Question

Reproduction in Paramecium is controlled by
A) Macronucleus
B) Micronucleus
C) Both A and B
D) None of the above

Answer 1

Paramecium is an unicellular organism which has a body shape similar to that of a sole of a shoe. It is an eukaryotic species and belongs to the genus protozoa.

Complete answer:
Reproduction is the process by which new organisms are produced. There are two types of reproduction,

1. Asexual mode of reproduction
   2)Sexual mode of reproduction

OptionA: Paramecium features two different kinds of nuclei called the micronucleus and the macronucleus. The macronucleus performs certain cellular functions. Therefore, this is the incorrect option.
Option B: The micronucleus is majorly inclined towards the reproduction process. The organism of the opposite sex meets each other and join at the oral groove. It is then the micronucleus divides meiotically to result in the production of four haploid nuclei three of which disintegrate with time and the fourth one undergoes mitotic division while the nucleus swaps in between both the cells. Thereafter, the two haploid nuclei undergo fusion to form a new diploid micronucleus. Therefore, this is the correct option.
Option C: As only micronucleus is responsible for reproduction, therefore this is the incorrect option. Macronucleus is involved in cellular functions.
Option D: Micronucleus has a role in reproduction, therefore, this is the incorrect option.
Thus, the correct option is (B) Micronucleus.
Note: In papramecium both sexual and asexual mode of reproduction is seen.
Asexual reproduction: -It occurs via binary fission and only under unfavourable conditions
Sexual reproduction:-It occurs via conjugation and when conditions are favourable It can also occur via autogamy and autogamy (self-fertilization)