Biology 2014 JAMB Past Questions - Question 41: When the adults have reached a certain degree of weakness, the process of binary fission is replaced by conjugation in

Correct Answer

A

Explanation

Binary fussion is a form of asexual reproduction in which the organism divides into two starting from the nucleus (mega and micronuclei) and later the cytoplasm. after repeated binary fission, Paramecium becomes weak and looks for a healthier paramecium. These two paramecia pair up : fuse at their oral groove Meganuclei disappear whiie micronuclei divides. Thereexchange of a portion of the micro nucleus One portion of the nucleusmoves through the fused oral grove into the opposite partner. After theexchange, they separate. The two portions micronucleus fuse and each paramecium continues with process of binary fission. Conjugation is a type of sexual reproduction in which the gametes are alike. Spirogyra Paramecium and Rhizopus carryout this f o r m of sexual reproduction Exampie, two spirogyra filaments lie side by side. Protrusion occurs: between opposite cells these protrusions grow and touch walls dissolve and a conjugation tube is formed. The cell content (protoplasm)of opposite : rounds up to become gametes. One of the gametes moves across the conjugation tube into the c and fuses with the opposite gamete to form a zygote. This act of sexual reproduction, gamete that moves is labelled male While the stationary game the female. Thereafter spirogyra filament separates the zygote develops into zygote: which germinates to form spirogyra filament. Plasmodium is a malaria parasite transmitted into human r through the bite of an infected female anopheles mosquito Euglena and Amoeba are living protozoans found in star water. They reduce asexually by binary fussion.