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Exam 28: Protists

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Question 31

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A P. bursaria cell that has lost its zoochlorellae is said to be aposymbiotic. It might be able to replenish its contingent of zoochlorellae by ingesting them without subsequently digesting them. Which of the following situations would be most favourable to the reestablishment of resident zoochlorellae, assuming compatible Chlorella are present in P. bursaria's habitat?

A) abundant light, no bacterial prey
B) abundant light, abundant bacterial prey
C) no light, no bacterial prey
D) no light, abundant bacterial prey

E) A) and D)
F) A) and C)

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Question 32

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Which of the following statements about dinoflagellates is true?

A) They possess two flagella.
B) All known varieties are autotrophic.
C) Their walls are usually composed of silica plates.
D) Many types lack mitochondria.
E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.

F) A) and B)
G) A) and C)

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Question 33

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The following questions refer to the description below. Malaria is a global health problem in over 100 countries, killing about one million people every year. The protist, Plasmodium, that causes malaria lives in 2 hosts, mosquitoes and humans. Malaria is transmitted to humans by the Anopholes mosquito. -The use of DDT greatly decreased numbers of Anopholes mosquitoes in the 1960s, and drugs killed the Plasmodium. Now doctors tend to prescribe a combination of drugs against malaria. Why don't doctors prescribe a vaccine to combat malaria?

Use the following information to answer the questions below. Giardia lamblia is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the 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. Infection usually occurs by drinking untreated water that contains cysts. -Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate form of a ________, an organelle that is itself a degenerate form of a(n) ________.

Use the following information to answer the questions below. Giardia lamblia is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the 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. Infection usually occurs by drinking untreated water that contains cysts. -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

The motility that permits P. bursaria to move toward a light source is provided by

Why do photosynthetic protists play a critical role in aquatic ecosystems?

Including the membrane of the surrounding vesicle, how many phospholipid?(NOT lipopolysaccharide) bilayers should be found around each cyanelle, and which one of these bilayers should have photosystems embedded in it?

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 accurately describes the behaviour of Paramecium species that lack zoochlorellae in an aquarium with light coming from one side only?

Use the following information to answer the questions below. Giardia lamblia is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the 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. Infection usually occurs by drinking untreated water that contains cysts. -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 best evidence for not classifying the slime moulds as fungi comes from slime moulds'

The genome of modern chloroplasts is roughly 50% the size of the genome of the cyanobacterium from which it is thought to have been derived. In comparison, the genome of? P. chromatophora's cyanelle is only slightly reduced relative to the size of the genome of the cyanobacterium from which it is thought to have been derived. What is a valid conclusion that can be drawn from this comparison?

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of the white blood cells of animals (monocytes) . If one were to erect a taxon that included all organisms that have cells with pseudopods, what would be true of such a taxon?

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 pairs of protists and their characteristics is mismatched?

A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

The following questions refer to the description below. You and a friend were walking through a pet store looking at the different aquaria with fish. Most of the aquaria had fish that were healthy and colourful, but two tanks with many fish in them had fish with "fin and tail rot" caused by a pathogenic bacteria. You and your friend read that bacteria are found in most environments and that healthy fish are quite resistant to bacterial infections. -Test tube 2 contains

Use the following information to answer the questions 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. -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 relabelling P. chromatophora as a mixotroph?

If we were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then we would

Use the following information to answer the questions below. Giardia lamblia is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the 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. Infection usually occurs by drinking untreated water that contains cysts. -The primary treatment for giardiasis (infection with Giardia) , as well as for trichomoniasis (infection with Trichomonas vaginalis) and for 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 the parasites' flagella, as the drug's name might imply? 1. It would also harm the flagellated lining of the human intestine. 2. Entamoeba possesses pseudopods, not flagella, yet it is killed by Flagyl. 3. Prokaryotic flagella and eukaryotic flagella are radically different from each other and unlikely to be harmed by the same chemical. 4. Not all anaerobic gut bacteria possess flagella, yet it kills these bacteria.