Exam 25: The Origin and Diversification of Eukaryotes

You are given five test tubes, each containing an unknown protist, and your task is to read the following description and match these five protists to the correct test tube. In test tube 1, you observe an organism feeding. Your sketch of the organism looks very similar to Figure 25.1. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 2 and 3. Chemical analysis of test tube 3 indicates the presence of substantial amounts of silica. Chemical analysis of test tube 2 indicates the presence of a chemical that is toxic to fish and humans. Microscopic analysis of organisms in test tubes 2, 4, and 5 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 4 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 5 reveals the presence of one large nucleus and several small nuclei in each organism. Figure 25.1 The next few questions refer to the following description and Figure 25.1. -Test tube 2 contains

The evolution of multicellularity in animals has primarily occurred by the

Judging from Table 25.1 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?

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

If true, which of the following would be most important in determining whether P. chromatophora's cyanelle is still an endosymbiont, or is an organelle, as the term cyanelle implies?

The closest living relative of P. chromatophora is the heterotroph P. ovalis. What type of evidence permits biologists to make this claim about relatedness?

The next few questions refer to the following description. 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. -Which term best describes the symbiotic relationship of well-fed P. bursaria to their zoochlorellae?

Which of the following represents the true significance of the finding that the cyanelles of P. chromatophora stem from a different type of cyanobacterium than gave rise to chloroplasts?

The next few questions refer to the following description. 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. -Which term most accurately describes the nutritional mode of healthy P. bursaria?

Which of the following statements about dinoflagellates is true?

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 5) Entamoeba

Based on the phylogenetic tree in the figure given below, which of the following statements is correct?

The closest living relative of P. chromatophora is the heterotroph P. ovalis. P. ovalis uses threadlike pseudopods to capture its prey, which it digests internally. Which of the following, if observed, would be the best reason for relabeling P. chromatophora as a mixotroph?

The next few questions refer to the following description. 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

The chloroplasts of all of the following are thought to be derived from ancestral red algae, except those of

During passage through the large intestine, a trophozoite will often secrete a case around itself, forming a cyst. Cysts contain four haploid nuclei. When cysts "hatch" within a new host, two trophozoites are released. Thus, which of the following must happen within the cyst, prior to hatching? 1. meiosis 2) nuclear division 3) S phase 4) binary fission

Unlike most excavates, Giardia trophozoites have no oral groove and are unable to form food vacuoles. Thus, we should expect its nutrition (mostly glucose) to come from

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

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of which group(s)?

The cysts of Giardia are most analogous to the