Deck 27: The Origin and Diversification of Eukaryotes

Question 1

The plasmodial slime molds

A) form a plasmodium that is a coenocyte.
B) lack fruiting bodies.
C) consist of large numbers of myxamoebas.
D) consist at times of a mass called a pseudoplasmodium.
E) possess flagella.

Answer 1

A

Question 2

Which statement about eukaryotic phytoplankton is not true?

A) Some are important primary producers.
B) Some contributed to the formation of petroleum.
C) Some form toxic "red tides."
D) Some are food for marine animals.
E) They constitute a clade.

Answer 2

E

Question 3

Which clade of eukaryotes includes groups that produce chlorophyll a and b?

A) Chromalveolates
B) Plantae
C) Excavates
D) Rhizaria
E) Unikonts

Answer 3

B

Question 4

Microbial eukaryotes with flagella

A) appear in several clades.
B) are all algae.
C) all have pseudopods.
D) are all colonial.
E) are never pathogenic.

Question 5

The evolutionary relationship among the five major groups of protists is

A) uncertain, or at most weakly supported.
B) strongly supported by morphological data.
C) strongly supported by genomic data.
D) Both b and c
E) None of the above

Question 6

The overall size that unicellular microbial eukaryotes can achieve is limited by their

A) energy-producing potential.
B) metabolism.
C) mitochondria.
D) surface area-to-volume ratio.
E) Both a and b

Question 7

Which statement about the brown algae is not true?

A) They are all multicellular.
B) They use the same photosynthetic pigments as do land plants.
C) They are almost exclusively marine.
D) A few are many meters in length.
E) They are stramenopiles.

Question 8

The _______ include the only microbial eukaryotes that contain the full complement of photosynthetic pigments characteristic of plants.

A) choanoflagellates
B) parabasalids
C) cilians
D) red algae
E) chlorophytes

Question 9

Which clade of eukaryotes includes groups that do not have mitochondria?

A) Chromalveolates
B) Plantae
C) Excavates
D) Rhizaria
E) Unikonts

Question 10

The many organisms designated as "protists" or "microbial eukaryotes" are

A) closely related to the bacteria.
B) highly diverse and not necessarily closely related to one another.
C) part of a monophyletic clade.
D) all unicellular.
E) all microscopic.

Question 11

The red algae

A) are mostly unicellular.
B) are mostly marine.
C) owe their red color to a special form of chlorophyll.
D) have flagella on their gametes.
E) are all heterotrophic.

Question 12

Which clade of eukaryotes includes the choano­flagellates, whose bodies resemble cells found in sea sponges?

A) Chromalveolates
B) Plantae
C) Excavates
D) Rhizaria
E) Unikonts

Question 13

The ciliates

A) move by means of short flagella.
B) use amoeboid movement.
C) include Plasmodium, the agent of malaria.
D) possess both a macronucleus and micronuclei.
E) are autotrophic.

Question 14

Apicomplexans

A) possess flagella.
B) possess a glassy shell.
C) are all parasitic.
D) are algae.
E) include the trypanosomes that cause sleeping sickness.

Question 15

Which statement about the chlorophytes is not true?

A) They use the same photosynthetic pigments as do land plants.
B) Some are unicellular.
C) Some are multicellular.
D) All are microscopic in size.
E) They display a great diversity of life cycles.

Question 16

Which of the following was an essential step in the evolution of eukaryotic cells?

A) The development of a flexible cell surface
B) The development of a cytoskeleton
C) The development of a nuclear envelope
D) The endosymbiotic acquisition of certain organelles
E) All of the above

Question 17

Which of the following are not monophyletic?

A) Diplomonads
B) Microbial eukaryotes
C) Animals
D) Red algae
E) Eukarya

Question 18

The cellular slime molds

A) possess apical complexes.
B) lack fruiting bodies.
C) form a plasmodium that is a coenocyte.
D) have haploid myxamoebas.
E) possess flagella.

Question 19

The photosynthetic stramenopiles obtained their chloroplasts, which are surrounded by three membranes, through

A) primary endosymbiosis.
B) secondary endosymbiosis, retaining the chloroplast from a red alga.
C) secondary endosymbiosis, retaining the chloroplast from a chlorophyte.
D) tertiary endosymbiosis.
E) None of the above

Question 20

The chloroplasts of photosynthetic protists

A) are structurally identical.
B) gave rise to mitochondria.
C) are all descended from a once free-living cyanobacterium.
D) all have exactly two surrounding membranes.
E) are all descended from a once free-living red alga.

Question 21

Some algae demonstrate the phenomenon of alternation of generations, by which a multicellular, diploid, spore-producing organism gives rise to a multicellular, haploid, gamete-producing organism. Which of the following statements about alternation of generations is false?

A) The haploid and diploid organisms may or may not differ morphologically.
B) The haploid and diploid organisms differ genetically.
C) Only the haploid organism may also reproduce asexually.
D) Haploid gametes can produce new organisms only by fusing with other gametes.
E) Diploid sporophytes may undergo meiosis to produce haploid spores.

Question 22

The _______, members of the phytoplankton, perform as much photosynthesis as all of Earth's rainforests.

A) radiolarians
B) stramenopiles
C) dinoflagellates
D) diatoms
E) None of the above

Question 23

Paramecia contain two types of nuclei: a large macronucleus and as many as 80 micronuclei. The micronuclei are typical eukaryotic nuclei, essential for genetic recombination. The macronucleus

A) is important in sexual recombination (conjugation).
B) contains several micronuclei.
C) contains many copies of the genetic information.
D) contains DNA that is not transcribed.
E) contains DNA that is transcribed but not translated.

Question 24

Which of the following statements about the diversity of protists is false?

A) Protists are found only in aquatic habitats.
B) Protists have many different metabolic lifestyles.
C) Protists use pseudopods or cilia to locomote.
D) Several groups of protists use contractile vacuoles to rid themselves of excess water.
E) All of the above are true; none is false.

Question 25

Which of the following is a sexual reproductive process common to organisms in the Protista (microbial eukaryotes) group?

A) Binary fission
B) Multiple fission
C) Budding and spore formation
D) Union of gametes
E) All of the above

Question 26

Microbial eukaryotes are found in which of the following habitats?

A) Marine habitats
B) Freshwater aquatic habitats
C) The body fluids of other organisms
D) Damp soil
E) All of the above

Question 27

Paramecia have an elaborate sexual behavior in which they line up against each other and fuse. This is followed by an extensive reorganization and exchange of nuclear material. The entire process is called

A) isogamous reproduction.
B) alternation of generations.
C) sexual reproduction.
D) conjugation.
E) None of the above

Question 28

Which of the following statements about the micronucleus and macronucleus is false?

A) The macronucleus is involved in genetic recombination.
B) The micronucleus is a typical eukaryotic nucleus.
C) Multiple copies of macronuclear genes are commonly found.
D) Transcription and translation involve genes found mostly in the macronucleus.
E) The micronucleus and macronucleus are unique to ciliates.

Question 29

In terms of their nutritional mode, microbial eukaryotes are

A) autotrophs.
B) absorptive heterotrophs.
C) ingestive heterotrophs.
D) Both a and b
E) All of the above

Question 30

Which of the following statements about the process of conjugation is false?

A) Micronuclei disintegrate.
B) Meiosis takes place.
C) It is a reproductive process.
D) Mitosis takes place.
E) It is a sexual process of genetic recombination.

Question 31

Which of the following groups of protists secretes an external "shell" of silica (silicon dioxide)?

A) Paramecium
B) Diatoms
C) Red algae
D) Euglenids
E) Amoebozoans

Question 32

When organic material is digested in a food vacuole, the pH in the vacuole

A) decreases to aid in digestion, and then increases as digestion is completed.
B) increases to aid in digestion, and then decreases as digestion is completed.
C) stays the same during and after digestion.
D) stays the same during digestion, and then increases as digestion is completed.
E) None of the above

Question 33

Some _______ live endosymbiotically with coral and contribute to "coral bleaching"?

A) radiolarians
B) stramenopiles
C) dinoflagellates
D) diatoms
E) None of the above

Question 34

The gametocytes of the malaria-causing organism Plasmodium,

A) develop into merozoites.
B) inhabit the salivary glands of Anopheles mosquitoes.
C) are the infective stage obtained from the insect vector.
D) are found inside red blood cells.
E) give rise to zygotes within the mammalian circulatory system.

Question 35

Two different species of ciliate are placed in a solution with an unknown solute concentration. Ciliate A has a contractile vacuole firing rate of 5 per minute; ciliate B has a contractile vacuole firing rate of 12 per minute. Which of the following is a reasonable conclusion based on these observations?

A) Ciliate A has a greater solute concentration than ciliate B.
B) Ciliate B has a greater solute concentration than ciliate A.
C) The solution has a greater solute concentration than ciliate A.
D) The solution has a greater solute concentration than ciliate B.
E) No conclusions can be made unless we know the solute concentration of the solution.

Question 36

Plasmodium, the organism that causes malaria, is a member of the

A) alveolates.
B) stramenopiles.
C) apicomplexans.
D) choanoflagellates.
E) None of the above

Question 37

Which of the following processes is not part of conjugation in Paramecium?

A) Meiosis
B) Mitosis
C) Cytokinesis
D) Fusion of haploid nuclei
E) Breakdown of some micronuclei

Question 38

In the alternation of generations, the gametophyte generation is _______ and produces _______.

A) haploid; spores
B) haploid; gametes
C) diploid; spores
D) diploid; gametes
E) haploid or diploid; spores

Question 39

Microbial eukaryotes are ecologically and evolutionarily important for many reasons. Which of the following is not true of this group?

A) Multicellular groups evolved from microbial eukaryotes.
B) Photosynthetic microbial eukaryotes play a major role in the energy balance of the living world.
C) None of the microbial eukaryotes are parasites.
D) Saprobic microbial eukaryotes are among the important decomposers and thus play a major role in the nutrient cycles of the living world.
E) Many microbial eukaryotes have highly differentiated bodies, even though they consist of only one cell.

Question 40

Which of the following structures is not associated with movement or feeding in Paramecium?

A) Food vacuole
B) Oral groove
C) Cilium
D) Pseudopod
E) Both b and c

Question 41

Which of the following statements does not apply to diatoms?

A) The cell walls are often impregnated with silicon.
B) During mitosis, the top and bottom of the cell become the tops of the two new cells.
C) Floridean starch is the main photosynthetic storage product.
D) Zygotes are formed by gametes that lack cell walls.
E) They can show bilateral or radial symmetry.

Question 42

Which of the following include species that form large toxic "blooms" in the ocean?

A) Foraminiferans
B) Dinoflagellates
C) Kinetoplastids
D) Paramecium
E) Euglena

Question 43

The presence of _______ in the chloroplasts of red algae gives them their characteristic color.

A) phycoerythrin
B) fucoxanthin
C) $\beta$ -carotene
D) chrysolaminarin
E) chlorophyll b

Question 44

A haplontic life cycle includes _______ individuals that form gametes.

A) multicellular haploid
B) multicellular diploid
C) unicellular haploid
D) unicellular diploid
E) None of the above

Question 45

In species that are anisogamous,

A) both male and female gametes are very large.
B) both male and female gametes are microscopic in size.
C) male and female gametes are the same size.
D) male gametes are larger than female gametes.
E) female gametes are larger than male gametes.

Question 46

The common sea lettuce, Ulva lactuca, is said to have an isomorphic life cycle. Which of the following statements about this species is true?

A) The sporophyte and the gametophyte look virtually identical.
B) The diploid and haploid stages of the life cycle are morphologically different from each other.
C) The male and female gametes are different sizes.
D) All of the above
E) None of the above

Question 47

Which of the following characteristics represents the synapomorphy of the alveolates?

A) The presence of peptidoglycan between membranes of an important organelle
B) Rows of tubular hairs on the longer of two unequally sized flagella
C) Air sacs below the plasma membrane
D) A fully parasitic lifestyle
E) External shells of calcium carbonate

Question 48

Which of the following groups may not be monophyletic?

A) Opisthokonts
B) Plantae
C) Chromalveolates
D) Stramenopiles
E) Excavates

Question 49

The algal microbial eukaryote groups differ from one another in terms of their

A) principal photosynthetic storage product.
B) body plan (unicellular or multicellular).
C) lack of or possession of flagella.
D) principal photosynthetic pigments.
E) All of the above

Question 50

Which of the following groups contains multicellular brown algae and giant kelps?

A) Diplomonads
B) Chlorophytes
C) Stramenopiles
D) Alveolates
E) Euglenozoans

Question 51

Perhaps the best-known _______ are the malarial parasites of the genus Plasmodium.

A) turbellarians
B) mastigophorans
C) dinoflagellates
D) apicomplexans
E) poriferans

Question 52

Which of the following represents the synapomorphy of the stramenopiles?

A) The presence of peptidoglycan between membranes of an important organelle
B) Rows of tubular hairs on the longer of two unequally sized flagella
C) Air sacs below the plasma membrane
D) A fully parasitic lifestyle
E) External shells of calcium carbonate

Question 53

A eukaryotic organism that undergoes alternation of generations in which different generations do not resemble each other morphologically is referred to as

A) homomorphic.
B) heteromorphic.
C) isomorphic.
D) anisomorphic.
E) gametophytic.

Question 54

Algal life cycles show extreme variation. Members of only one group, the _______, do not have flagellated motile cells in at least one of the stages.

A) alveolates
B) red algae
C) euglenozoans
D) diplomonads
E) ciliates

Question 55

Which of the following statements about the life cycle of the green alga Ulva is false?

A) Ulva has an isomorphic life cycle.
B) The sporophyte and gametophyte can be differentiated only microscopically.
C) All species of Ulva are isogamous.
D) Individual gametophytes produce only sperm or only eggs-never both.
E) The diploid sporophyte produces flagellated spores.

Question 56

Which of the following groups includes the dinoflagellates?

A) Alveolates
B) Green algae
C) Red algae
D) Stramenopiles
E) Euglenozoans

Question 57

Some oomycetes are coenocytes, which means that

A) they have a single nucleus enclosed in a single plasma membrane.
B) their cytoplasm is pigmented.
C) they have multiple nuclei enclosed in a single plasma membrane.
D) their reproductive cells have no flagella.
E) they have multiple flagella on their nonreproductive cells.

Question 58

Which of the following is not a characteristic of the brown algae?

A) Leaflike growths called thalli
B) Storage of the products of photosynthesis as floridean starch
C) A specialized holdfast that aids in attachment to a surface
D) The presence of the carotenoid fucoxanthin in their chloroplasts
E) Multicellularity

Question 59

The _______ include the water molds and their terrestrial relatives, such as the downy mildews.

A) parabasalids
B) apicomplexans
C) red algae
D) euglenoids
E) oomycetes

Question 60

Dinoflagellates are common endosymbionts of

A) coral.
B) fungi.
C) other dinoflagellates.
D) tertiary endosymbionts.
E) None of the above

Question 61

The condition of different organisms living together, one inside the other, is called _______.

Question 62

When some autotrophic Euglena are placed in the dark, they

A) stop producing their photosynthetic pigment.
B) produce an excess of photosynthetic pigment.
C) begin feeding on organic material floating in the surrounding water.
D) die.
E) Both a and c

Question 63

Sea lettuce, Ulva lactuca, is a member of the green algae clade of

A) charophytes.
B) glaucophytes.
C) coenocytes.
D) chlorophytes.
E) None of the above

Question 64

Which of the following organisms lack mitochondria?

A) Diplomonads
B) Choanoflagellates
C) Red algae
D) Euglenozoans
E) Both b and c

Question 65

Which of the following diseases is not caused by the trypanosomes?

A) African sleeping sickness
B) Malaria
C) Leishmaniasis
D) Chagas' disease
E) None of the above; all of these diseases are caused by trypanosomes.

Question 66

Members of which group are thought to be the closest relatives of the animals?

A) Euglenozoans
B) Choanoflagellates
C) Stramenopiles
D) Alveolates
E) Chlorophytes

Question 67

_______ have created vast limestone deposits throughout the world.

A) Radiolarians
B) Dinoflagellates
C) Foraminiferans
D) Heliozoans
E) None of the above

Question 68

Which of the following events is not normally associated with the life cycle of a plasmodial slime mold?

A) Development of spores into myxamoebas
B) Formation of a sclerotium when conditions are adverse
C) Active feeding by the plasmodium as it engulfs food particles
D) Meiosis to form sporangiophores
E) Fusion of swarm cells to form a diploid zygote

Question 69

The _______ are marine microbial eukaryotes that secrete a glassy endoskeleton.

A) algae
B) protozoa
C) radiolarians
D) flagellates
E) dinoflagellates

Question 70

The _______ are a group of protists that harbor photosynthetic endosymbionts that make them look greenish or golden in color.

A) dinoflagellates
B) plasmodial slime molds
C) radiolarians
D) diatoms
E) corals

Question 71

Which of the following features is not a characteristic of the plasmodium of an acellular slime mold?

A) Many nuclei enclosed in a single plasma membrane (coenocyte)
B) Haploid nuclei
C) Cytoplasmic streaming
D) Mitosis without cytokinesis
E) Formation of a sclerotium when conditions are unfavorable

Question 72

All eukaryotes that are not plants, fungi, or animals have traditionally been called _______.

Question 73

In the cellular slime molds, the onset of adverse conditions causes

A) aggregation of swarm cells to form a plasmodium.
B) formation of sporangia.
C) release of myxamoebas from fruiting bodies.
D) the onset of cytoplasmic streaming.
E) aggregation of myxamoebas to form a slug or pseudoplasmodium.

Question 74

The signal responsible for the aggregation of myxamoebas is

A) the onset of adverse conditions.
B) alginic acid.
C) phycoerythrin.
D) actin.
E) None of the above

Question 75

The microbial eukaryotes that are responsible for sleeping sickness and those that are responsible for malaria

A) are both alveolates.
B) both have insect vectors for transmission to humans.
C) cause the same symptoms.
D) both have gametocyte life stages.
E) All of the above

Question 76

Which of the following organisms are not considered microbial eukaryotes?

A) Diatoms
B) Algae
C) Slime molds
D) Sponges
E) Giant kelp

Question 77

Which of the following are not unikonts?

A) Fungi
B) Algae
C) Animals
D) Choanoflagellates
E) Slime molds

Question 78

The difference between acellular slime molds and cellular slime molds is that

A) only cellular slime molds are motile.
B) they have different numbers of nuclei within the plasma membrane.
C) only acellular slime molds ingest food by endocytosis.
D) only cellular slime molds ingest food by endocytosis.
E) acellular slime molds prefer cool, moist habitats, whereas cellular slime molds prefer dry, hot conditions.

Question 79

_______ are specialized vesicles that excrete the excess water taken in by some microbial eukaryotes.

Question 80

Which of the following groups uses pseudopods for locomotion?

A) Radiolarians
B) Amoebozoans
C) Euglenids
D) Both a and b
E) Both a and c