Deck 26: The Origin and Diversification of Eukaryotes

Question 1

Ability of protists to increase their surface area for gas and nutrient exchange is conferred by

A) mitochondria. b. a cytoskeleton.
C) a nucleus.
D) a cell wall.
E) a flexible cell membrane.

Answer 1

E

Question 2

The chloroplast of red algae retains certain pigments of the original cyanobacterial endosymbiont that are absent in the chloroplasts of green algae.The evolutionary significance of this is that

A) red algae cannot photosynthesize, leading to heterotrophy. b. neither green algae nor red algae can be classified as protists.
C) chloroplasts originated as free-living prokaryotes.
D) red algae are cyanobacteria.
E) red algae are prokaryotes.

Answer 2

C

Question 3

Which of the following are not monophyletic?

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

Answer 3

B

Question 4

Refer to the figure, which shows endosymbiotic events in the evolution of chloroplasts. After millions of generations, the events in part A of the figure led to which of the following?

A) The DNA of the host cell replaced all prokaryotic DNA in the chloroplast.
B) The chloroplast retained prokaryotic DNA that codes for proteins in the chloroplast.
C) The DNA of the host cell moved to the nucleus of the engulfed cell.
D) The chloroplast lost its entire prokaryotic DNA, which was replaced with DNA from the host cell.
E) The chloroplast retained its ability to survive outside of the host.

Question 5

The overall size of unicellular microbial eukaryotes is limited by their

A) energy-producing potential.
B) nuclear volume.
C) mitochondria.
D) surface area-to-volume ratio.
E) chloroplasts.

Question 6

What feature of eukaryotes makes endosymbiosis possible?

A) Nuclear membrane
B) Mitochondria
C) Flexible cell membrane
D) Digestive vacuoles
E) Flagella

Question 7

The many organisms designated as protists are

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

Question 8

The increasing concentration of atmospheric oxygen in Earth's early atmosphere

A) was favorable to most prokaryotes because of their small size.
B) was fatal to numerous eukaryotes because they possessed mitochondria
C) conferred a selective advantage to a eukaryote that possessed a mitochondrion.
D) conferred a selective advantage to a eukaryote that possessed a chloroplast.
E) conferred a selective advantage to prokaryotes because of their stiff membranes.

Question 9

Which type of unicellular organism would benefit most from having a flexible cell surface?

A) A small prokaryote that obtains energy through photosynthesis
B) A small archaeal organism that obtains energy heterotrophically
C) An organism with a rigid cell wall
D) An organism that moves using flagella
E) A larger organism that obtains energy through phagocytosis

Question 10

Refer to the figure, which shows endosymbiotic events in the evolution of chloroplasts. Which statement concerning the events shown in part B of the figure is false?

A) The engulfed cell possessed DNA prior to the endosymbiosis.
B) The engulfing cell possessed DNA prior to the endosymbiosis.
C) The engulfed cell was photosynthetic.
D) The engulfed cell was a prokaryote.
E) The events required a flexible cell membrane in the engulfing cell.

Question 11

Which of the following allowed for an increase in surface area relative to volume in eukaryotic cells?

A) The development of ribosome-studded internal membranes
B) The nuclear membrane
C) The digestive vacuole
D) A flexible cell membrane
E) A more complex cytoskeleton

Question 12

What evidence exists that the glaucophytes are one of the earliest groups to branch off from eukaryotes following the primary endosymbiosis of a cyanobacterium?

A) Remnants of the peptidoglycan-containing cell wall of the cyanobacterium can be found between membrane layers of the chloroplast.
B) Their chloroplasts contain the same pigments as those of early land plants and green algae.
C) There are three membranes that surround the chloroplast.
D) The glaucophyte chloroplast has retained some of the DNA and rRNA genes from its cyanobacterial ancestor.
E) A vestigial nucleus from the cyanobacterial ancestor is present in the chloroplast.

Question 13

The chloroplasts of red algae have a characteristic color because the red algae

A) obtained their chloroplast by secondary endosymbiosis.
B) retain certain pigments from the original prokaryote symbiont lost in green algae and plants.
C) acquired red pigments from a red tide.
D) have a peptidoglycan-containing cell wall.
E) have a thick cell wall that refracts the chlorophyll color.

Question 14

Which characteristic of eukaryotes is not related to the presence of flexible cell membranes?

A) A nuclear membrane
B) Endosymbiosis of mitochondria
C) Endocytosis
D) Phagocytosis
E) Free ribosomes

Question 15

The occurrence of primary endosymbiosis in the evolutionary past is supported by the existence of

A) three membranes surrounding all chloroplasts.
B) three membranes surrounding all mitochondria.
C) peptidoglycan between the inner and outer membrane walls of chloroplasts.
D) two membranes surrounding the nucleus.
E) flagella consisting of microtubules.

Question 16

Which of the following was not an early step in the evolution of eukaryotic cells?

A) Development of a flexible cell surface
B) Development of a cytoskeleton
C) Development of a nuclear envelope
D) Endosymbiotic acquisition of certain organelles
E) Development of ribosomes

Question 17

A prokaryotic cell with a rigid cell wall is limited in how large it can grow.A eukaryotic cell, with a flexible cell membrane, is able to grow much larger.The primary reason for this is that

A) the flexible cell membrane in a eukaryotic cell allows for infolding, increasing surface area.
B) there are no surface area-to-volume constraints on a eukaryotic cell.
C) eukaryotic cells have mitochondria, which require the cell to be larger.
D) eukaryotic cells have a cytoskeleton, which allows for a smaller surface area-to-volume ratio.
E) eukaryotic cells must to be large to accommodate food vacuoles.

Question 18

Prokaryotes do not obtain organelles by endosymbiosis, because they lack

A) a flexible cell membrane.
B) DNA.
C) flagella.
D) digestive vacuoles.
E) the ability to photosynthesize.

Question 19

The ancestor of photosynthetic euglenids took up the chloroplast of a green alga.This explains why photosynthetic euglenids

A) have a flagellum.
B) have the same photosynthetic pigments as plants.
C) are ancestral to land plants.
D) have two nuclei.
E) lose their photosynthetic pigments when kept in the dark.

Question 20

As cyanobacterial populations boomed, the process of photosynthesis generated significant levels of O₂ in the oceans and atmosphere.Which statement accurately describes conditions surrounding the evolution of eukaryotes and the early role of the proteobacterial endosymbiont that would eventually develop into a mitochondrion?

A) The increase in O₂ resulted in an increase in the energy required to maintain the eukaryotic cell—the phagocytosis of a proteobacterium was originally intended as a form of food storage.
B) The increase in O₂ resulted in a population boom for eukaryotes—those that enlisted the aid of a proteobacterial endosymbiont were more likely to find food sources than those that did not.
C) The increase in O₂ had a reducing effect on most eukaryotes, and the acquisition of a proteobacterium that could reduce this O₂ into water allowed the eukaryotic host to survive.
D) The increase in O₂ had did not have an effect on most eukaryotes, but the acquisition of a proteobacterium that coupled O₂ reduction with ATP production provided an additional source of energy to the eukaryotic host.
E) The increase in O₂ had an oxidizing effect on most eukaryotes, and the acquisition of a proteobacterium that could reduce this O₂ into water allowed the eukaryotic host to survive.

Question 21

Photosynthetic eukaryotes have genes for rRNA in their nuclei, mitochondria, and chloroplasts.Based on what you know about the origins of mitochondria and chloroplasts, which of the statements below would best describe the evolutionary relationship between the rRNA genes found in these three organelles?

A) Nuclear and mitochondrial rRNA are derived from close relatives; however, both are distant from chloroplast rRNA.
B) Mitochondrial and chloroplast rRNA are derived from close relatives; however, both are distant from nuclear rRNA.
C) Nuclear and chloroplast rRNA are derived from close relatives; however, both are distant from mitochondrial rRNA.
D) Mitochondrial, chloroplast, and nuclear rRNA are all derived from distant relatives.
E) There is no reason to assume that any of the three rRNA genes are similar to closely or distantly related relatives.

Question 22

Which group contains multicellular brown algae and giant kelps?

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

Question 23

Which statement about protists is false?

A) Most protists are found in terrestrial habitats.
B) Protists have many different metabolic lifestyles.
C) Protists use pseudopods, cilia, or flagella for locomotion.
D) Several groups of protists use contractile vacuoles to rid themselves of excess water.
E) Many protists are photosynthetic.

Question 24

Alveolates typically

A) have two unequal flagella, one of which has hairs.
B) possess long, thin pseudopods.
C) have lobe-shaped pseudopods.
D) possess sacs just beneath their plasma membranes.
E) lack mitochondria.

Question 25

Which group can produce a toxin in marine environments that accumulates in clams, mussels, and oysters and can cause paralytic shellfish poisoning?

A) Red algae
B) Radiolarians
C) Diatoms
D) Euglenids
E) Dinoflagellates

Question 26

Plasmodium, the organism that causes malaria, has a mass of organelles at the tip of the cell that enables it to enter cells in the human body.This characteristic suggests that Plasmodium is a member of the

A) alveolates.
B) stramenopiles.
C) apicomplexans.
D) choanoflagellates.
E) rhizarians.

Question 27

When ancestral photosynthetic euglenids obtained their chloroplasts, the result was a chloroplast surrounded by three membranes.This is evidence of acquisition of the chloroplast by

A) primary endosymbiosis.
B) secondary endosymbiosis, retaining the chloroplast from a green alga.
C) secondary endosymbiosis, retaining the chloroplast from a plant.
D) tertiary endosymbiosis.
E) quaternary endosymbiosis.

Question 28

Dinoflagellates are common endosymbionts of

A) coral.
B) fungi.
C) other dinoflagellates.
D) tertiary endosymbionts.
E) stramenopiles.

Question 29

Which diseases are caused by apicomplexans?

A) Giardiasis and toxoplasmosis
B) Malaria and giardiasis
C) A human sexually transmitted disease and toxoplasmosis
D) Malaria and a human sexually transmitted disease
E) Malaria and toxoplasmosis

Question 30

Refer to the diagram, which shows the role of vacuoles in ciliate digestion. The figure illustrates an experiment designed to determine whether Paramecium digests food in an acidic environment.This organism most likely _______ and is _______.

A) is free-swimming with cilia; heterotrophic
B) is free-swimming with flagella; heterotrophic
C) is free-swimming with flagella; autotrophic
D) moves by floating in plankton; autotrophic
E) is free-swimming with cilia; autotrophic

Question 31

What would be a plausible outcome if cats developed a resistance to Toxoplasma?

A) Cats would no longer display a fear of dogs, because Toxoplasma would be unable to complete its life cycle and infect new cats.
B) Cats would remain afraid of dogs, because Toxoplasma would be unable to complete its life cycle and infect new cats.
C) Rats would no longer display a fear of cats, because Toxoplasma would be unable to complete its life cycle and infect new rats.
D) Rats would remain afraid of cats, because Toxoplasma would be unable to complete its life cycle and infect new rats.
E) There would be no change in the behavior of infected rats or cats.

Question 32

Which of the following represents the synapomorphy of the stramenopiles?

A) The presence of peptidoglycan between membranes of a chloroplast
B) Rows of tubular hairs on the longer of two flagella of unequal size
C) Air sacs below the plasma membrane
D) A fully parasitic lifestyle
E) External shells of calcium carbonate

Question 33

Which statement does not apply to apicomplexans?

A) They are parasites.
B) They have complex life cycles.
C) They lack contractile vacuoles.
D) Each has an apical mass of organelles that helps it enter hosts.
E) Each possesses small sacs just below its cell membrane.

Question 34

Which statement about microbial eukaryotes is false?

A) Multicellular groups evolved from microbial eukaryotes.
B) Photosynthetic microbial eukaryotes play a major role in the energy balance of the living world.
C) There are no parasitic forms of microbial eukaryotes.
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 35

Dinoflagellates possess sacs beneath their plasma membranes and chloroplasts that contain pigments that give them a golden brown color.Dinoflagellates are therefore classified as

A) stramenopiles.
B) green algae.
C) red algae.
D) alveolates.
E) euglenids.

Question 36

You are watching a Paramecium in fresh water and see a rounded structure within it enlarge and then suddenly contract as water is expelled.You have just witnessed the

A) food vacuole releasing excess water acquired through eating.
B) oral groove expelling water as food is ingested.
C) result of ciliary action involved in locomotion.
D) contractile vacuole keeping the organism's cytoplasm hypertonic to the environment.
E) expulsion of waste produced during digestion.

Question 37

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) increases or decreases depending on the material consumed.

Question 38

Refer to the figure. This phylogenetic tree shows one current hypothesis and estimated time line for the origin of the major groups of eukaryotes.Which clade of eukaryotes was the first to diverge from other eukaryotes?

A) Alveolates
B) Rhizarians
C) Excavates
D) Amoebozoans
E) Plantae

Question 39

Many dinoflagellates are _______ that have _______.Most live in _______.

A) ciliates; chloroplasts; the oceans
B) endosymbionts; two flagella; the oceans
C) stramenopiles; two flagella; rivers
D) endosymbionts; cilia; rivers
E) endosymbionts; two flagella; rivers

Question 40

Refer to the diagram, which shows the role of vacuoles in ciliate digestion. Which of the following is a plausible hypothesis to explain why the vacuole color returns to red?

A) The pH returns to basic because of increasing proton concentration.
B) The pH returns to basic because of decreasing proton concentration.
C) The dye from all food vacuoles coalesces into one vesicle destined for exocytosis.
D) Multiple food vacuoles at different stages of digestion fuse into a single vesicle.
E) The pH returns to acidic because of an increase in salt concentration.

Question 41

Which statement about oomycetes (water molds) is true and also explains why they are classified as protists and not fungi?

A) They are filamentous and stationary.
B) They secrete enzymes that digest large food molecules into smaller molecules that they can absorb.
C) Their cell walls are made of cellulose.
D) Their cell walls are made of chitin.
E) They often produce a whitish, cottony mold that grows on dead fish.

Question 42

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

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

Question 43

Which statement about diatoms is false?

A) They have shells made of calcium carbonate.
B) They are responsible for about one-fifth of the photosynthetic carbon fixation on Earth.
C) They are one of several types of marine phytoplankton.
D) They store oil for energy and flotation.
E) Their male gametes have flagella.

Question 44

The elimination of _______ would result in the greatest decrease in global oxygen levels.

A) radiolarians
B) stramenopiles
C) cercozoans
D) diatoms
E) foraminiferans

Question 45

Which of the following are protists that do not use photosynthesis?

A) Dinoflagellates
B) Algae
C) Plants
D) Slime molds
E) Euglenids

Question 46

While out hiking, you drink water from a stream.Several days later you feel sick with diarrhea and intestinal bloating.Your doctor collects a stool sample and finds unicellular organisms that lack mitochondria and have multiple flagella.You are most likely infected with

A) slime molds.
B) the diplomonad Giardia.
C) kinetoplastid trypanosomes.
D) the ciliate Paramecium.
E) testate amoebozoans.

Question 47

If you were to examine limestone deposits throughout the world, which group of organisms would you expect to find in the greatest abundance?

A) Radiolarians
B) Dinoflagellates
C) Foraminiferans
D) Heliozoans
E) Oomycetes

Question 48

Refer to the figure. Which statement about the eukaryotes shown is true?

A) They are specialized to withstand pounding by surf.
B) Their color results from a symbiotic relationship with dinoflagellates.
C) Their fossilized remains make a major contribution to limestone.
D) Their fronds are stiffened with silica.
E) Their primary habitat is above the tidal zone on the seashore.

Question 49

You are examining a sample of salt water and see a single-celled organism with a cell wall constructed of two pieces.The top piece overlaps the bottom piece.The cell wall is impregnated with silica and has an intricate pattern.You are most likely looking at a

A) red alga.
B) radiolarian.
C) diatom.
D) euglenid.
E) dinoflagellate.

Question 50

Refer to the figure. What are the organisms shown in the figure?

A) Diatoms
B) Radiolarians
C) Euglenids
D) Foraminiferans
E) Apicomplexans

Question 51

Which of the following are protists harboring endosymbionts that produce a greenish or gold color in the host?

A) Euglenids
B) Ciliates
C) Diatoms
D) Amoebas
E) Radiolarians

Question 52

Which statement about brown algae is false?

A) One genus floats in mats in the mid-Atlantic Sargasso Sea.
B) Silica-impregnated cell walls produce intricate patterns unique to each species.
C) A specialized holdfast aids in attachment to a surface.
D) Their chloroplasts contain the carotenoid fucoxanthin.
E) They are multicellular.

Question 53

Refer to the figure. The organisms shown most likely obtain nutrients by _______, and their movement most likely consists of _______.

A) engulfing bacteria; free swimming using flagella
B) photosynthesis; free swimming with cilia
C) photosynthesis; floating in plankton
D) engulfing bacteria; floating in plankton
E) photosynthesis; free swimming using flagella

Question 54

Which protist group includes species that are photosynthetic, multicellular, and many meters long?

A) Alveolates
B) Excavates
C) Stramenopiles
D) Rhizarians
E) Amoebozoans

Question 55

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

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

Question 56

You find a fish carcass in a pond with white filaments radiating from it.Back in the lab, you stain the white filaments and observe that their cell walls are made of cellulose.The species you have found would most likely be classified within the

A) rhizarians.
B) apicomplexans.
C) red algae.
D) euglenids.
E) oomycetes.

Question 57

Refer to the figure. Which statement about the eukaryotes shown is false?

A) They produce a substance used as an emulsifier in ice cream.
B) They are almost exclusively marine organisms.
C) Some forms are found in the Sargasso Sea.
D) They are members of Plantae.
E) They are photosynthetic.

Question 58

The excavates constitute a clade of eukaryotes that includes groups without mitochondria.Which of the following is the most convincing evidence that this absence of mitochondria is a derived condition resulting from a secondary loss?

A) There is a nuclear membrane in these organisms.
B) The cell membrane of these organisms is flexible and capable of phagocytosis.
C) Some of the nuclear genes of these organisms are normally associated with mitochondria.
D) In euglenids, a group in this clade with mitochondria, the mitochondria have distinctive disc-shaped cristae.
E) Other eukaryote clades have both chloroplasts and mitochondria.

Question 59

How might someone distinguish between diplomonads and parabasalids?

A) Diplomonads possess mitochondria, while parabasalids do not.
B) Parabasalids use undulating membranes for locomotion, while diplomonads use only flagella.
C) Only parabasalids have a parasitic lifestyle.
D) Diplomonads are excavates, while parabasalids are not.
E) Parabasalids possess chloroplasts, while diplomonads do not.

Question 60

Which of the following organisms lack mitochondria?

A) Diplomonads
B) Choanoflagellates
C) Red algae
D) Euglenids
E) Foraminiferans

Question 61

If an autotrophic Euglena species in pond water were placed in the dark, it would most likely

A) stop using its chloroplasts to synthesize organic compounds.
B) produce an excess of photosynthetic pigment.
C) begin using its chloroplast to synthesize organic compounds.
D) digest its chloroplast to obtain energy.
E) die.

Question 62

Which statement about the process of conjugation is false?

A) The disintegration of micronuclei is part of the process.
B) Meiosis takes place.
C) It is a reproductive process.
D) Mitosis takes place.
E) It is a sexual process of genetic recombination.

Question 63

Which group uses lobe-shaped pseudopods for locomotion?

A) Amoebozoans
B) Radiolarians
C) Euglenids
D) Foraminiferans
E) Ciliates

Question 64

A Paramecium individual contains two types of nuclei: a large macronucleus and as many as 80 micronuclei.The micronuclei are typical eukaryotic nuclei and are essential for genetic recombination.The macronucleus

A) is important in sexual recombination (conjugation).
B) contains many copies of the genetic information.
C) contains genetic information not found in the micronuclei.
D) contains DNA, but none of this DNA is transcribed.
E) contains DNA that is transcribed, but none of the transcripts are translated.

Question 65

After a particularly warm and wet summer, there is a spike in the population of tsetse flies in a rural sub-Saharan village.Many of the inhabitants begin to complain of fever and aching muscles.What might be the cause of their suffering?

A) The increase in tsetse flies has created more insect vectors for the kinetoplastid Trypanosoma brucei, resulting in more individuals struck by the sleeping sickness.
B) An increase in Trypanosoma brucei has provided the tsetse fly with an additional food supply, and the flies are now able to multiply more rapidly and bite more individuals.
C) Tsetse flies thrive on blood meals; their increase is a result of feeding on immunocompromised individuals.
D) Tsetse fly larvae attract water molds, resulting in contamination of the water supply and subsequent infection of humans by oomycete pathogens.
E) None of the above; the presence of the kinetoplastid Trypanosoma brucei is not related to the increase in the number of people suffering from the symptoms described.

Question 66

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

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

Question 67

Refer to the figure, which shows genetic recombination by conjugation in paramecia. As it is shown in the figure, which statement about the conjugation process in paramecia is true?

A) The two resulting paramecia are genetically different from the original.
B) The two resulting paramecia are genetically identical to the original.
C) Conjugation is a form of asexual reproduction.
D) The two resulting paramecia are genetically different from each other.
E) There is an unequal exchange of DNA between the paramecia.

Question 68

_______ are small _______ that use pseudopods to engulf small organisms and particles of organic matter.Some live in secreted shells (tests) or casings from sand particles glued together.

A) Cercozoans; rhizarians
B) Diatoms; stramenopiles
C) Dinoflagellates; alveolates
D) Loboseans; amoebozoans
E) Euglenids; excavates

Question 69

Which process is not part of conjugation in Paramecium?

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

Question 70

Which of the following is not an asexual reproductive process among microbial eukaryotes?

A) Binary fission
B) Multiple fission
C) Budding
D) Spore formation
E) Meiosis

Question 71

Which statement concerning the spore-bearing fruiting structures produced by plasmodial slime molds is true?

A) Individual myxamoebas disperse
B) They contain diploid nuclei.
C) Their development is prompted by favorable conditions of moisture and food supply.
D) Knobs called sporangia develop at the end of the stalk of the fruiting structure.
E) The spores become diploid swarm cells that move by means of cilia.

Question 72

Which statement 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 73

Which protist group includes large multinucleate terrestrial heterotrophs that are visible to the naked eye and can be several yards in diameter?

A) Ciliates
B) Euglenids
C) Brown algae
D) Foraminiferans
E) Plasmodial slime molds

Question 74

Which statement that does not describe a form of asexual reproduction found in protists.

A) Plasmodium sporozoites give rise to merozoites in the liver cells of humans.
B) Conjugation between two paramecia produces individuals that are genetically distinct from the original organisms.
C) Two daughter diatoms of dissimilar sizes (one smaller than the original) are produced during reproduction.
D) Myxamoebas cycle through slug and spore stages to produce new myxamoebas.
E) Euglenids produce new individuals primarily through binary fission.

Question 75

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) cloning.
B) alternation of generations.
C) sexual reproduction.
D) conjugation.
E) binary fission.

Question 76

Refer to the figure, which shows genetic recombination by conjugation in paramecia. As it is shown in the figure, which statement about the conjugation process in paramecia is false?

A) The macronuclei in the resulting paramecia are genetically different from the macronuclei in the original paramecia.
B) The micronuclei that are exchanged are genetically different from each other.
C) Within each individual, the original macronucleus is destroyed.
D) The two resulting paramecia have a new combination of alleles that is different from the original.
E) The two resulting paramecia are genetically distinct from each other.

Question 77

Which statement regarding the role of meiosis in plasmodial slime molds is true?

A) Meiosis gives rise to the haploid nuclei that accumulate during the vegetative state of the slime mold.
B) During unfavorable conditions, plasmodial nuclei undergo meiosis before the organism creates a resting structure in the form of an irregular mass of hardened cell-like components.
C) During unfavorable conditions, plasmodial nuclei undergo meiosis before the sporangia develop on the fruiting structure.
D) The swarm cells of plasmodial slime molds divide by meiosis to produce haploid gametes.
E) Nuclei of plasmodial slime mold zygotes divide by meiosis to generate new coenocytic organisms.

Question 78

Which term refers to a eukaryotic organism that undergoes alternation of generations in which different generations do not resemble each other morphologically?

A) Homomorphic
B) Heteromorphic
C) Isomorphic
D) Anisomorphic
E) Gametophytic

Question 79

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

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

Question 80

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

A) Development of spores into myxamoebas
B) Formation of an irregular mass when conditions are adverse
C) Active feeding by the plasmodium as it engulfs food particles
D) Production of sporangia through meiosis
E) Fusion of swarm cells to form a diploid zygote