Question

Reproduction in Paramecium is controlled by
A) Flagella
B) Micronucleus
C) Macronucleus
D) Cell Wall

Answer 1

Hint:Paramecium is a unicellular, microscopic, free-living organism. It is the best known single-celled organism in existence. Paramecium reproduces asexually, by binary fission.

Complete answer:
Paramecium is an example of ciliated and unicellular protozoa and is characterised by the presence of thousands of cilia all over its body.

Let us analyze each option to find out the correct answer.
>Option A: Flagella is a hairlike structure. It acts primarily as an organelle of locomotion in the cells of many living organisms. It is usually found in bacteria, archaea, and eukaryotes, though they are most commonly found in bacteria. They are typically used to propel a cell through the liquid. Therefore, this is an incorrect option.
>Option B: Paramecium has two types of nucleus- micronucleus and macronucleus. The micronucleus takes part in sexual reproduction. Organisms of the opposite sex meet and join each other at an oral groove. Micronucleus then divides meiotically and produces four haploid nuclei. Three nuclei disintegrate and the remaining one divides mitotically and the nucleus swaps into both of the cells. Then two haploid nuclei fuse in each cell and form a new diploid micronucleus. Hence, the micronucleus controls reproduction in Paramecium. Therefore, this is the correct option.
>Option C: Paramecium has two types of nucleus- micronucleus and macronucleus. Macronucleus performs common cellular functions. The micronucleus is a storage site for the germline genetic material of the organism. It gives rise to the macronucleus and is responsible for the genetic reorganization that occurs during conjugation (cross-fertilization). Therefore, this is an incorrect option.
>Option D: Cell wall is the outermost layer of the cell and is only found in plant cells. It is the outermost layer of the plant cell. It is made up of different types of polysaccharides depending on the cell type. It also helps in regulating the entry of particles from outside the cell to inside. Therefore, this is an incorrect option.

Thus, the correct option is (B) Micronucleus.

Note:Paramecium can reproduce both sexually and asexually.
(i) Sexual method of reproduction: It reproduces by conjugation, autogamy and rarely cytogamy.
(ii) Asexual method of reproduction: It reproducs by binary fission.