Question 1

According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?

Accepted Answer

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 
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

Question 2

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?

Accepted Answer

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. 
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

Question 3

You are given five test tubes, each containing an unknown protist, and your task is to read the following description and match these five protists to the correct test tube.
In test tube 1, you observe an organism feeding. Your sketch of the organism looks very similar to Figure 28.1. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 2 and 3. Chemical analysis of test tube 3 indicates the presence of substantial amounts of silica. Chemical analysis of test tube 2 indicates the presence of a chemical that is toxic to fish and humans. Microscopic analysis of organisms in test tubes 2, 4, and 5 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 4 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 5 reveals the presence of one large nucleus and several small nuclei in each organism.
   
Figure 28.1
-Test tube 2 contains

Accepted Answer

A)  Paramecium. 
B)  Navicula (diatom). 
C)  Pfiesteria (dinoflagellate). 
D)  Entamoeba. 
E)  Plasmodium. 
A)  Paramecium. 
B)  Navicula (diatom). 
C)  Pfiesteria (dinoflagellate). 
D)  Entamoeba. 
E)  Plasmodium. C

Question 4

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of the white blood cells of animals (monocytes). If one were to erect a taxon that included all organisms that have cells with pseudopods, what would be true of such a taxon?

Accepted Answer

A)  It would be polyphyletic. 
B)  It would be paraphyletic. 
C)  It would be monophyletic. 
D)  It would include all eukaryotes. 
A)  It would be polyphyletic. 
B)  It would be paraphyletic. 
C)  It would be monophyletic. 
D)  It would include all eukaryotes.

Question 5

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

Accepted Answer

A)  thalli 
B)  bladders 
C)  holdfasts 
D)  gel-forming polysaccharides 
A)  thalli 
B)  bladders 
C)  holdfasts 
D)  gel-forming polysaccharides

Question 6

What must occur for asexual reproduction to be successful in P. chromatophora?
1)mitosis
2)S phase
3)meiosis
4)equal distribution of cyanelles during cytokinesis

Accepted Answer

A)  1 only 
B)  1 and 2 
C)  1, 2, and 3 
D)  1, 2, and 4 
E)  2, 3, and 4 
A)  1 only 
B)  1 and 2 
C)  1, 2, and 3 
D)  1, 2, and 4 
E)  2, 3, and 4

Question 7

Which of the following are actual mutualistic partnerships that involve a protist and a host organism?

Accepted Answer

A)  cellulose-digesting gut protists-wood-eating termites 
B)  dinoflagellates-reef-building coral animals 
C)  Trichomonas-humans 
D)  algae-certain foraminiferans 
E)  all except that involving humans 
A)  cellulose-digesting gut protists-wood-eating termites 
B)  dinoflagellates-reef-building coral animals 
C)  Trichomonas-humans 
D)  algae-certain foraminiferans 
E)  all except that involving humans

Question 8

Green algae differ from land plants in that many green algae

Accepted Answer

A)  are heterotrophs. 
B)  are unicellular. 
C)  have plastids. 
D)  have alternation of generations. 
E)  have cell walls containing cellulose. 
A)  are heterotrophs. 
B)  are unicellular. 
C)  have plastids. 
D)  have alternation of generations. 
E)  have cell walls containing cellulose.

Question 9

A crucial photosynthetic gene of the cyanobacterium that gave rise to the cyanelle is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the cyanelle. This is evidence of

Accepted Answer

A)  reciprocal mutations in the cyanelle and nuclear genomes. 
B)  horizontal gene transfer from bacterium to eukaryotes. 
C)  genetic recombination involving a protist and an archaean. 
D)  the origin of photosynthesis in protists. 
E)  transduction by a phage that infects both prokaryotes and eukaryotes. 
A)  reciprocal mutations in the cyanelle and nuclear genomes. 
B)  horizontal gene transfer from bacterium to eukaryotes. 
C)  genetic recombination involving a protist and an archaean. 
D)  the origin of photosynthesis in protists. 
E)  transduction by a phage that infects both prokaryotes and eukaryotes.

Question 10

You are designing an artificial drug-delivery "cell" that can penetrate animal cells. Which of these protist structures should provide the most likely avenue for research along these lines?

Accepted Answer

A)  pseudopods 
B)  apical complex 
C)  excavated feeding grooves 
D)  nucleomorphs 
E)  mitosomes 
A)  pseudopods 
B)  apical complex 
C)  excavated feeding grooves 
D)  nucleomorphs 
E)  mitosomes

Question 11

You are given five test tubes, each containing an unknown protist, and your task is to read the following description and match these five protists to the correct test tube.
In test tube 1, you observe an organism feeding. Your sketch of the organism looks very similar to Figure 28.1. When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 2 and 3. Chemical analysis of test tube 3 indicates the presence of substantial amounts of silica. Chemical analysis of test tube 2 indicates the presence of a chemical that is toxic to fish and humans. Microscopic analysis of organisms in test tubes 2, 4, and 5 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 4 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 5 reveals the presence of one large nucleus and several small nuclei in each organism.
   
Figure 28.1
-Test tube 4 contains

Accepted Answer

A)  Paramecium. 
B)  Navicula (diatom). 
C)  Pfiesteria (dinoflagellate). 
D)  Entamoeba. 
E)  Plasmodium. 
A)  Paramecium. 
B)  Navicula (diatom). 
C)  Pfiesteria (dinoflagellate). 
D)  Entamoeba. 
E)  Plasmodium.

Question 12

Which of the following represents the true significance of the finding that the cyanelles of P. chromatophora stem from a different type of cyanobacterium than gave rise to chloroplasts?

Accepted Answer

A)  This finding indicates that there is a second evolutionary lineage of photosynthetic eukaryotes. 
B)  This finding represents the first time that primary endosymbiosis has been directly observed. 
C)  This finding is the strongest evidence yet for the theory of endosymbiosis. 
D)  This finding is an example of the phenomenon known as "serial endosymbiosis." 
E)  This finding is the first evidence that eukaryotic cells do not necessarily digest prokaryotic cells that manage to gain access to their cytoplasm. 
A)  This finding indicates that there is a second evolutionary lineage of photosynthetic eukaryotes. 
B)  This finding represents the first time that primary endosymbiosis has been directly observed. 
C)  This finding is the strongest evidence yet for the theory of endosymbiosis. 
D)  This finding is an example of the phenomenon known as "serial endosymbiosis." 
E)  This finding is the first evidence that eukaryotic cells do not necessarily digest prokaryotic cells that manage to gain access to their cytoplasm.

Question 13

The next few questions refer to the following description.
Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.
-Which term most accurately describes the nutritional mode of healthy P. bursaria?

Accepted Answer

A)  photoautotroph 
B)  photoheterotroph 
C)  chemoheterotroph 
D)  chemoautotroph 
E)  mixotroph 
A)  photoautotroph 
B)  photoheterotroph 
C)  chemoheterotroph 
D)  chemoautotroph 
E)  mixotroph

Question 14

Which of the following is a characteristic of the water molds (oomycetes)?

Accepted Answer

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 
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

Question 15

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

Accepted Answer

A)  conjugation 
B)  horizontal gene transfer 
C)  binary fission 
D)  phagocytosis 
E)  meiosis 
A)  conjugation 
B)  horizontal gene transfer 
C)  binary fission 
D)  phagocytosis 
E)  meiosis

Question 16

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because

Accepted Answer

A)  the products of photosynthesis could not be metabolized without mitochondrial enzymes. 
B)  all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids. 
C)  mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA. 
D)  without mitochondrial CO₂ production, photosynthesis could not occur. 
E)  mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes. 
A)  the products of photosynthesis could not be metabolized without mitochondrial enzymes. 
B)  all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids. 
C)  mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA. 
D)  without mitochondrial CO₂ production, photosynthesis could not occur. 
E)  mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.

Question 17

You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (for example, 250 m deep), and can also crawl about and engulf small particles. With which two of the following structures would you provide your protist?
1)hydrogenosome
2)apicoplast
3)pseudopods
4)chloroplast from red alga
5)chloroplast from green alga

Accepted Answer

A)  1 and 2 
B)  2 and 3 
C)  2 and 4 
D)  3 and 4 
E)  4 and 5 
A)  1 and 2 
B)  2 and 3 
C)  2 and 4 
D)  3 and 4 
E)  4 and 5

Question 18

The mitosome of Giardia has no DNA within it. If it did contain DNA, then what predictions should we be able to make about its DNA?
1)It is linear.
2)It is circular.
3)It has many introns.
4)It has few introns.
5)It is not associated with histone proteins.
6)It is complexed with histone proteins.

Accepted Answer

A)  1, 3, and 5 
B)  1, 4, and 5 
C)  2, 3, and 6 
D)  2, 4, and 5 
E)  2, 4, and 6 
A)  1, 3, and 5 
B)  1, 4, and 5 
C)  2, 3, and 6 
D)  2, 4, and 5 
E)  2, 4, and 6

Question 19

Including the membrane of the surrounding vesicle, how many phospholipid (NOT lipopolysaccharide)bilayers should be found around each cyanelle, and which one of these bilayers should have photosystems embedded in it?

Accepted Answer

A)  two; innermost 
B)  two; outermost 
C)  three; innermost 
D)  three; middle 
E)  three; outermost 
A)  two; innermost 
B)  two; outermost 
C)  three; innermost 
D)  three; middle 
E)  three; outermost

Question 20

Which process results in genetic recombination, but is separate from the process by which the population size of Paramecium increases?

Accepted Answer

A)  budding 
B)  meiotic division 
C)  mitotic division 
D)  conjugation 
E)  binary fission 
A)  budding 
B)  meiotic division 
C)  mitotic division 
D)  conjugation 
E)  binary fission

Exam 28: Protists

According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of the white blood cells of animals (monocytes). If one were to erect a taxon that included all organisms that have cells with pseudopods, what would be true of such a taxon?

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

What must occur for asexual reproduction to be successful in P. chromatophora? 1)mitosis 2)S phase 3)meiosis 4)equal distribution of cyanelles during cytokinesis

Which of the following are actual mutualistic partnerships that involve a protist and a host organism?

Green algae differ from land plants in that many green algae

A crucial photosynthetic gene of the cyanobacterium that gave rise to the cyanelle is called psaE. This gene is present in the nuclear genome of the cercozoan, but is not in the genome of the cyanelle. This is evidence of

You are designing an artificial drug-delivery "cell" that can penetrate animal cells. Which of these protist structures should provide the most likely avenue for research along these lines?

Which of the following represents the true significance of the finding that the cyanelles of P. chromatophora stem from a different type of cyanobacterium than gave rise to chloroplasts?

Which of the following is a characteristic of the water molds (oomycetes)?

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because

The mitosome of Giardia has no DNA within it. If it did contain DNA, then what predictions should we be able to make about its DNA? 1)It is linear. 2)It is circular. 3)It has many introns. 4)It has few introns. 5)It is not associated with histone proteins. 6)It is complexed with histone proteins.

Including the membrane of the surrounding vesicle, how many phospholipid (NOT lipopolysaccharide)bilayers should be found around each cyanelle, and which one of these bilayers should have photosystems embedded in it?

Which process results in genetic recombination, but is separate from the process by which the population size of Paramecium increases?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

Filters