Plasmodium falciparum is a protozoan parasite known to cause malaria, an illness characterized by fever, chills, and flu-like symptoms. Which of the following is the most likely reason why P. falciparum would be classified as a eukaryotic organism?

Question

Plasmodium falciparum is a protozoan parasite known to cause malaria, an illness characterized by fever, chills, and flu-like symptoms.  Which of the following is the most likely reason why P. falciparum would be classified as a eukaryotic organism?

Quizplus · Accepted Answer

11ecba2d_1011_a844_a3bf_1feef69d7ffa_MD0008_00 Eukaryotic cells have distinct characteristics that distinguish them from prokaryotic cells. For example, membrane-bound organelles are unique to eukaryotic cells and allow for the compartmentalization of specific cellular processes (eg, transcription in the nucleus, aerobic respiration in the mitochondria). In addition, eukaryotic cells have a unique mechanism for processing messenger RNA (mRNA). Eukaryotic mRNA is initially transcribed as pre-mRNA, containing both introns (noncoding sequences) and exons (coding sequences). Following transcription, the spliceosome (an RNA and protein complex) removes introns from the pre-mRNA molecule to form mature mRNA in a process known as RNA splicing. This mature mRNA is transported out of the nucleus and into the cytoplasm, where it is translated into protein. Protozoa (eg, P. falciparum) are single-celled eukaryotic organisms, and therefore possess all of the unique characteristics of eukaryotic cells, including a mechanism for splicing introns from mRNA in the nucleus. (Choice A) Both eukaryotic and prokaryotic cells are able to reproduce sexually. Sexual reproduction in eukaryotic cells occurs via fusion of gametes (products of meiosis), and prokaryotic cells reproduce sexually through conjugation. Therefore, sexual reproduction would not be a defining characteristic that could be used to classify P. falciparum as a eukaryotic organism. (Choice C) The cell wall is a rigid polysaccharide layer surrounding the cell membrane that provides protection and structural support in certain cell types. Most prokaryotic cells have cell walls, but only some eukaryotic cells (ie, plants, fungi) have them. Because a cell wall can be found in both prokaryotes and eukaryotes, it would not be a distinguishing characteristic for classifying P. falciparum as eukaryotic. In addition, protozoa lack cell walls. (Choice D) Because eukaryotic and prokaryotic cells are surrounded by a cell membrane, this cannot be used to classify P. falciparum as eukaryotic. Educational objective: Eukaryotic and prokaryotic cells are similar in that both have mechanisms of sexual reproduction and are enclosed by a plasma membrane. In addition, all prokaryotes and some eukaryotes have cell walls. However, eukaryotic cells are unique in that they have membrane-bound organelles as well as a mechanism for intron splicing by the spliceosome.

Plasmodium Falciparum Is a Protozoan Parasite Known to Cause Malaria