Chapter 21, Problem 17STP

Summary Introduction

To write:

The reproduction in paramecia and amoebas.

Introduction:

Protists are eukaryotic organisms that are not animals, plants or fungi. Although they have a cellular structure similar to other eukaryotes, their reproductive methods shoe remarkable differences. Some reproduce asexually by mitosis while some exchange genetic material during meiosis. They are classified by their method of obtaining nutrition as animal-like protists, plantlike protists and fungus-like protists.

Explanation of Solution

A paramecium is a unicellular protozoan. It is completely covered by cilia which hare used for movement. Amoebas are enclosed in an outer cell membrane and inner thickened cytoplasm with a nucleus, food vacuole and sometimes, contractile vacuole. The mode of reproduction of paramecia and amoebas are discussed below.

Paramecia	Amoebas
1. They reproduce asexually by binary fission where the macronucleus elongates and splits. Genetic information is exchanged by conjugation. During conjugation, two paramecium combine to form a cytoplasmic bridge where their diploid micronuclei undergo meiosis.	1. They have a nucleus and membrane bound organelles.

Conclusion

The Prokaryotic cells do not have a nucleus or membrane bound organelles while eukaryotic cells have a nucleus and membrane bound organelles.