Question

Which of the following is not a character of Protista?
A. Protists are eukaryotic
B. Some protists have cell walls
C. Their mode of nutrition is both autotrophic and heterotrophic
D. They have a nucleoid

Answer 1

Hint: The kingdom Protista consists of a large number of eukaryotic organisms. These are organisms that have a true nucleus that encloses the genetic material. They are not fungus, plants, or animals. They reproduce either by sexual reproduction or asexual reproduction. They have plasmalemma surrounded by cellulose walls. The nucleoid is the space in the prokaryote where its genetic material is present.

Complete answer: Protists are simple eukaryotic organisms having a true nucleus inside the cell. The term eukaryotic means true fully developed nucleus. The nucleus is the circular membrane-bound organelle found in the cytoplasm of cells usually in the center. It consists of the genetic material of the cell.
-This genetic material controls and mediates cell functioning. Some cells that are prokaryotes do not have a defined specialized organelle that encloses their genetic material. The prokaryotes have free-floating genetic material present in the cytoplasm of cells. The area where the genetic material is present in the prokaryotes is called the nucleoid. The protists lack nucleoid.
-The protist cell consists of various organelles that are enclosed by a plasma membrane or plasmalemma. This plasmalemma is sometimes covered by an external cell wall called pellicle, cuticle, or cellulose cell wall.
-They are both autotrophic and heterotrophic. This means that protists can make their food on their own by the process of photosynthesis due to the presence of some pigments. Some protists are dependent on other cells for their food and thus are called heterotrophic. So, from the above discussion, we can conclude that protists do not have a nucleoid. Rather, the nucleoid is a characteristic feature of prokaryotes.
Therefore, the right answer is option D.

Note: Some of the protists are parasitic in nature. They cause significant diseases in animals and plants. As the protists share their metabolic pathways with animal and plant eukaryotic cells, their elimination is difficult. A drug that acts on protists will eventually be harmful to the infected host cells.