BIOLOGY TIMES — January 2018

(ff) #1

  1. (d)

  2. (d) Stomatal opening is under the control of
    turgor pressure of the guard cells. Turgor pressure
    is controlled by the movement of minerals and
    sugar molecules in the guard cells.

  3. (c)

  4. (b) Kurasawa was investigating the mechanism
    by which the fungal pathogen Gibberela fujikorai
    led the foolish seedling disease in rice plants
    infected with this pathogen.

  5. (c) Cycas show symbiotic association of nitrogen
    fixing cyanobacteria in coralloid roots.

  6. (d)

  7. (c) Haemophilia is more commonly seen in
    human females as this disease is caused because
    of X-linked recessive mutation.

  8. (d)



  • A biennial is a plant that grows for two years
    before setting its seed and then dying. In the first
    year the plant grows a healthy root system, leaves
    and a short stem before becoming dormant over
    the winter months.

  • In the second year the plant grows quickly before
    flowering, setting seed and then dying.

  • Some of the more common bienniels are
    Foxgloves, Evening Primroses etc.

  • A perennial is a plant that lives for more than two
    years. The plant dies back each winter; however
    the root system survives the winter months so
    that the plant can regrow the following year.
    Some more common plants in this group are
    Lupins etc.



  1. (c) Prophase I of meiosis. This is the complex and
    longest phase. It is divided into five substages.

  2. (d)
    37. (c) Gel electrophoresis is a technique generally
    used in laboratories to separate charged molecules
    such as DNA, RNA, and proteins according to
    their size.
    38. (c) Vector is a DNA molecule used as a vehicle to
    artificially carry foreign genetic material into
    another cell where it can be replicated or
    expressed. Plasmid have that property and hence
    it’s a vector.
    39. (c) Stomata is an opening present in epidermal
    region of leaf used for gas exchange.
    40. (a) Methane is a major component of gobar gas.
    41. (a) Plants capable of C 4 photosynthesis carry on a
    more efficient form of photosynthesis. For C 4 type
    plants, 1) the light saturation point is higher and
    2) the light compensation point is lower than for
    C 3 plants.
    42. (c) Deserts have very hot days and very cold
    nights. Due to the bare plant cover, the soil of
    desert is much more exposed to these fluctuations
    as compared to that of other areas. During day
    time the soil becomes hot and in night it frequently
    becomes cool.
    43. (c) Human insulin consists of two short
    polypeptides chains linked together by disulphide
    bridges.
    44. (d) Water channel consists of eight different types
    of aquaporins.
    45. (c) In Mirabilis jalapa, hybrid between red and
    white flowered plants produces pink flowers in
    the F1 generation which is a fusion of red and
    white condition. This result shows that both red
    and white flowered condition is not dominant.
    Therefore, it is due to incomplete dominance.

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