MCQ-7

31.In which of the following dinoflagellates bioluminescence was reported for the first time?

a)  Noctiluca

b)  Ceratium

c)  Alexandrium

d)  Pyrocystis

32. Food particles in Ameoba are less active in

       a)  Circumfluence

       b)  Circumvallation

       c)  Invagination

       d)  Import

33. Wriggling type of locomotion is seen in

      a)  Paramecium

      b)  Zooflagellates

      c)  Globigerina

      d)  Sporozoans

34. A horticulturist used a certain bacteria X to cure off the bitterness of leaves of tea and tobocco.Name the bacteria X.

      a)  Pseudomonas fluorescence

      b)  Bacillus megatherium

      c)  Clostridium butylicum

      d)  Acetobacter aceti

35) select the correct statement regarding asexual reproduction in fungi

      a)  Cilia help the Zoospores to swim in aquatic habitat for proper dispersal.

      b)  Oidia are individual cells that multiply by budding.

      c)  Conidia are motile exogenous spores

      d)  Basideospores are meiospores which are formed endogenously

EXPLANATION:

31. Answer: (a)

·       Noctiluca, genus of marine dinoflagellate in the family Noctilucaceae.

·       one of the most commonly occurring bioluminescent organisms in coastal regions of the world.

·       The scintillating effect of Noctiluca’s bioluminescence, which is most conspicuous at night during a bloom (population increase), was historically a mysterious phenomenon, frequently contributing to what was called “burning of the sea” or “sea sparkle” by sailors and coastal inhabitants

·       hazardous to fish and certain other marine species.

·       Noctiluca, which is a large (about 1–2 mm [0.04–0.08 inch] in diameter), spherical, gelatinous single-celled organism

·       The cell contains a centrally located nucleus.

·       Noctiluca reproduce through binary fission (separation of the cell into two bodies) or multiple fission (separation of the cell into more than two bodies).

32. Answer: (a)

Amoeba ingests food in four ways:

·       Import- This method involves the taking in of food on contact. The food passively sinks into the body by rupturing plasmalemma and ectoplasm at the point of contact. The ruptured site soon heals up.

·       Invagination - The food is adhered by the toxic and sticky secretion of ectoplasm. The food organism is sucked in upon contact with the ectoplasm, by the formation of the ectoplasmic tube which later becomes a food vacuole.

·       Circumfluence - Amoeba extends its pseudopodia around the motionless organism like bacteria on contact and envelops it completely with cytoplasm. The enclosing of the captured organism results in the formation of food vacuole.

·       Circumvallation - Amoeba engulfs an active prey like a flagellate or ciliate.It sends out pseudopodia around the prey, forming a cup-like structure called food-cup. The opening of the food-cup constricts leaving a pore which soon closes.

33) Answer: (d)

Wriggling locomotion:

It is slow worm-like movement which is performed with the help of a wave of contraction and expansion in the body, e.g., sporozoans, no flagellates, euglenoids.

34) Answer: (b)

Curing of tea leaves is accomplished by bacteria. Leaves of tea and tobacco are cured off their bitterness with the help of certain bacteria, e.g.,Bacillus megatherium.beans of coffee and cocoa are similarly cured. 

35)

The zoospores are special kind of motile and flagellated spores produced inside the zoosporangia. They are generally naked (without cell wall). The flagella helps to swim in aquatic habitats for proper dispersal. 

Conidia  are asexual spores that are formed at the end or the side of the conidiophore, They are non-motile and must be dispersed via the wind or other external transport. Conidia are the fungus's primary method of reproduction.

A basidium is a club shaped microscopic sporangium or spore producing structure which produce basidiospores . They are the sexual spores produced exogenously in a fruiting body called basidiocarp.