisms. Mucus coating of the epithelium


19. (a) Association of sucker fish and shark is an example of
    commensalism where one individual is benefitted while the
    other remains unaffected. Sucker fish attaches itself to the
    under surface of shark by its holdfast and gets free ride,
    wide dispersal, protection and food.

(b) Mycorrhizae, association between fungi and the roots of
higher plants is an example of mutualism. It is a type of
interaction where both partners are benefitted with none of
the two capable of living separately.

11. The intimate connection between developing fetus and
    uterine wall of mother to exchange the materials is called
    placenta. The chorionic villi and uterine tissue become
    interdigitated with each other and jointly form the placenta.
    Placenta acts as an endocrine gland as it secretes a number of
    hormones such as estrogen, progesterone, human chorionic
    gonadotropin, human chorionic somatomammotropin,
    chorionic thyrotropin, chorionic corticotropin and relaxin.


12. Diagrammatic representation of process of transcription in
    bacteria is :
    3 c

Sigma factor

Promoter

RNA

RNA

Initiation

Elongation

Termination

DNA helix

Terminator

RNA

polymerase

Rho factor

RNA polymerase

V

V

U

5 c

3 c

5 c

5 c

5 c

5 c

5 c

3 c

3 c

3 c

3 c

13. Two chromosomal disorders in humans are : Down's syndrome
    and Klinefelter's syndrome. Down's syndrome is an autosomal
    aneuploidy that occurs due to trisomy of 21st chromosome.
    The affected person has rounded face, protruding
    tongue, folded eyelids, flat hands, stubby fingers, broad
    palm with palmer crease, short and broad neck, low IQ.
    Klinefelter's syndrome (XXY) is caused by presence of
    extra X-chromosome due to union of nondisjunct XX egg
    and a normal Y sperm or normal X egg and abnormal XY
    sperm LH, it is trisomy of sex(X) chromosome. These are
    genetically sterile male individuals with underdeveloped
    testes, gynaecomastia, etc.


14. Development of fruits without fertilisation is called
    parthenocarpyLH, the phenomenon of development of ovary
    into fruit without the act of fertilisation. The parthenocarpic
    fruits are seedless, HJ., banana, guava, apple, pineapple,
    etc. Parthenocarpy can be induced artificially by :
    (i) Spraying auxins and gibberellins (ii) Low temperature
    In agamospermy, embryo and seeds are produced asexually

MPP-10 CLASS XI ANSWER KEY

1. (a) 2. (d) 3. (b) 4. (c) 5. (d)


2. (c) 7. (a) 8. (b) 9. (d) 10. (d)


3. (c) 12. (c) 13. (a) 14. (d) 15. (a)


4. (c) 17. (c) 18. (b) 19. (c) 20. (c)


5. (b) 22. (b) 23. (a) 24. (c) 25. (d)


6. (b) 27. (b) 28. (b) 29. (b) 30. (c)


7. (b) 32. (b) 33. (b) 34. (a) 35. (c)


8. (c) 37. (c) 38. (d) 39. (b) 40. (c)