Deck 21: Protists, Prokaryotes and Viruses

Question 1

Jennifer was camping and decided to drink water from a clear mountain stream. Her fellow campers suggested she filter the water but she ignored their advice and drank directly from the stream. A few days later she experienced intense abdominal pain and severe diarrhea. What is the most probable agent of her misfortune?

A) Paramecium caudatum
B) Giardia intestinalis
C) Plasmodium falciparum
D) Neisseria gonorrhoeae
E) Yersinia pestis

Answer 1

Giardia intestinalis

Question 2

Unlike virtually all other eukaryotes, diplomonads lack mitochondria. Why aren't these organisms considered to represent a state most like the common ancestor to all other eukaroyotes?

A) They have endosymbiotic relationships with other bacteria.
B) They do not use ATP to power their cells.
C) They have non-functional mitochondrial remnants.
D) They are phototrophic.

Answer 2

They have non-functional mitochondrial remnants.

Question 3

Which of the following statements would not be consistent with the theory for the endosymbiotic origin of mitochondria and chloroplasts?

A) Mitochondria and chloroplasts have their own DNA enclosed within a nuclear envelope.
B) The composition of the outer membrane of chloroplasts and mitochondria is similar to the plasma membrane of eukaryotic cells.
C) The composition of the inner membrane of chloroplasts and mitochondria is similar to the plasma membrane of prokaryotic cells.
D) Mitochondria and chloroplasts have some enzymes unique to them.
E) Genes encoded within mitochondria and chloroplast indicate a closer relationship to prokaryotes than do most nuclear genes.

Answer 3

Mitochondria and chloroplasts have their own DNA enclosed within a nuclear envelope.

Question 4

Which feature would exclude a newly discovered organism from being categorized as a protist?

A) Lacking functional mitochondria
B) The absence of a nuclear envelope
C) Having cellulose cell walls
D) Using pseudupodia for locomotion

Question 5

The grouping Protista is

A) a valid evolutionary grouping that includes organisms that are more closely related to each other than to other organisms
B) A convenient grouping of eukaryotic organisms that have some similarity but are hard to classify
C) A group of exclusively microscopic organisms

Question 6

Which feature would be the least useful in determining if a protist were a close relative of plants?

A) Cellulose cell walls
B) Capacity for photosynthesis
C) Plasmodesmata between cells
D) Enzymes for ATP production

Question 7

An easy way to describe a radiolarian would be to say that it is

A) Ameoba in a diatom shell
B) A diatom with many flagella
C) A red algae trapped in a glass casing
D) A paramecium that is capable of photosynthesis

Question 8

Cercozoans are a widely diverse group of amoeboid flagellated protists that have been grouped together based on genetic similarities.

Question 9

Once a prophage is formed, the viral genes are reproduced every time the bacterium multiplies. The genes that encode the lytic cycle are held in check by a repressor protein. Stress induces the formation of proteases that degrade the repressor. How would this affect the prophage?

A) Apoptosis would be induced.
B) The bacterium rejects the viral genes.
C) The virus enters the lytic cycle.
D) The bacterial genome is denatured.

Question 10

Why do viruses only infect specific types of cells?

A) Viruses infect the first cells they encounter.
B) If a host cell is weakened, viruses have an easier time infecting it.
C) The host cells have the correct surface receptor that the virus can fit into.
D) Viruses only attack epithelial cells, such as the cells lining the lungs.
E) The initial choice is random but once a cell type is chosen it becomes the preferred host.

Question 11

Flu shots are vaccines against the most common strains of the flu virus. Most vaccines are rarely changed but new flu vaccines are produced every year. Why are flu shots constantly being reformulated?

A) The flu virus is not completely known.
B) Certain parts of the viral genome are reshuffled by mutations and recombination.
C) The virus mixes with prions.
D) The virus shifts from RNA to DNA.

Question 12

Which of the following statements about the types and subtypes of the influenza (flu) virus is false?

A) Of the three major types of flu virus (A, B, and C), only Type A can occur in humans, other mammals, and birds.
B) Flu subtype is determined by the kinds of proteins representing the H and N protein spikes making up the capsid of the virus.
C) The A(H2N2) and the A(H3N2) strains of the virus require different vaccines.
D) High mutation rates create more diversity in strains of flu than does genetic recombination.
E) Genetic recombination between flu strains from different species is common.

Question 13

The fungus Penicillium produces a compound that blocks peptidoglycan assembly. How does this kill bacteria?

A) It stops the functioning of their ribosomes
B) It prevents the assembly of the cell wall
C) It disrupts DNA uncoiling
D) It blocks folate synthesis

Question 14

Which method of horizontal gene transfer is most likely to transfer 2 genes that are near each other on a bacterial chromosome?

A) F+ conjugation
B) Transformation
C) Lytic viral infection
D) Transduction

Question 15

DNA replication and gene expression in archaeans more closely resemble eukaryotic cells than the same processes in bacteria. However both Bacteria and Archaea are prokaryotic. What does this suggest?

A) Eukaryotic cells are descended from modern Archaeans.
B) Bacterial cells are not related to Archaeans.
C) Eukaryotic cells shared a more recent common ancestor with Archaeans than with bacterial cells.
D) There must have been 2 origin events, one producing the bacteria and the other producing Archaeans and eukaryotic cells.