Question 1

Except that they are not produced in the cytoplasm,conidia produced by Streptomyces spp.are chemically quite similar in composition to endospores produced by Bacillus spp.

Accepted Answer

While both conidia and endospores are resistant, dormant forms of bacterial cells, they differ in their mode of production and chemical composition. Conidia are produced through a process called sporulation, which occurs in specialized structures called spore-bearing hyphae. They are typically composed of a single cell and lack some of the protective structures found in endospores, such as a thick coat of keratin-like proteins. In contrast, endospores are produced by a process called sporogenesis, which occurs within the cytoplasm of the bacterial cell. They are highly resistant to environmental stressors and contain a variety of protective structures, including a spore coat, cortex, and inner membrane.

Question 2

Considering the evolution of Bacteria,the criteria used for taxonomy,and the genetic requirements for individual metabolic pathways,explain how it is unlikely to observe three genera of the same family where one genus has strict anaerobes that degrade only small aromatics,another genus degrades large molecular weight sugars aerobically,and a third is a photoautotroph.

Accepted Answer

The answer of Considering the evolution of Bacteria,the criteria used...

Question 3

Chlamydiae are MOST commonly transmitted throughout environments by insects.

Accepted Answer

Chlamydiae are most commonly transmitted through sexual contact, but can also be spread from mother to child during birth or through contaminated surfaces such as doorknobs or toilet seats. Insects are not a common mode of transmission.

Question 4

Explain how the enteric bacteria can be differentiated by the type and proportion of fermentation products produced by the anaerobic fermentation of glucose.

Accepted Answer

The answer of Explain how the enteric bacteria can be...

Question 5

Cytophaga columnaris causes columnaris (or "cottonmouth")disease in fish such as salmon.Based on the taxonomic group this species is a part of,predict some of the activities this bacterium has during infection of fish.Also mention a related taxon that likely has some of the same functions and another taxon that does not.

Accepted Answer

The answer of Cytophaga columnaris causes columnaris (or "cottonmouth")disease in...

Question 6

Deinococcus radiodurans is capable of withstanding especially high levels of radiation,and the carotenoids they produce enhance this resistance.

Accepted Answer

Deinococcus radiodurans is known to be highly resistant to radiation, and studies have shown that its production of carotenoids helps to enhance this resistance by protecting DNA from damage caused by ionizing radiation.

Question 7

Simple staining and microscopy could easily distinguish the different taxa intermixed within a community of Sarcina,Staphylococcus,and coryneform bacteria.

Accepted Answer

Simple staining and microscopy can differentiate different bacteria based on their cell morphology and arrangement. Sarcina bacteria have a characteristic cuboidal shape, while Staphylococcus bacteria form clusters, and coryneform bacteria have a rod-like shape. Thus, they can be easily distinguished in a mixed community using simple staining and microscopy.

Question 8

When looking under a transmission electron microscope,you observe anammoxosomes in one bacterium and pirellulosome in another bacterium.BOTH taxa are likely a part of Planctomycetes.

Accepted Answer

Anammoxosomes and pirellulosomes are both specialized membrane-bound cell compartments found in different members of Planctomycetes, a phylum of bacteria known for their unique features such as lack of peptidoglycan cell walls and compartmentalization. Therefore, it is likely that the two bacteria observed are both part of the Planctomycetes phylum.

Question 9

Select a group within Bacteria that has a rare structural morphology observable with a microscope.Describe the appearance,the group that it corresponds to,and another group that would certainly be ruled out when observing such a morphology.

Accepted Answer

The answer of Select a group within Bacteria that has...

Question 10

Some Streptomyces spp.can biosynthesize several chemically unrelated structures that act as different antibiotics.

Accepted Answer

Streptomyces spp. are known for their ability to produce multiple chemically diverse secondary metabolites, many of which are antibiotics. Some strains can even produce multiple types of antibiotics simultaneously.

Question 11

Some species in the genus Acidobacteria are classified in Bacteria while others are considered Archaea.

Accepted Answer

All species in the genus Acidobacteria are classified as Bacteria, none are considered Archaea.

Question 12

Due to the slow and varied growth rates,mycobacteria are commonly grouped into either slow growing or very slow growing,which has consequences on the growth medium selected for culturing.

Accepted Answer

The answer of Due to the slow and varied growth...

Question 13

Thermotoga are hyperthermophiles and appear relatively closely related to Archaea in comparison to other bacteria such as Salmonella.

Accepted Answer

Thermotoga are a group of bacteria that are adapted to live in extremely high temperatures, and share genetic and metabolic characteristics with Archaea that also thrive in extreme environments. Compared to other bacteria such as Salmonella, Thermotoga are more closely related to Archaea based on genetic analysis.

Question 14

Describe the stages chlamydia cells go through during infection of human cells and the significance for the key steps in the cycle.

Accepted Answer

The answer of Describe the stages chlamydia cells go through...

Question 15

The hypothesis that H₂ was a key electron donor for energy metabolism in primitive organisms is supported by it being such a common trophic strategy in Aquificae.

Accepted Answer

Aquificae are a group of thermophilic bacteria that are known for their ability to generate energy from hydrogen gas (H₂) oxidation. This suggests that H₂ was a key electron donor for energy metabolism in the early stages of life on Earth.

Question 16

During stationary phase,group members of Serratia produce prodigiosins that contain pyrrole.Considering its structural relatedness to other pyrrole-containing molecules of known function (e.g.,chlorophylls,bacteriochlorophylls,porphyrins),propose a potential ecological role for these compounds in soil where they are involved in something other than photosynthesis.

Accepted Answer

The answer of During stationary phase,group members of Serratia produce...

Question 17

Which group of bacteria is most famous for their diversity of antibiotics produced? Hypothesize an ecological role production of these antibiotics might have in such environments where they are not produced at high enough levels to kill bacteria.

Accepted Answer

The answer of Which group of bacteria is most famous...

Question 18

Antibiotics that disrupt or halt cell wall biosynthesis are actually ineffective at harming growth of mycoplasmas.

Accepted Answer

Mycoplasmas lack a cell wall, so antibiotics that target cell wall synthesis, such as penicillin, are ineffective against them.

Question 19

Even to a well-trained microbiologist,isolates of Streptomyces when grown on a nutrient agar plate can appear as though they are fungi.Describe key similarities of how these two unrelated groups can so easily be mistaken for each other,and then propose methods to conclusively distinguish between them.

Accepted Answer

The answer of Even to a well-trained microbiologist,isolates of Streptomyces...

Question 20

Proteobacteria members thrive in soils and occur at high concentrations as well.Other bacterial taxa are considered much less diverse in terms of their metabolic capabilities.Due to the role isolation has in discovering metabolic pathways,consider how obtaining hundreds of new isolates from a less studied phylum might change our views on metabolic diversity.Predict how the results of discovering another highly metabolically diverse group might be handled in terms of taxonomic assignment.

Accepted Answer

The answer of Proteobacteria members thrive in soils and occur...

Quiz 15: Diversity of Bacteria