Microbiology 319 Chapter 4

Exam #2: Lectures 16-20

Indigenous Microbiota

Microbes normally residing in and on the body

Permanent Microbiota

Always present in the body

Mutualism

Both populations benefit

Amensalism

Population A is harmed, B is unaffected

Commensalism

Population A benefits, B is unaffected

Neutralism

Both are unaffected

Parasitism

Population A benefits, B is harmed

Microbes in the oral cavity are an example of…

Permanent microbiota

Crenarchaeota

Hyperthermophiles with sulfur metabolism

Genus Sulfolobus

Aerobic and anaerobic environments

Genus Thermoproteus

Strictly anaerobic

Euryarhaeota

Methanogens and halobacteria

Methanogens produce…

Methane

How many microbes can be found in one gram of soil?

10 billion

Why have many bacteria not been identified?

They are difficult to grow in lab conditions

Which technology helps detect bacteria that cannot be easily cultured?

Sequencing technology

Normal Microbiota

Collection of bacteria, archaea, and eukaryotic microbes usually colonizing our bodies

Which of the following is a type of normal microbiota?

Permanent and transient

Which body areas are normally microbe-free in healthy people?

Blood, brain, muscles

Which manual is used for identifying bacteria?

Bergey’s Manual of Determinative Bacteriology

Which manual is used for classifying bacteria?

Bergey’s Manual of Systematic Bacteriology

Traits used for bacterial classification include…

All of the above

Archaea differ from bacteria in that their membrane lipids are…

Ether-linked and branched

Archaea may have…

Pseudopeptidoglycan in cell walls

Which phylum of archaea includes methanogens and extreme halophiles?

Euryarchaeota

Which archaea phylum is mostly thermophiles with sulfur metabolism?

Crenarchaeota

Thaumarchaeota are important in which cycle?

Nitrogen

Nanoarchaeota

Small, symbiotic or parasitic

Alpha-proteobacteria often include…

Symbiotic or intracellular pathogens

Korarchaeota

Rare, thermophilic

Beta-proteobacteria may be…

Chemolithotrophs or human pathogens

Gamma-proteobacteria include… (facultative anaerobes)

Escherichia, salmonella, vibrio

Delta-proteobacteria are mostly…

Predatory or sulfur-reducing

Epsilon-proteobacteria are typically…

Microaerophilic, slender, motile

The human microbiota provides…

Mutualistic benefits

Which sequencing method is commonly used for bacterial identification?

16S rRNA sequencing

One gram of soil is dominated by which type of microbe?

Bacteria

A nonpathogen is a microorganism that…

Does not cause disease in a healthy host

A frank pathogen is one that…

Causes disease in healthy individuals with normal immune systems

Opportunistic Pathogen

Causes disease only when the host is weakened or in sterile body sites

Which of the following is used to classify bacteria?

All of the above

Which gammaproteobacteria genus is non-motile and pleomorphic?

Pasteurella

Pseudomonas species are…

Metabolically diverse with polar flagella

Enterobacteriales when motile have…

Peritrichous flagella

Campylobacter causes…

Gastroenteritis

Helicobacter is characterized by…

Multiple flagella

Alpha-proteobacteria often…

Are symbiotic or intracellular pathogens, some nitrogen-fixing

Beta-proteobacteria include…

Neisseria, bordetella, nitrosomonas

Gamma-proteobacteria are often…

Facultative anaerobes, many enteric or aquatic pathogens

Delta-proteobacteria include…

Myxococcus, bdellovibrio, desulfovibrio

Purple sulfur bacteria oxidize…

Hydrogen sulfide into sulfur and sulfuric acid

Green non-sulfur bacteria differ from green sulfur bacteria because they…

Use substrates other than sulfides for oxidation

Purple non-sulfur bacteria

Similar to purple sulfur bacteria, except they use hydrogen rather than hydrogen sulfide for oxidation

Chlamydia elementary bodies are…

Reproductively inactive and infectious

Spirochetes move using…

Axial filaments

Borrelia burgdoferi causes…

Lyme disease

Fusobacterium is mainly found in…

Human mouth

Bacteroides make up about what percentage of the human gut microbiome?

30%

Most bacteiroides are…

Mutualistic

Cytophaga are..

Motile aquatic bacteria that glide

Who first systematically proposed taxonomy?

Carlous Linneaus

What is the most general level of classification?

Domain

Which is the correct order from most general to most specific?

Domain → kingdom → phylum → class → order → family → genus → species

What is the basic unit of taxonomy?

Species

What does a “strain” represent?

Genetic variants within a species

Which of the following is used in BOTH manuals?

16S rRNA sequencing

Who proposed the 3 domain system?

Carol Woese

The 3 domain system is based on differences in…

16S rRNA sequences

Which domain has peptidoglycan in its cell wall?

Bacteria

Which genus causes pertussis?

Bordetella

Neisseria species are…

Diplococci

Enterobacteriaceae are typically…

Gram-negative rods

Which of the following is NOT part of enterobacteriaceae?

Streptococcus

EHEC causes…

Bloody diarrhea

ETEC causes…

Watery diarrhea

Helicobacter pylori is associated with…

Peptic ulcers

Clostridium species are…

Obligate anaerobic rods with endospores

Staphylococcus species are…

Facultative anaerobic cocci

Mycoplasma are characterized by…

Highly pleomorphic and very small

Which genus is known for producing geosmin (soil smell)?

Streptomyces

Which of the following is used in identification but NOT emphasized in classification?

Biochemical tests

Campylobcater is best described as…

Microaerophile with a polar flagellum

Helicobacter differs from campylobacter in that it…

Has multiple flagella

Which group is considered nonproteobacteria gram-negative bacteria?

Spriochetes

Firmicutes are also known as…

Low GC gram positive bacteria

Which genus is associated with tetanus, botulism, and gas gangrene?

Clostridium

Which genus grows well in low moisture environments?

Staphylococcus

Which genus has a high fatality rate (~20%) in infections?

Listeria

Which actinobacteria genus is a common skin commensal but can cause diphtheria?

Corynebacterium

Bacillus species are…

Facultative anaerobic rods with endosporesO

Staphylococcus are…

Cocci

Listeria is best described as…

Facultative anaerobic rod

Streptococcus species are…

Facultative anaerobic cocci

Beta-Hemolytic Streptococcus

Complete hemolysis

Enterococcus species are…

Facultative anaerobic cocci

Actinobacteria are generally…

Gram-positive with high GC content, ray-like bacteria

Which genus produces antibiotics that inhibit fungal growth?

Streptomyces

Mycelia refers to…

Dense branching filamentous networks

Which genus is associated with tuberculosis and leprosy?

Mycobacterium

Cutibacterium is associated with…

Acne