Question

1. Giardia intestinalis and Trichomonas vaginalis are both eukaryotic organisms that lack mitochondria.
How is each transmitted?
What does each cause?
How does each organism obtain energy without mitochondria?

2. Taxonomic classification of both protozoa and algae is a little tricky… Why are protozoa and algae not just grouped in with animals or plants?

3.Why is schizogony (multiple fission) of a protozoan advantageous to the protozoan but disadvantageous to the host?

Answer 1

1) Giardia intestinalis is transmitted through contaminated food or water. It causes diarrheal illness known as giardiasis.

Trichomonas vaginalis is transmitted by sexual contact. It causes infection in the vagin-a or urethra called trichomoniasis.

Both Giardia intestinalis and Trichomonas vaginalis lack mitochondria and therefore necessary enzymes and cytochromes to conduct oxidative phosphorylation. Since they have no mitochondria to complete aerobic respiration these organisms carry out anaerobic metabolism.  T. vaginalis uses a small amount of enzymes to provide energy via glycolysis and further conversion of pyruvate to hydrogen and acetate in an organelle called the hydrogenosome.

-----------------------------------------------------------------------------------------------------------------

2) Protozoa have an animal-like behavior whereas algae are have plant-like ; but both lacks characteristics to be classified as animals or plants.

Protozoa are single celled eukaryotic organisms that possess animal-like behaviors, such as motility and predation. They do not have a cell wall, as found in plants. Since they are single cellular, they are not classified as animals.

Algae possess chloroplast organs and produce energy to power the cell through photosynthesis and the Calvin cycle. However, they lack many other structures of true plants like roots, stems, or leaves.