Use the following choices to answer questions 8–10:
a. Apicomplexa
b. ciliates
c. dinoflagellates
d. Microsporidia


These are obligate intracellular parasites that lack mitochondria.

Verified step by step guidance

1. Identify the key characteristics of each group listed in the choices.
2. Recall that obligate intracellular parasites are organisms that can only reproduce inside the cells of a host.
3. Consider the absence of mitochondria as a distinguishing feature.
4. Review the characteristics of Microsporidia, which are known to be obligate intracellular parasites and lack mitochondria.
5. Conclude that the group described in the problem is Microsporidia.

Key Concepts

Obligate Intracellular Parasites

Obligate intracellular parasites are organisms that can only reproduce and survive within the cells of a host. They rely on the host's cellular machinery for their metabolic processes and replication, making them dependent on the host for their life cycle. This characteristic is crucial for understanding their biology and the challenges they pose in terms of treatment and control.

Lack of Mitochondria

The absence of mitochondria in certain parasites indicates a significant adaptation to their intracellular lifestyle. Mitochondria are typically responsible for energy production through aerobic respiration, so these organisms have evolved alternative metabolic pathways to generate energy. This adaptation can affect their susceptibility to drugs and their ecological interactions.

Microsporidia

Microsporidia are a group of obligate intracellular parasites known for their unique life cycle and lack of mitochondria. They are primarily known to infect animals, including humans, and can cause opportunistic infections, especially in immunocompromised individuals. Understanding Microsporidia is essential for recognizing their impact on health and the challenges they present in clinical settings.