Introduction to Microbiology in Agriculture Flashcards
Intro
Roles of Micro-organisms
They cycle soil nutrients, aid in digestion, and play roles in food processing.
How were Eukaryotic cells formed
Formed from symbiotic associations among archaea, proteobacteria (mitochondria), and cyanobacteria (chloroplasts).
Examples of Microbial roles in normal health and function
Rhizobia bacteria fix nitrogen for legumes, aiding plant growth.
Ruminants rely on gut microbes to digest cellulose in their diet.
What effects can Micro-organisms have on food
Food spoilage
molds such as in blue cheese
What are the four types of micro-organisms
photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs.
What type of Microorganism are pathogenic bacteria
Chemoheterotrophs
Main differences between Eukaryotes and prokaryotes
prokaryotes are smaller, can be anaerobic, and lack membrane-bound organelles
Differences between bacteria and viruses
Structures: Viruses are particles (virions); bacteria are single cells.
Genomes: Viruses contain DNA or RNA; bacteria have DNA.
Replication: Viruses replicate within living cells; bacteria mostly by binary fission.
What is involved in the diagnosis of a bacterial disease
detecting the organism, its products, or immune responses.
What are 3 methods of diagnosing bacterial disease
Microscopy, culture, and molecular methods like PCR are common.
What are bacteria?
Bacteria are microscopic, single-cell, self-replicating organisms that exist in a wide variety of shapes and sizes
Why is it important to classify and name bacteria?
To group similar organisms together and ensure consistent identification and discussion of specific bacteria.
How were bacteria historically classified?
According to their phenotype, including observable traits such as size, shape, arrangement, and structures like endospores, capsules, and flagella.
What modern method is used to classify bacteria?
By their genotype or genetic makeup, particularly through sequencing 16S rRNA genes and whole genome sequencing.
What are 16S rRNA genes used for in bacterial classification?
To track evolutionary changes and construct phylogenetic trees due to their essential role in mRNA translation and high conservation.
What is the binomial naming system for bacteria?
A system where the first name is the genus (capitalized) and the second name is the species (lowercase), both italicized in print or underlined when handwritten.
What is an example of bacterial nomenclature and its abbreviation?
Escherichia coli, often abbreviated as E. coli.
What defines a bacterial species?
A group of organisms that are very similar genetically and phenotypically.
What major reclassification occurred in 2016 due to 16SrRNA gene analysis?
Clostridium difficile was reclassified to Clostridioides.
What is the ‘International Code of Nomenclature of Prokaryotes’?
A set of rules for naming bacterial species, published by the ‘International Journal of Systematic and Evolutionary Microbiology’.
How can bacterial phenotypes be observed?
Through their growth in the presence of oxygen, on selective or differential media, and by staining and microscopy.
What is the Gram reaction?
A staining method that differentiates bacteria by their cell wall composition, staining them either purple (gram-positive) or pink/red (gram-negative).
What structures can be observed using special stains in bacteria?
Endospores, capsules, and flagella.
How is motility observed in bacteria?
Microscopically using a hanging drop preparation and macroscopically by using semisolid motility media.
What biochemical tests can identify bacterial metabolic traits?
Tests for enzymes such as catalase, oxidase, coagulase, and urease.
What are taxonomic keys used for in bacteriology?
To identify bacteria at the genus or species level based on their positive or negative results to various traits and tests.
How is DNA used for bacterial identification and classification?
Through techniques like PCR and genomic sequencing, including 16SrRNA gene sequencing and multi-locus sequence typing (MLST).
Why is it important to identify different bacterial strains?
Because different strains within the same species can have varying abilities to cause disease.
Give an example of a bacterial species with different strains having different pathogenic abilities.
Escherichia coli, which includes a harmless commensal strain, a probiotic strain, and pathogenic strains causing diseases.
Why is it important to identify bacterial species and strains correctly?
To ensure the correct bacteria are used for specific applications and to apply the appropriate treatment to reduce disease burden.
