Question 1

You have discovered a photosynthetic protist that lives in fairly deep water (for example, 250 m deep).To which of the following groups should this organism be classified?

Accepted Answer

A)   diatoms
B)   green algae
C)   red algae
D)   cercozoan C

Question 2

Researchers have shown that "income levels in countries hard hit by malaria are 33% lower than in countries with similar income that are free of the disease." Which of the following statements is correct regarding this observation?

Accepted Answer

A)   This observation suggests that symptoms from malaria cause patients to lose pay because they miss work.
B)   This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.
C)   In order to understand the cause of this observation, scientists should eradicate malaria in ten countries but not in ten other comparable countries in order to experimentally test whether malaria caused the low income levels.
D)   The observation demonstrates that correlations provide excellent indications of causality. B

Question 3

Green algae and plants are placed in the same phylogenetic group. Which of the following statements presents evidence to support this classification?

Accepted Answer

A)   similarities in mitochondrial structure and enzyme sequences
B)   similarities in chloroplast structure and pigment composition
C)   similarities in cell wall and membrane structure
D)   DNA sequence similarities in genes for ribosome structure B

Question 4

Use the following information to answer the question.
Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two specialized structures called "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.
The closest living relative to P. chromatophora is the heterotroph P. ovalis. P. ovalis uses threadlike pseudopods to capture its prey, which it digests internally. Which of the following characteristics, if observed, would be the best reason for reclassifying P. chromatophora as a mixotroph instead of an autotroph?

Accepted Answer

A)   a pigmented central vacuole, surrounded by a nucleomorph
B)   a vacuole with food inside
C)   a secretory vesicle
D)   a contractile vacuole

Question 5

You have discovered a new species aquatic protist that is a primary producer. It cannot swim on its own. It appears to be resistant to physical damage from wave action due to the presence of a glass-like wall. Which of the following organisms would this organism be most like?

Accepted Answer

A)   diatom
B)   dinoflagellate
C)   apicomplexan
D)   red alga

Question 6

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question.

Based on these data, what type of organism is present in tube 3?

Accepted Answer

A)   Paramecium
B)   Pfiesteria (dinoflagellate) 
C)   Entamoeba
D)   Plasmodium

Question 7

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question.

Based on these data, what type of organism is present in tube 2?

Accepted Answer

A)   Paramecium
B)   Pfiesteria (dinoflagellate) 
C)   Entamoeba
D)   Triceratium (diatom)

Question 8

Use the following information to answer the question.
Giardia intestinalis is an intestinal parasite of humans and other mammals that causes intestinal ailments in most people who ingest the cysts. The cysts are dormant forms of this protist that are expelled in the feces of organisms that ingest them.
Which of the following structures to the cysts of Giardia function most like?

Accepted Answer

A)   mitochondria of ancestral diplomonads
B)   nuclei of archaeans
C)   endospores of bacteria
D)   capsids of viruses

Question 9

You have discovered that some members of an aquatic species of motile, photosynthetic protists have evolved to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

Accepted Answer

A)   loss of motility
B)   loss of chloroplasts
C)   gain of a rigid cell wall
D)   gain of meiosis

Question 10

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures?

Accepted Answer

A)   plasmids
B)   mitochondria
C)   nucleus
D)   chloroplasts

Question 11

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. Based on this information, to which of the following groups of algae would this organism be classified?

Accepted Answer

A)   red algae
B)   brown algae
C)   green algae
D)   golden algae

Question 12

An individual mixotroph loses its plastids, yet continues to survive. Which of the following statements best explains this organism's 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.

Question 13

Which of the following structures provides motility in species of paramecium?

Accepted Answer

A)   pseudopods
B)   a single flagellum
C)   many cilia
D)   contractile vacuoles

Question 14

Consider the following data:
∙ Most ancient eukaryotes are unicellular.
∙ All eukaryotes alive today have a nucleus and cytoskeleton.
∙ Most ancient eukaryotes lack a cell wall.
Which of the following conclusions about the first eukaryotes is most consistent with the data presented?

Accepted Answer

A)   They were very similar to a plant cell.
B)   They were anaerobic.
C)   They were capable of phagocytosis.
D)   They were photosynthetic.

Question 15

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of which of the following groups or organisms?

Accepted Answer

A)   foramifera
B)   water molds
C)   dinoflagellates
D)   oomycetes

Question 16

Trypanosome infections evade attacks by host immune systems through which of the following mechanisms?

Accepted Answer

A)   production of new cell-surface proteins with a different molecular structure by each new generation
B)   production of toxins that kill lymphocytes
C)   insertion of its DNA into the nuclear DNA of host cells
D)   infection of lymphocytes leading to a decline in the host's ability to fight infection

Question 17

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 two nuclei, one large and one small. To which of the following groups does this organism likely belong?

Accepted Answer

A)   foraminiferan
B)   radiolarian
C)   ciliate
D)   kinetoplastid

Question 18

Which of the following statements correctly describes one difference between green algae and land plants?

Accepted Answer

A)   green algae are often unicellular, while land plants are not
B)   land plants have plastids and green algae do not
C)   algae have alternation of generations but land plants do not
D)   land plants have cell walls containing cellulose but green algae do not

Question 19

Based on the phylogenetic tree in the figure, which of the following statements is correct?

Accepted Answer

A)   Excavata and SAR form a sister group.
B)   The most recent common ancestor of SAR is older than that of Unikonta.
C)   The most basal (first to diverge)  eukaryotic supergroup cannot be determined.
D)   Excavata is the most basal eukaryotic supergroup.

Question 20

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question.

Based on these data, what type of organism is present in tube 1?

Accepted Answer

A)   Paramecium
B)   Pfiesteria (dinoflagellate) 
C)   Entamoeba
D)   Plasmodium

Exam 28: The Origin and Evolution of Eukaryotes

You have discovered a photosynthetic protist that lives in fairly deep water (for example, 250 m deep) .To which of the following groups should this organism be classified?

Researchers have shown that "income levels in countries hard hit by malaria are 33% lower than in countries with similar income that are free of the disease." Which of the following statements is correct regarding this observation?

Green algae and plants are placed in the same phylogenetic group. Which of the following statements presents evidence to support this classification?

You have discovered a new species aquatic protist that is a primary producer. It cannot swim on its own. It appears to be resistant to physical damage from wave action due to the presence of a glass-like wall. Which of the following organisms would this organism be most like?

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question. Based on these data, what type of organism is present in tube 3?

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question. Based on these data, what type of organism is present in tube 2?

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures?

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. Based on this information, to which of the following groups of algae would this organism be classified?

An individual mixotroph loses its plastids, yet continues to survive. Which of the following statements best explains this organism's continued survival?

Which of the following structures provides motility in species of paramecium?

Consider the following data: ∙ Most ancient eukaryotes are unicellular. ∙ All eukaryotes alive today have a nucleus and cytoskeleton. ∙ Most ancient eukaryotes lack a cell wall. Which of the following conclusions about the first eukaryotes is most consistent with the data presented?

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of which of the following groups or organisms?

Trypanosome infections evade attacks by host immune systems through which of the following mechanisms?

Which of the following statements correctly describes one difference between green algae and land plants?

Based on the phylogenetic tree in the figure, which of the following statements is correct?

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. Use the information in the table to answer the question. Based on these data, what type of organism is present in tube 1?