Question

While observing the permanent slide of Amoeba, Ramesh saw an oval shaped nucleus. This nucleus indicates ________.
a. Binary fission
b. Budding
c. Multiple division
d. None of the above

Answer 1

Hint: Amoeba is a single-celled organism that reproduces asexually by mitotic division. It divides into two equal-sized daughter cells after mitotic division.

Complete answer:
Amoeba is a single-celled organism that does not have a definite shape and moves with the help of pseudopodia (false feet). Its mode of nutrition is heterotrophic, that is, it cannot prepare its food. If a permanent slide of amoeba is observed under a microscope, an oval-shaped nucleus would be visible to us. This indicates that amoeba undergoes asexual reproduction through binary fission.

The asexual reproduction starts as amoeba undergoes mitosis. Due to mitosis, the genetic material (nucleus) present inside the amoeba gets replicated. Once the genetic material is replicated, the single-celled amoeba divides into two daughter cells. This indicates that the daughter cells are identical to each other and the parent cell.

The division of the nucleus in amoeba occurs through the process of karyokinesis. Once the karyokinesis is over, cytokinesis occurs. Due to cytokinesis, the cytoplasm of amoeba splits into two leading to the formation of two identical daughter cells. It occurs immediately after mitosis.

Additional Information:
Amoeba was first discovered by August Johann Rosel Von Rosenhof. Amoeba moves and feeds with the help of pseudopodia. They feed on bacteria, dead organic matter, etc. and ingest their food with the help of phagocytosis (it is a process in which a cell engulfs a particle using its plasma membrane).

Apart from that certain amoeba cause diseases like amoebiasis which is caused by Entamoeba histolytica and spread through contaminated food and water. It also includes other diseases like encephalitis, granulomatous amoebic meningoencephalitis, etc. Certain amoeba-like Naegleria fowleri which is also known as a brain-eating amoeba is fatal to humans and leads to instant death.

Note: All single-celled organisms reproduce asexually by undergoing mitotic or amitotic division and the offspring produced due to it are identical to each other and the parent. Asexual reproduction is the primary form of reproduction in single-celled organisms. In multicellular organisms, the sexual mode of reproduction is the common form.