Chapter 28, Problem 28.1CR

Describe similarities and differences between protists and other eukaryotes.

Summary Introduction

To analyze: The similarities and differences between the protists and other eukaryotes.

Introduction: The “endosymbiont theory” predicts that the eukaryotic cells emerged from the engulfing of the early archaebacterial cells and the proteobacterial cells leads to the formation of the eukaryotic cells.

Explanation of Solution

The protists and eukaryotes have many similarities, and it is evident in their structural and functional classifications. It includes a wide variety of organisms present in nature like the diatoms, dinoflagellates, slime molds, golden and brown flagella, ciliates, radiolarians, chlorophytes, amoebas, and the fungi.

The similarities between the protists and other eukaryotes are as follows:

• The presence of organelles like the nucleus, Golgi apparatus, mitochondria, and the lysosomes is evident in the eukaryotic cells like the animal and the plant cells.
• The presence of chlorophyll is evident in the eukaryotic cells like the plant cells.
• The ability to phagocytose cells is called mixotrophy, which resembles the phagocytic activity of the macrophages present inside the human body.
• The sequencing analysis revealed that the mitochondrial genome of the eukaryotes like the plants and animals has emerged from the protists.
• The red, green, and brown algae were phagocytocized by the heterotrophic eukaryotic cells leading to the formation of the new species by the process of secondary endosymbiosis.

The differences between the protists and other eukaryotes are as follows:

Criteria	Protists	Other Eukaryotes
Number of cells	Single or multicellular	Multi-cellular
Metabolism	Some species of protists lack the electron transport system and cannot utilize oxygen for the functioning of the metabolism. They use the biochemical pathways for the synthesis of the metabolic food inside the cells.	Other eukaryotes have well developed electron transport system for metabolism.
Chloroplast	Chloroplast is present in some protists.	Chloroplast is only present in plants and not in other eukaryotes.
Reproduction	Syngamy and meiosis conjugation	Fertilization and meiosis