Chapter 28 - Protists Flashcards
All protists are:
A) unicellular. B) eukaryotic. C) symbionts. D) monophyletic. E) mixotrophic.
B) eukaryotic.
Biologists have long been aware that the defunct kingdom Protista is polyphyletic. Which of these statements is most consistent with this conclusion?:
A) Many species within this kingdom were once classified as monerans.
B) Animals, plants, and fungi arose from different protist ancestors.
C) The eukaryotic condition has evolved more than once among the protists.
D) Chloroplasts among various protists are similar to those found in prokaryotes.
E) Some protists, all animals, and all fungi share a protist common ancestor, but these protists, animals, and fungi are currently assigned to three different kingdoms.
C) The eukaryotic condition has evolved more than once among the protists.
According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?
A) from infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy-transfer reactions
B) from engulfed, originally free-living proteobacteria
C) by secondary endosymbiosis
D) from the nuclear envelope folding outward and forming mitochondrial membranes
E) when a protoeukaryote engaged in a symbiotic relationship with a protocell
B) from engulfed, originally free-living proteobacteria
Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?
A) conjugation B) horizontal gene transfer C) binary fission D) phagocytosis E) meiosis
B) horizontal gene transfer
An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?
A) It relies on photosystems that float freely in its cytosol.
B) It must have gained extra mitochondria when it lost its plastids.
C) It engulfs organic material by phagocytosis or by absorption.
D) It has an endospore.
E) It is protected by a case made of silica.
C) It engulfs organic material by phagocytosis or by absorption.
Which of the following was derived from an ancestral cyanobacterium?
A) chloroplast B) mitochondrion C) hydrogenosome D) mitosome E) Two of the responses above are correct.
A) chloroplast
Which of the following pairs of protists and their characteristics is mismatched?
A) apicomplexans–internal parasites B) golden algae–planktonic producers C) euglenozoans–unicellular flagellates D) ciliates–red tide organisms E) entamoebas–ingestive heterotrophs
D) ciliates–red tide organisms
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.
A) They possess two flagella.
You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm, each featuring the 9 + 2 filament pattern. It has well-developed organelles and three nuclei, one large and two small. This organism is most likely to be a member of which group?
A) foraminiferans B) radiolarians C) ciliates D) kinetoplastids E) slime molds
C) ciliates
Which of the following is characteristic of ciliates?
A) They use pseudopods as locomotory structures or as feeding structures.
B) They are relatively specialized cells.
C) They can exchange genetic material with other ciliates by the process of mitosis.
D) Most live as solitary autotrophs in fresh water.
E) They are often multinucleate.
E) They are often multinucleate.
Which process results in genetic recombination, but is separate from the process by which the population size of Paramecium increases?
A) budding B) meiotic division C) mitotic division D) conjugation E) binary fission
D) conjugation
Why is the filamentous morphology of the water molds considered a case of convergent evolution?
A) Water molds evolved from filamentous fungi.
B) Body shape reflects ancestor-descendant relationships among organisms.
C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer.
D) Filamentous body shape is evolutionarily ancestral for all eukaryotes.
E) Both the first and second responses above are correct.
C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer.
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
A) increase the dosage of the least-expensive antimalarial drug administered to humans.
B) increase the dosage of the most common pesticide used to kill Anopheles mosquitoes.
C) introduce a predator of the malarial parasite into infected humans.
D) use a “cocktail” of at least three different pesticides against Anopheles mosquitoes.
E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.
E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.
Diatoms are mostly asexual members of the phytoplankton. Diatoms lack any organelles that might have the 9 + 2 pattern. 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?
A) How does carbon dioxide get into these protists with their glasslike valves?
B) How do diatoms get transported from one location on the water’s surface layers to another location on the surface?
C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters?
D) How do diatoms with their glasslike valves avoid being shattered by the action of waves?
E) How do diatom sperm cells locate diatom egg cells?
C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters?
Which of the following is a characteristic of the water molds (oomycetes)?
A) the presence of filamentous feeding structures
B) zoospores that are spread by breezes
C) the same nutritional mode as possessed by cyanobacteria
D) a morphological similarity to fungi that is the result of common ancestry
E) a feeding Plasmodium
A) the presence of filamentous feeding structures
