Title: Protists
Course: Question Banks

Q: Most protists are ________.
- enormous multinucleated organisms (Incorrect. There are large, multinucleated protists but not a majority of them.)
- multicellular (Incorrect. While there are some truly multicellular protists, there are not many.)
- microscopic unicellular organisms (Correct. The majority of protists are microscopic and single-celled.)
A: microscopic unicellular organisms

Q: Which is an example of a protist?
- a prokaryotic single-celled organism (Incorrect. Protists are not prokaryotes.)
- a prokaryotic multicellular organism (Incorrect. Protists are not prokaryotes.)
- a eukaryotic single-celled organism (Correct. Protists are the non-animal, non-plant, non-fungi members of the domain Eukarya.)
A: a eukaryotic single-celled organism

Q: Pellicles are ________.
- a protective covering on protists composed of silica (Incorrect. Pellicles are not made of silica.)
- a supportive shell composed of cellulose (Incorrect. Pellicles are not made of cellulose.)
- flexible, interlocking protein strips around protists (Correct. The pellicle is like a flexible coat of armor around protists.)
A: flexible, interlocking protein strips around protists

Q: The classic amoeba “oozing” movement is facilitated by ________.
- the concerted effort of cilia (Incorrect. Amoeba do not use cilia to move.)
- truncated flagella whipping together (Incorrect. Amoeba do not use truncated flagella to move.)
- pseudopodia extending from the cytoplasm (Correct. Some protists, generally called amoebas, move by extending bits of cytoplasm that adhere to a substrate and pull along the main body.)
A: pseudopodia extending from the cytoplasm

Q: The movement of ________ is facilitated by the concerted effort of cilia.
- amoeba (Incorrect. Amoeba do not move using cilia.)
- euglena (Incorrect. Euglena do not move by cilia.)
- paramecium (Correct. Paramecium use cilia to move.)
A: paramecium

Q: Movement toward a light source is known as ________.
- photoresponsiveness (Incorrect. This is not the correct term for movement toward light.)
- photoreception (Incorrect. This is not the correct term for movement toward light.)
- phototaxis (Correct. Taxis is movement in response to a stimulus; photo indicates that the stimulus is light.)
A: phototaxis

Q: Mixotrophs are notable for being able to ________.
- harvest sunlight to make their own food (Incorrect. Many organisms are able to perform photosynthesis—they harvest sunlight to make food.)
- act as heterotrophs (Incorrect. The world is full of heterotrophs. . . . Eat or be eaten!)
- switch between autotrophic and heterotrophic roles (Correct. Mixotrophs switch between making their own food using solar energy or consuming other organisms; it depends on the available resources in the environment.)
A: switch between autotrophic and heterotrophic roles

Q: ________ survive by absorbing nutrients from dead organisms or organic wastes.
- Amoebas (Incorrect. Amoebas are predators.)
- Mixotrophs (Incorrect. Mixotrophs switch between making their own food using solar energy or consuming other organisms; it depends on the available resources in the environment.)
- Saprobes (Correct. Saprobes function in environmental recycling by obtaining nutrients from dead organisms or waste.)
A: Saprobes

Q: Amoebas ingest food through ________.
- pinocytosis (Incorrect. Pinocytosis does not take in large particles such as food.)
- exocytosis (Incorrect. Exocytosis is the process of expelling materials from cells, not taking it in.)
- phagocytosis (Correct. Phagocytosis is the ingestion of food particles from the environment using a membrane sac.)
A: phagocytosis

Q: True slime molds reproduce by ________.
- longitudinal binary fission (Incorrect. Sometimes Paramecium exist this form of asexual reproduction.)
- sexual reproduction (Incorrect. Few protists undergo sexual reproduction.)
- multiple fission (Correct. True slime molds simultaneously divide into many daughter cells.)
A: multiple fission

Q: Sexual reproduction in protists often occurs when ________.
- other members of the same species are encountered (Incorrect. The presence or absence of another member of the same species does not trigger sexual reproduction.)
- a protist is parasitic (Incorrect. Sexual reproduction is not restricted to parasitic protists.)
- environmental stress occurs (Correct. Sexual reproduction is often associated with environmental stressors such as low nutrients as it produces resistant cysts that can wait out the stressful conditions.)
A: environmental stress occurs

Q: Cysts help protists survive because they ________.
- are extremely hard to crack open (Incorrect. Protist cysts are tough, but not that tough.)
- trigger sexual reproduction, which increases genetic diversity (Incorrect. Cysts are often the products of sexual reproduction in protists, not its trigger.)
- exhibit virtually no metabolism and are therefore in stasis (Correct. Cysts enable protists to wait out environmental stresses.)
A: exhibit virtually no metabolism and are therefore in stasis

Q: ________ are aquatic.
- Approximately half of protists (Incorrect. This is not the correct number of aquatic protists.)
- Very few protists (Incorrect. This is not the correct number of aquatic protists.)
- Most protists (Correct. Most protists exist in some type of aquatic environment, even if it is just damp soil or snow.)
A: Most protists

Q: Excavata protists are characterized by ________.
- the presence of an alveolus (Incorrect. Alveolates are members of the Chromalveolata group of protists.)
- cytoplasmic streaming movement (Incorrect. Cytoplasmic streaming is how Rhizaria move.)
- a feeding groove on one side of their asymmetrical, single-celled body (Correct. Excavata are asymmetric, single-celled organisms with a groove cut from one side of their body where food enters.)
A: a feeding groove on one side of their asymmetrical, single-celled body

Q: ________ lack functional mitochondria.
- Parabasalids (Incorrect. Parabasalids have functional mitochondria.)
- Euglenozoans (Incorrect. Euglenozoans have functional mitochondria.)
- Diplomonads (Correct. Diplomonads posses mitosomes, which are essentially nonfunctional mitochondrial remnant organelles.)
A: Diplomonads

Q: The ________ possess hydrogenosomes, semi-functional mitochondria that actually work anaerobically.
- diplomonads (Incorrect. Diplomonads do not have any functional mitochondria.)
- euglenozoans (Incorrect. The euglenozoans do not possess hydrogenosomes.)
- parabasalids (Correct. The hydrogenosomes in parabasalids function anaerobically and produce hydrogen gas as a byproduct.)
A: parabasalids

Q: The causative agent of African sleeping sickness is a type of ________.
- diplomonad (Incorrect. The diplomonad Giardia lamblia causes intestinal distress.)
- parabasalid (Incorrect. The parabasalid Trichomonas vaginalis causes a sexually transmitted disease, trichamoniasis.)
- euglenozoan (Correct. The euglenozoan Trypanosoma brucei causes African sleeping sickness.)
A: euglenozoan

Q: The ________ ancestor likely resulted from a secondary endosymbiotic event.
- Excavata (Incorrect. Excavata provide no evidence that their ancestor engulfed an already photosynthetic eukaryotic organism.)
- Rhizaria (Incorrect. Rhizaria are heterotrophic protists that do not perform photosynthesis.)
- Chromalveolata (Correct. The chromalveolate ancestor likely engulfed a photosynthetic red algae that had already engulfed a photosynthetic prokaryote.)
A: Chromalveolata

Q: The ________ are chromalveolates characterized by a membrane-bound sac just below the cell membrane that likely functions in osmoregulation.
- bioluminants (Incorrect. While some chromalveolates are bioluminescent, there is not a separate group of bioluminants.)
- stramenopiles (Incorrect. The stramenopiles possess a textured flagellum.)
- alveolates (Correct. These chromalveolates possess an alveolus that may be involved in osmoregulation.)
A: alveolates

Q: The ________ have a fungus-like morphology with extensive filaments for nutrient uptake.
- brown algae (Incorrect. Brown algae are colloquially known as seaweeds and share some resemblance to land plants.)
- diatoms (Incorrect. Diatoms are unicellular protists encased in silicon dioxide glassy cell walls.)
- oomycetes (Correct. The oomycetes heavily resemble fungi though they are not closely related to these organisms.)
A: oomycetes

Q: Rhizaria protists are characterized by ________.
- a feeding groove on one side of their asymmetrical, single-celled body (Incorrect. Excavata are asymmetric, single-celled organisms with a groove cut from one side of their body where food enters.)
- the presence of an alveolus (Incorrect. Alveolates are members of the Chromalveolata group of protists.)
- cytoplasmic streaming movement (Correct. Cytoplasmic streaming is how Rhizaria move.)
A: cytoplasmic streaming movement

Q: The ________ occasionally resemble tiny snails.
- amoebas (Incorrect. On the whole amoebas do not resemble tiny snails.)
- radiolarians (Incorrect. The radiolarians have elaborate exteriors of glassy silica but do not resemble snails.)
- foraminiferans (Correct. Some forams resemble tiny snails with porous shells of calcium carbonate.)
A: foraminiferans

Q: Sedimented radiolarians ________.
- resemble tiny snails with porous shells of calcium carbonate (Incorrect. These are the foraminiferans.)
- have pseudopodia that extend through the pores and allow movement (Incorrect. These are the amoebas.)
- have elaborate exteriors of glassy silica and are very common in the fossil record (Correct. The radiolarians have elaborate exteriors of glassy silica and are very common in the fossil record.)
A: have elaborate exteriors of glassy silica and are very common in the fossil record

Q: Land plants share a common ancestor with the supergroup ________.
- Amoebozoa (Incorrect. The supergroup Amoebozoa do not share a common ancestor with land plants.)
- Opisthokonta (Incorrect. The supergroup Opisthokonta shares a common ancestor with sponges and all animals.)
- Archaeplastida (Correct. The supergroup Archaeplastida, which includes the red and green algae, share a common ancestor with the land plants.)
A: Archaeplastida

Q: The red algae are common in tropical water, and ________.
- typically exist as colonial organisms (Incorrect. Red algae are not colonial organisms.)
- typically exist as large, multinucleate, single cells (Incorrect. Red algae are not multinucleated cells.)
- are typically called “seaweeds” (Correct. The rhodophytes often contain phycoerythrins, red accessory pigments that give them their name; the large multicellular forms are common in tropical waters and are termed seaweed.)
A: are typically called “seaweeds”

Q: Of the algaes, the ________ are the furthest living relatives to land plants.
- charophytes (Incorrect. The green algae are the closest living relatives to land plants.)
- chlorophytes (Incorrect. The green algae are the closest living relatives to land plants.)
- rhodophytes (Correct. The green algae are the closest living relatives to land plants, making the red algae the furthest living relative of the algaes.)
A: rhodophytes

Q: The ________ move using tube-like pseudopodia.
- Archaeplastida (Incorrect. The supergroup Archaeplastida, which includes the red and green algae, share a common ancestor with the land plants but they do not move by psuedopodia.)
- Opisthokonta (Incorrect. The supergroup Opisthokonta moves using a flagellum.)
- Amoebozoa (Correct. The supergroup Amoebozoa move with pseudopodia that extend like tubes or flat lobes, unlike the hair-like pseudopodia of Rhizaria.)
A: Amoebozoa

Q: The ________ exhibit similarities to fungi as a result of convergent evolution.
- amoebozoans (Incorrect. On the whole amoebozoans do not share many features with fungi.)
- rhizarians (Incorrect. Rhizarians do not share morphological features with fungi.)
- slime molds (Correct. Slime molds and fungi share some morphological similarities that are due to these features arising independently in the two lineages.)
A: slime molds

Q: The ________ take on a slug form in times of depleted nutrients.
- plasmodial slime molds (Incorrect. The plasmodial slime molds are always large, multinucleate blob of cells.)
- sporangia slime molds (Incorrect. The sporangia is the fruiting body of a plasmodial slime mold.)
- cellular slime molds (Correct. When food is plentiful, cellular slime molds exist as individual cells. When food is depleted, they form a mass of cells known as a slug.)
A: cellular slime molds

Q: Animals share a common ancestor with the ________.
- Amoebozoa (Incorrect. The supergroup Amoebozoa do not share a common ancestor with animals.)
- Archaeplastida (Incorrect. The supergroup Archaeplastida, which includes the red and green algae, share a common ancestor with the land plants.)
- Opisthokonta (Correct. The supergroup Opisthokonta shares a common ancestor with sponges and all animals.)
A: Opisthokonta

Q: The choanoflagellates are believed to resemble an early common ancestor of ________.
- mosses (Incorrect. Choanoflagellates do not resemble an ancestor of mosses.)
- seaweeds (Incorrect. Choanoflagellates do not resemble an ancestor of seaweeds.)
- sponges (Correct. The contractile collar that surrounds the flagellum in choanoflagellates closely resembles the collar cells in sponges, suggesting a shared history.)
A: sponges

Q: The ________ group contains at least one type of human parasite.
- choanoflagellates (Incorrect. The choanoflagellates are not generally parasitic.)
- LUCA (Incorrect. LUCA stands for Last Universally Common Ancestor, a theoretical (to date) organism that gave rise to all types of life present on Earth today.)
- mesomycetozoans (Correct. The mesomycetozoans are a small group of mostly fish parasites but there is at least one human parasite in the group.)
A: mesomycetozoans

Q: Symbiotic dinoflagellates contribute to ________.
- the digestion of wood by termites (Incorrect. Dinoflagellates do not digest wood for termites.)
- the creation of food sources only for sea-dwelling organisms (Incorrect. This is not the role of symbiotic dinoflagellates in the oceans.)
- coral’s algal pigments (Correct. Without these photosynthetic organisms, corals lose algal pigments, which is the visible sign of coral bleaching.)
A: coral’s algal pigments

Q: ________ contribute to the digestion of wood by termites.
- Aerobic protists (Incorrect. The gut of a termite is not an aerobic environment.)
- Mixotrophic amoebozoans (Incorrect. There are no amoebozoans in the gut of a termite.)
- Anaerobic parabasalids (Correct. These anaerobic protists contribute an essential step in the breakdown of cellulose.)
A: Anaerobic parabasalids

Q: Approximately ________ of the world’s photosynthesis is performed by protists.
- 75 percent (Incorrect. This percentage is too high.)
- 50 percent (Incorrect. This is not the correct percentage.)
- 25 percent (Correct. Dinoflagellates, diatoms, and multicellular algae in particular contribute around 25 percent of the global photosynthesis.)
A: 25 percent

Q: Saprobes are specialized to ________.
- breakdown cellulose (Incorrect. This is not the specialization of saprobes.)
- act as mixotrophs (Incorrect. Saprobes are not generally mixotrophs.)
- absorb nutrients from nonliving organic matter (Correct. Saprobic protists (and fungi and bacteria) return inorganic nutrients to the soil and water, serving the vital role of decomposers.)
A: absorb nutrients from nonliving organic matter

Q: Most ________ are decomposers.
- dinoflagellates (Incorrect. Most dinoflagellates are photosynthetic.)
- amoebas (Incorrect. Most amoebas are heterotrophs.)
- chytrids (Correct. Chytrids are predominantly decomposers; they are actually the reason excess airborne pollen doesn’t overwhelm the environment.)
A: chytrids

Q: The ________ are mostly marine decomposers of dead plant material.
- oomycetes (Incorrect. There are saprobic oomycetes but they are not primarily marine decomposers.)
- mesomycetozoa (Incorrect. These protists are predominantly fish parasites, not decomposers.)
- labyrinthulomycetes (Correct. These single-celled organisms generally live in marine ecosystems where they compose plant tissue.)
A: labyrinthulomycetes

Q: ________ accounts for 50 percent of all malaria cases in humans.
- Phytophthora infestans (Incorrect. This is causative protist for potato late blight.)
- Trypanosoma brucei (Incorrect. This is the causative agent of African sleeping sickness.)
- Plasmodium falciparum (Correct. P. falciparum is the primary cause of malaria-related fatalities in tropical regions of the world.)
A: Plasmodium falciparum

Q: Trypanosoma brucei is the causative agent of ________.
- malaria cases in humans (Incorrect. This is caused by Plasmodium falciparum.)
- potato late blight (Incorrect. This is caused by Phytophthora infestans.)
- African sleeping sickness (Correct. Trypanosoma brucei causes African sleeping sickness.)
A: African sleeping sickness

Q: The famous Irish potato famine of the nineteenth century was due to ________.
- Plasmodium falciparum (Incorrect. P. falciparum is the primary cause of malaria-related fatalities in tropical regions of the world.)
- Trypanosoma brucei (Incorrect. This is the causative agent of African sleeping sickness.)
- Phytophthora infestans (Correct. This is causative protist for potato late blight, which led to the nineteenth century Irish potato famine.)
A: Phytophthora infestans