Exam 29: Protists

Consider the following data: (a)Most ancient eukaryotes are unicellular.(b)All eukaryotes alive today have a nucleus and cytoskeleton.(c)Most ancient eukaryotes lack a cell wall.Which of the following conclusions could reasonably follow the data presented?

Figure 29.2 -Refer to Figure 29.2 and consider the following data: Brown algae (protists)include unicellular and multicellular organisms.Red algae (protists)include unicellular and multicellular organisms.Amoebae (protists)include unicellular and multicellular organisms.Which of the following conclusions is consistent with the data presented?

A particular species of protist lacks the ability to engulf food and does not contain chloroplasts.However,gene sequencing data indicate that this species evolved from a lineage containing many species with the ability to engulf food.What does this information suggest about this species of protist?

In an area with a high abundance of algal blooms,the introduction of _____ might alleviate the severity of the blooms.

Which of the following protist lineages is appropriately paired with its supportive and/or protective structure?

One of the fish in your aquarium dies.Adding which protist to the water would allow you to avoid flushing the dead fish by speeding its decay?

Which of the following statements is consistent with the assertion that protists are paraphyletic?

The manufacture of which of the following products involves using materials that once belonged to a Phaetophyte?

Figure 29.5 -Which of the following might be a result of adding a secondary consumer (a species that feeds on primary consumers)to the aquatic ecosystem illustrated above?

Which of the following groups is matched with an incorrect anatomical feature?

Figure 29.3 Use the following information when answering the corresponding question(s). The mechanism of cell crawling in protist species is not well defined.The textbook states that pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in mammalian muscle contraction).However,prior to the study described below,no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists.Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist;but physiological studies had failed to show a functional link between actin,myosin,and cell crawling. In a study by N.Poulsen et al.(Diatom gliding is the result of an actin-myosin motility system,Cell Motility and the Cytoskeleton 44 (1999):23-22),researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin. -Refer to the study by Poulsen et al.and Figure 29.3.Cultures of a species of diatom were treated with BDM,a reversible inhibitor of myosin function.Which of the following predictions is consistent with the hypothesis that an actin-myosin interaction is necessary for motility?

Which of the following eukaryotic lineages contains species that all lack functioning mitochondria?

Figure 29.3 Use the following information when answering the corresponding question(s). The mechanism of cell crawling in protist species is not well defined.The textbook states that pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in mammalian muscle contraction).However,prior to the study described below,no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists.Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist;but physiological studies had failed to show a functional link between actin,myosin,and cell crawling. In a study by N.Poulsen et al.(Diatom gliding is the result of an actin-myosin motility system,Cell Motility and the Cytoskeleton 44 (1999):23-22),researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin. -Refer to the study by Poulsen et al.and Figure 29.3.The data graphed in Figure 29.3 could be an artifact if latrunculin A kills this species of diatoms (i.e. ,that may be why the cells are not moving).Which of the following would be the best evidence that latrunculin A is not killing the cells?

Figure 29.1 Use the following information to answer the corresponding question(s). Giardia intestinalis can cause disease in several different mammalian species,including humans.Giardia organisms (G.intestinalis)that infect humans are similar morphologically to those that infect other mammals;thus they have been considered a single species,though other species in the Giardia genus infect other organisms.However,G.intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999,a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species.The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G.intestinalis and a few other morphologically distinct species of Giardia.The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. -By examining the phylogenetic tree diagrammed in Figure 29.1,what conclusion can you draw about the species G.microti?

Which of the following characteristics is true of all protists?

A particular species of protist has obtained a chloroplast via secondary endosymbiosis.How can you tell?

What is necessary in order for symbiosis to occur?

According to the endosymbiotic theory,why was it adaptive for the larger (host)cell to keep the engulfed cell alive,rather than digesting it as food?

Which of the following statements best describes the term synapomorphy?

Figure 29.1 Use the following information to answer the corresponding question(s). Giardia intestinalis can cause disease in several different mammalian species,including humans.Giardia organisms (G.intestinalis)that infect humans are similar morphologically to those that infect other mammals;thus they have been considered a single species,though other species in the Giardia genus infect other organisms.However,G.intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999,a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species.The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G.intestinalis and a few other morphologically distinct species of Giardia.The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. -According to the phylogenetic tree in Figure 29.1,Giardia intestinalis constitutes a _____ group.