Exam 25: The Origin and Diversification of Eukaryotes

Please use the following information to answer the question(s) below. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people. It can infect people when they drink water contaminated with feces containing Giardia cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. -Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate form of ________, an organelle that is itself a degenerate form of ________.

The last common ancestor of fungi and animals was most likely a

Why is the filamentous morphology of the slime molds considered a case of convergent evolution with fungi?

Which of the following statements concerning protists is true?

Please use the following information to answer the question(s) below. Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people. It can infect people when they drink water contaminated with feces containing Giardia cysts. Upon ingestion, each cyst releases two motile cells, called trophozoites. These attach to the small intestine's lining via a ventral adhesive disk. The trophozoites anaerobically metabolize glucose from the host's intestinal contents to produce ATP. Reproduction is completely asexual, occurring by longitudinal binary fission of trophozoites, with each daughter cell receiving two haploid nuclei (n = 5). A trophozoite will often encyst as it passes into the large intestine by secreting around itself a case that is resistant to cold, heat, and dehydration. -The primary treatment for giardiasis (infection with Giardia), trichomoniasis (infection with Trichomonas vaginalis), and amoebic dysentery (infection with Entamoeba histolytica) is a drug marketed as Flagyl (generic name is metronidazole). The drug also kills anaerobic gut bacteria. Consequently, which of these are cues that Flagyl's mode of action has nothing to do with attacking or disabling flagella, as the drug's name might imply? 1) Flagyl would also harm the flagellated lining of the human intestine. 2) Entamoeba possesses pseudopods, not flagella, yet it is killed by Flagyl. 3) Not all anaerobic gut bacteria possess flagella, yet flagyl kills these bacteria.

Some scientists who study organismal classification believe that green algae should be in an expanded "plant" kingdom called Viridiplantae. If land plants are excluded from this kingdom, then what will be true of it?

Please use the following information to answer the question(s) below. Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. -The diatoms' porous shells are hard but often break and result in sharp edges. Crop farmers incorporate DE into their soil to help kill insect pests. When insects encounter DE, sharp shell edges cut through their exoskeletons and then softer, broken down DE absorbs insect body fluids, thereby causing the insects to die due to dehydration. Why might farmers who raise large livestock also use DE in the animals' feed?

Please use the following information to answer the question(s) below. Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. -The motility that permits P. bursaria to move toward a light source is provided by

Which two genera have members that can evade the human immune system by frequently changing their surface proteins? 1) Plasmodium 2) Trichomonas 3) Paramecium 4) Trypanosoma

Rhizarians that feed using threadlike pseudopodia include which of the following group(s)? I. forams II. red algae III. cercozoans IV. green algae

Please use the following information to answer the question(s) below. Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "cyanelles." The cyanelles are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants. -What must occur for asexual reproduction to be successful in P. chromatophora? 1) mitosis 2) S phase 3) meiosis 4) equal distribution of cyanelles during cytokinesis

The oldest fossil eukaryote that can be resolved taxonomically is of

According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?

Please use the following information to answer the question(s) below. You are given four test tubes, each containing an unknown protist. Your task is to read the following description and match these four protists to the correct test tube. When red and blue light are shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals thousands of cilia on the surface of the organism. -Test tube 2 contains

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

The evolution of complex multicellularity in eukaryotes

Which of the following is (are) mutualistic partnerships between a protist and a host organism? I. cellulose-digesting gut protists-wood-eating termites II. dinoflagellates-reef-building coral animals III. Trichomonas-humans IV. algae-certain foraminiferans

Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as Dictyostelium?

Please use the following information to answer the question(s) below. Diatoms are encased in cases (valves) made of translucent hydrated silica whose thickness can vary. The material used to store excess calories can also vary. At certain times, diatoms store excess calories in the form of the liquid polysaccharide laminarin and at other times as oil. The table shows data concerning the density (specific gravity) of various components of diatoms and of their environment. -Judging from the table and given that water's density and, consequently, its buoyancy decrease at warmer temperatures, in which environment should diatoms (and other suspended particles) sink most slowly?

Diatoms are mostly asexual members of the phytoplankton. They obtain their nutrition from functional chloroplasts, and each diatom is encased within two porous, glasslike valves. Which question would be most important for one interested in the day-to-day survival of individual diatoms?