Question

Binary fission in some organisms occurs in definite orientation in relation to the cell structures. One such organisms is:
A. Leishmania
B. Plasmodium
C. Amoeba
D. Bacteria

Answer 1

Binary fission is defined as the process in which an organism duplicates its genetic material and divides into two organisms so they possess one copy of DNA each. It is a kind of asexual reproduction.

Complete answer:
Binary fission is termed as a type of asexual reproduction. A unicellular organism for example bacteria and protozoa simply splits into two equal halves during cell division. In amoeba, splitting and division of the two cells during division can occur in any place in any plane.

Now let us find solution from given options:
Leishmania: Leishmania possess a whip-like structure (flagellum) at one end of the cell and binary fission occurs in a definite orientation in comparison to this structure.
Plasmodium: Plasmodium, the most perfect malarial parasite divides into many daughter cells simultaneously by multiple fissions.
Amoeba: Irregular fission can take place in any plane like amoeba. The parent lost its identity and gave rise to a new individual.
Bacteria: Longitudinal fission takes place along the longitudinal axis. e.g. some bacteria. Binary fission when occurs in bacteria the cell divides in two halves.

Hence, the correct answer is option (A)

Note: This kind of sexual reproduction and cell division is also used by some organelles like mitochondria. Leishmania is responsible for the development of a disease called Kala-azar. Kala-azar also known as Leishmaniasis. In this disease, parasites go into internal organs such as the liver, spleen and bone marrow. Symptoms of this disease include fever, weight loss, fatigue and anaemia.