Question 1

Microbiologists use the Gram stain to aid in the identification of bacteria.What is the major difference between Gram-positive and Gram-negative bacteria?

Accepted Answer

A)  structure of the lipids in the plasma membrane
B)  presence or absence of muramic acid in the cell wall
C)  presence or absence of peptidoglycan in the cell wall
D)  presence or absence of outer plasma membrane D

Question 2

You acquire a soil sample and run an enrichment culture on it.You provide the organisms in the culture with all of the ingredients required for growth except for nitrogen.What result do you expect to have at the end of your experiment?

Accepted Answer

A)  Nitrogen-fixing bacteria will significantly outnumber those incapable of fixing nitrogen.
B)  Nitrogen-fixing bacteria will not be present in the culture.
C)  Nitrogen-fixing bacteria will be present but not at significantly greater numbers than non-nitrogen-fixing species.
D)  Nitrogen-fixing bacteria will be present,but will be significantly outnumbered by non-nitrogen-fixing species. A

Question 3

When some bacteria use lactose as a source of energy,they produce propionic acid and CO₂.What is the name for this process?

Accepted Answer

A)  fermentation
B)  cellular respiration
C)  chemical synthesis
D)  photosynthesis
E)  carbon fixation A

Question 4

While examining soil from a cornfield,you found a new type of bacteria that turns purple when treated with Gram stain.What lineage might it belong to?

Accepted Answer

A)  Spirochaeles
B)  Proteobacteria
C)  Cyanobacteria
D)  Firmicutes
E)  Chlamydiales

Question 5

An organic solvent widely used in industrial processes 1,1,1-trichloroethane (TCA) is a major environmental pollutant affecting human health and damaging the ozone layer.Recently researchers isolated the first bacteria able to degrade TCA.They found that the bacteria use hydrogen as an electron donor,TCA as electron acceptor,and acetate as a carbon source.Based on the preceding information,deduce the method used to isolate these bacteria.

Accepted Answer

A)  Gram staining
B)  enrichment culture
C)  direct sequencing
D)  seeding

Question 6

Which of the following describe all existing bacteria?

Accepted Answer

A)  pathogenic,omnipresent,morphologically diverse
B)  extremophiles,tiny,abundant
C)  small,harmful,fast-growing
D)  tiny,ubiquitous,metabolically diverse
E)  morphologically diverse,metabolically diverse,extremophiles

Question 7

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)  You determine that it can cause Lyme disease.
E)  It lacks cell walls.

Question 8

What do Bacteria have in common with Archaea but not with Eukarya?

Accepted Answer

A)  unicellular structure
B)  peptidoglycan cell walls
C)  transcription mechanism begins with formylmethionine
D)  absence of nucleus
E)  DNA associated with histone proteins

Question 9

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 10

Some researchers have begun attempting to clean up oil spills by adding nonindigenous microbial hydrocarbon degraders to the spill,in the hopes that these bacteria will neutralize the dangerous chemicals in the spill.This is an example of _____.

Accepted Answer

A)  bioremediation via fertilization
B)  seeding
C)  production of a new antibiotic
D)  use of extremophiles for cleanup of organic solvents

Question 11

Researchers have found a new type of bacteria,and they want to determine its phylum.What would be the most reliable method to do so?

Accepted Answer

A)  Conduct a Gram-stain test.
B)  Perform an analysis of metabolic pathways.
C)  Determine the ribosomal RNA sequence of the bacteria.
D)  Analyze the morphological characteristics of the bacteria.

Question 12

During cellular respiration,some bacteria use CH₄ as an electron donor and O₂ as an electron acceptor.What is the name for this group of bacteria?

Accepted Answer

A)  methanogens
B)  methanotrophs
C)  organotrophs
D)  nitrifiers

Question 13

A biologist trying to determine the mechanism of ATP production in a newly discovered bacterium provides several different substrates on which the bacteria can feed.Which of the following results would indicate that the species uses fermentation to produce ATP?

Accepted Answer

A)  The bacteria utilize glucose,and produce CO₂ as a by-product of respiration.
B)  After the bacteria break down their substrate,the biologist notices a rotten egg smell.
C)  The biologist discovers that the bacteria are able to produce organic molecules by metabolizing methane.
D)  After exposure to amino acids,the bacteria produce a smell like rotting flesh.

Question 14

What is the characteristic feature of the Chlamydiales phylum?

Accepted Answer

A)  unusual flagella
B)  formation of colonies
C)  rod shape
D)  parasitic life cycle

Question 15

What organisms are most numerous on Earth?

Accepted Answer

A)  eukaryotes
B)  archaea
C)  prokaryotes
D)  plants
E)  insects

Question 16

Multicellularity and large body size of eukaryotic organisms requires high metabolic rates and efficient ATP production by aerobic respiration.How did bacteria change Earth's atmosphere to enable aerobic respiration?

Accepted Answer

A)  Oxygenic photosynthesis by cyanobacteria significantly increased the amount of oxygen in the atmosphere.
B)  Splitting of water during anaerobic respiration by cyanobacteria dramatically increased the amount of oxygen in the atmosphere.
C)  Nitrogen fixation by cyanobacteria decreased the amount of nitrogen in the atmosphere,leading to simultaneous increase of oxygen.
D)  Anaerobic respiration by cyanobacteria increased the amount of oxygen in the atmosphere by reducing the amount of iron oxides that are able to react instantly with oxygen.

Question 17

A newly discovered organism is found to use sulfide (S²−)for aerobic respiration and use CO₂ from the air as a source of carbon,much like a plant.This organism must be a(n)_____.

Accepted Answer

A)  photoautotroph
B)  chemoorganoautotroph
C)  photoheterotroph
D)  chemolithotrophic heterotroph
E)  chemolithoautotroph

Question 18

Which of the following groups is characterized by unusual flagella contained within a structure called the outer sheath?

Accepted Answer

A)  Spirochaeles
B)  Proteobacteria
C)  Firmicutes
D)  Chlamydiales
E)  Euryarchaeota

Question 19

What is the right progression of steps for a direct-sequencing experiment?

Accepted Answer

A)  Lyse cells,purify DNA,amplify genes by PCR,and insert genes into plasmid.
B)  Lyse cells,insert genes into plasmid,purify DNA,and amplify genes by PCR.
C)  Lyse cells,insert genes into plasmid,amplify genes by PCR,and purify DNA.
D)  Purify DNA,amplify genes by PCR,lyse cells,and insert genes into plasmid.

Question 20

What is the major goal of cellular respiration?

Accepted Answer

A)  reduce an electron acceptor molecule
B)  supply cell with fixed carbon
C)  produce ATP
D)  generate O₂
E)  utilize glucose

Exam 28: Bacteria and Archaea