The Cysts of Giardia are Most Analogous to The

Question

The cysts of Giardia are most analogous to the
A) mitochondria of ancestral diplomonads.
B) nuclei of archaeans.
C) endospores of bacteria.
D) capsids of viruses.

Accepted Answer

Endospores are dormant, tough, and resistant structures formed by bacteria in response to unfavorable environmental conditions, such as extreme heat or lack of nutrients. Similarly, the cysts of Giardia are durable, dormant, monovalent structures formed by this protozoan parasite in response to harsh conditions, such as dehydration or digestive enzymes, that can survive for weeks or months outside a host. Therefore, the cysts of Giardia are most similar to endospores of bacteria. The mitochondria (A) are organelles found in eukaryotic cells and unlikely the best analogy. The nuclei (B) are membrane-bound compartments that store and protect genetic information in eukaryotic cells and are not comparable to cysts. The capsids (D) are the protein coverings of viruses that enclose genetic material and are not the best analogy for Giardia cysts.