Question 1

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question.

Which species might include cells that are Hfr cells?

Accepted Answer

A)  species A 
B)  species B 
C)  species C 
D)  species D

Question 2

Which of the following traits do archaeans and eukaryotes share?

Accepted Answer

A)  presence of a nuclear envelope 
B)  presence of peptidoglycan in the cell wall 
C)  sensitivity to streptomycin 
D)  presence of introns

Question 3

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?

Accepted Answer

A)  nucleoid, fimbriae, and plasmids 
B)  endospore, fimbriae, and plasmids 
C)  fimbriae, nucleoid, and endospore 
D)  plasmids, nucleoid, and endospore

Question 4

Use the following information to answer the question.
Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free oxygen (O₂) reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocysts are described as having "...a thickened cell wall that restricts entry of O₂ produced by neighboring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates."
Think about this description of the colonial aquatic cyanobacterium, Anabaena. Which of the following questions below is important for understanding how nitrogen (N₂) enters heterocysts, and how oxygen (O₂) is kept out of heterocysts?

Accepted Answer

A)  If carbohydrates can enter the heterocysts from neighboring cells via the "intercellular connections," how is it that O₂ doesn't also enter via this route? 
B)  If the cell walls of Anabaena photosynthetic cells are permeable to O₂ and carbon dioxide (CO₂), are they also permeable to N₂? 
C)  If the nuclei of the photosynthetic cells contain the genes that code for nitrogen fixation, how can these cells fail to perform nitrogen fixation? 
D)  If the nuclei of the heterocysts contain the genes that code for photosynthesis, how can these cells fail to perform photosynthesis?

Question 5

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?

Accepted Answer

A)  refrigeration: slows bacterial metabolism and growth 
B)  closing previously opened containers: prevents more bacteria from entering, and excludes oxygen 
C)  pickling: creates a pH at which most bacterial enzymes cannot function 
D)  canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells

Question 6

Photoautotrophs use

Accepted Answer

A)  light as an energy source and CO₂ as a carbon source. 
B)  light as an energy source and methane as a carbon source. 
C)  N₂ as an energy source and CO₂ as a carbon source. 
D)  CO₂ as both an energy source and a carbon source.

Question 7

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

Accepted Answer

A)  a bacterium found on another planet or moon 
B)  an archaean capable of surviving in the polar ice caps 
C)  an anaerobic archaean species 
D)  a bacterium that thrives in a highly acidic environment

Question 8

The pathogenic prokaryotes that cause cholera are ________.

Accepted Answer

A)  archaea that release an exotoxin 
B)  archaea that release an endotoxin 
C)  bacteria that release an exotoxin 
D)  bacteria that release an endotoxin

Question 9

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question.

How many of these species probably have a cell wall that consists partly of an outer membrane of lipopolysaccharide?

Accepted Answer

A)  only one species 
B)  two species 
C)  three species 
D)  four species

Question 10

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. Which of the following statements is likely to be an accurate description of this species?

Accepted Answer

A)  It is a bacterium. 
B)  The optimal pH of its enzymes will lie above pH 7. 
C)  It could inhabit hydrothermal springs. 
D)  It could inhabit alkaline hot springs.

Question 11

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question.

Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

Accepted Answer

A)  species A and B 
B)  species A and C 
C)  species B and E 
D)  species C and D

Question 12

The following question refers to the figure.
In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.

If the vertical axis of the figure above refers to relative fitness, then which of the following is the most valid and accurate measure of fitness?

Accepted Answer

A)  number of daughter cells produced per mother cell per generation 
B)  average swimming speed of cells through the growth medium 
C)  amount of glucose synthesized per unit time 
D)  number of generations per unit time

Question 13

Use of synthetic fertilizers often leads to the contamination of groundwater with nitrates. Nitrate pollution is also a suspected cause of anoxic "dead zones" in the ocean. Which of the following might help reduce nitrate pollution?

Accepted Answer

A)  growing improved crop plants that have nitrogen-fixing enzymes 
B)  adding nitrifying bacteria to the soil 
C)  adding denitrifying bacteria to the soil 
D)  using ammonia instead of nitrate as a fertilizer

Question 14

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

Accepted Answer

A)  Cell walls are made primarily of peptidoglycan. 
B)  The organism does not have a nucleus. 
C)  The lipids in its plasma membrane consist of glycerol bonded to straight-chain fatty acids. 
D)  It can survive at a temperature over 100°C.

Question 15

Use the following information to answer the question.
Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free oxygen (O₂) reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocysts are described as having "...a thickened cell wall that restricts entry of O₂ produced by neighboring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates."
Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what mechanism might nitrogen-fixing prokaryotes use to protect these enzymes from oxygen?

Accepted Answer

A)  couple the nitrogen fixation enzymes with photosystem II (the photosystem that splits water) 
B)  package the nitrogen fixation enzymes in membranes that are impermeable to all gases 
C)  live only in anaerobic environments 
D)  package the nitrogen fixation enzymes in membranes that are impermeable to nitrogen gas (N₂).

Question 16

Use the information in the following paragraph to answer the question.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of ________.

Accepted Answer

A)  gram-negative cell wall 
B)  peptidoglycan in the cell wall 
C)  lipopolysaccharides in the cytoplasm 
D)  long polypeptides in the cell wall

Question 17

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

Accepted Answer

A)  extreme halophiles 
B)  extreme thermophiles 
C)  methanogens 
D)  cyanobacteria

Question 18

Use the information in the following paragraph to answer the question.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
Which of the following statements about the cell wall is most probable?

Accepted Answer

A)  Its innermost layer is composed of a phospholipid bilayer. 
B)  After it has been subjected to Gram staining, the cell should remain purple. 
C)  It has an outer membrane of lipopolysaccharide. 
D)  It is mostly composed of a complex, cross-linked polysaccharide.

Question 19

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question.

Species D is pathogenic if it gains access to the human intestine. Which other species, if it coinhabited a human intestine along with species D, is most likely to become a recombinant species that is both pathogenic and resistant to some antibiotics?

Accepted Answer

A)  species A 
B)  species B 
C)  species C 
D)  species E

Question 20

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?

Accepted Answer

A)  It is able to form colonies and produce oxygen. 
B)  It is an endosymbiont. 
C)  It forms chains called mycelia. 
D)  It lacks cell walls.

Exam 27: Bacteria and Archaea

The following table depicts characteristics of five prokaryotic species (A-E) . Use the information in the table to answer the question. Which species might include cells that are Hfr cells?

Which of the following traits do archaeans and eukaryotes share?

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?

Photoautotrophs use

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

The pathogenic prokaryotes that cause cholera are ________.

The following table depicts characteristics of five prokaryotic species (A-E) . Use the information in the table to answer the following question. How many of these species probably have a cell wall that consists partly of an outer membrane of lipopolysaccharide?

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. Which of the following statements is likely to be an accurate description of this species?

The following table depicts characteristics of five prokaryotic species (A-E) . Use the information in the table to answer the question. Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

Use of synthetic fertilizers often leads to the contamination of groundwater with nitrates. Nitrate pollution is also a suspected cause of anoxic "dead zones" in the ocean. Which of the following might help reduce nitrate pollution?

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?