Download Chapter 15 Answers to Even Numbered Study Questions

PRINCIPLES OF MODERN MICROBIOLOGY
Mark Wheelis
ANSWERS TO STUDYQUESTIONS
Chapter 15
Eucaryotic Microbes
2. Some protistan lineages, most notably many of the algal groups, contain macroscopic
representatives; however, most of these lack extensive tissue and organ differentiation. The true
macroscopic lineages, the plants and animals, are each recent derivatives of a protistan lineage: the
plants from the green algae (which we did not discuss here), and the animals from the
choanoflagellate lineage. Nearly all the protistan lineages are of much greater antiquity than the
plants and animals, and are only very distantly related to them.
4. Human pathogens are found in the diplomanads, parabasalids, kinetoplastids, amoebas and
amoebaflagellates, and apicomplexans. Dinoflagellates can also cause disease by producing a toxin,
but they themselves are not pathogens. (Note: a several other groups contain human pathogens;
only those that are mentioned in this chapter are included here.)
6. The ciliate micronucleus contains a diploid set of chromosomes, and its replication is responsible
for transmission of genetic information from one generation to the next. It is also involved in sexual
reproduction when that occurs.
The macronucleus is formed by division of the micronucleus, followed by repeated rounds of
replication without mitosis, forming a polyploid nucleus. It is the site of most transcription.
8. In both the stamenopiles and alveolates there are shared ultrastructural characteristics that suggest
that lineages that otherwise differ greatly are in fact related. In the stamenopiles, it is the possession
of distinctive flagella, decorated by fine hairs. In the case of the alveolates it is possession of
alveoli--a system of vesicles that lies beneath the cell membrane, sometimes containing pellicular
plates, sometimes not.